Flowmaster v7.0 Easy Guide

Easy Guide

Where to Set Elevation

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Easy Guide - Where to Set Elevation

Introduction Flowmaster can take account of elevation by inputting ‘level’ data at nodes. The level is from a fixed datum point as shown below.

Example Create a new network as below by using pipes, bends and pumps, using the values shown on the diagram. Whilst inputting the data, select the analysis type to be Incompressible Steady State to show the data fields which have to be completed. Note the negative figure on the flow source to highlight it is a demand.

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Easy Guide - Where to Set Elevation Once modelled, run the model as steady state. Look at the results for the node nearest the flow demand. This should show a pressure at node level result of 2.27 bar. Clear the current collection, and then collect the two nodes between the bend and the flow demand components. Click on the level property in the data fields, and then select the toggle icon (see right) and set the level of both nodes to 10m. Re-run the simulation. The pressure at node level should now be 1.29 bar. You can see from the results that Flowmaster also produces a result which is termed node pressure. The difference between these two results being of course that node pressure is the result from a network which is assumed level i.e. no elevation. This is defined as:

Pressure Absolute Total Pressure =

P

Whereas Ptotal =

P

And Absolute Static Pressure =

P

total + ATM Pressure

static + static + ATM Pressure

[note. Pstatic is the gauge static pressure]

Pressure at Node level Pat_node_level =

P

Or Pat_node_level =

P

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static + Pdynamic total -

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Defining a Pressure Loss Component

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Easy Guide - Defining a Pressure Loss Component

Introduction Flowmaster has a discrete loss component which allows engineers to model networks without a high level of detail. This may be used to represent a series of pipes where it is not necessary to understand the behaviours within the series, or where there are many branches of a pipe system and the user is only concerned with what happens at one particular branch.

Application Example Consider the example below as modelled in Flowmaster.

In this case, the engineer is trying to calculate the flow rate necessary to conform to the two known pressure levels. Knowing the pipe diameter (and bend) remains constant at 1.6m, and it is not necessary to understand other detail, this network can be defined as shown over.

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Easy Guide - Defining a Pressure Loss Component

The discrete loss component is defined by cross sectional area and a Forward and Reverse Loss Coefficient. Cross sectional area in this case is defined by πr2 where r=0.8m. The Forward Loss Coefficient (k) is calculated by

k=

2 x Pressure drop (Pa) Liquid Density (kg/m3) x Velocity (m/s) 2

and in the example opposite is

k= k=

2 x (200,000-150,000) 998 x 19.12 0.27

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Pumps and Pump Controllers

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Easy Guide - Pumps and Pump Controllers

Application Example Consider the network below

Liquid is being pumped from a reservoir through a pump and valve into a pipe. The pressure condition is set at atmospheric (or 1 bar in this example). We would like to design the network and then control the pump speed in order to understand the flow rate at the end of the pipe as the pump changes speed.

Analysis Type In order for Flowmaster to analyse this example, you must first change the analysis type. Flowmaster makes it simple by only showing the data fields required for the selected analysis. For this example we are looking for pump performance over time – therefore a transient study. As this example is looking at water, we need to input data for an incompressible transient study. Choose the correct study type from the drop down box halfway down the data tab (see above right).

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Easy Guide - Pumps and Pump Controllers

Pumps Next let’s look at what data is required for the pump to be defined.



As with all Flowmaster components the pink fields are mandatory. Hopefully you will have a full set of manufacturer’s data in order to define the pump when you come to run your own analysis. However, some of the fields can be calculated.

Pump and Motor Inertia can be calculated from the following equations, ref Thorley (Fluid Transients in Pipeline Systems, 1991, ISBN 0-9517830-0-9): Pump Inertia =

Motor Inertia =

Where W = Pump Power (kW), N = Pump Speed (r.p.m x 10-3), I = Inertia (kg/m2) Pump Power (W) = where ρ = fluid density, η = overall efficiency, g = gravity, H = Duty Head Q = Duty flow rate Frictional Torque

=

Note: This can be used in the absence of manufacture data. Speed Ratio = Rated Flow, Head and Speed are based on Best Efficiency point from manufacture’s data.

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Easy Guide - Pumps and Pump Controllers

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Easy Guide - Pumps and Pump Controllers

Model the network above, using the numbers shown. In order to control the pump speed you need to turn the initial logic state of the of the radial pump to setting 1 – Motor On – Controlled Torque/ Speed. You will also need to add the pump speed controller to define how the pump speed changes. Add in a gauge to the end of the pipe so you can measure the mass flow rate. Once the model is complete, select the simulation tab, and set the time step and the start and end times as shown in red on the right. Then click run. Once completed, select the results tab and double click the result file you have just created. Double click on the pump, and ensuring the results radio button is highlighted, plot the rotational speed of the pump by selecting the graph icon in the inspect window, as shown in red in the image on the right. The plot will appear on a separate tab to your network – named ‘plot 1’. In the upper left hand corner of the graph there are some graph customise icons. Pick on the ‘overlay’ option, and go back to your network by choosing the correct tab.

Now double click on the gauge, and again select the graph icon in the inspect window.

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Click back on the plot 1 tab and you should be able to see a plot similar to the one shown below.

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Easy Guide

Pressure Loss Validation

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Easy Guide - Pressure Loss Validation Validation of pressure loss using a basic Flowmaster model and Hand Calculations. P1 is the pressure into the system (= 437000 Pa) Q is the volumetric flow rate (=65 l/min or 0.0010833 m3/s), set as -0.0010833 m3/s D is the pipe diameter (= 0.015m2) L is the pipe length (= 0.6m) k is the Absolute Roughness (= 0.000025m), used to calculate friction loss

Flowmaster Model A simple network in Flowmaster as shown below:

This gives a value of P2 = 418558 Pa (result at node 2 – Downstream Node)

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Easy Guide - Pressure Loss Validation The results for the pipe are shown below:

These results can be compared to those obtained from hand calculations. These hand calculations are shown below:

Velocity Q = Av Where Q = 0.0010833 m3/s A = π D24 (D = 0.015 m) This gives v = 6.14 m/s Flowmaster gives v = 6.13 m/s This corresponds to a 0.13% difference.

Reynolds Number Re = ρvDμ Where ρ = 1000 kg/m3 v = 6.14 m/s μ = 0.001002 This gives Re = 91916.2 Flowmaster gives Re = 91605.6 This corresponds to a 0.3% difference.

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Easy Guide - Pressure Loss Validation

Loss Coefficient The loss coefficient can be worked out by first evaluating the friction factor. The relevant equations are shown below:

Where k is the Absolute Roughness (= 0.000025m) D is the diameter (=0.015m) Re is the Reynolds number (=91605.6) This gives a value of f = 0.0246 This value of f can now be used to work out K, the loss coefficient as shown over:

This gives K = 0.983 (0% discrepancy with Flowmaster value)

Pressure Drop These values can now be substituted into the following equation to work out the pressure difference:

This can be simplified to:

P2− P1=K ρ v22

This gives a pressure difference of 0.185 bar. Flowmaster gives a value of 0.184 bar. This corresponds to a 0.5% difference.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Net Positive Suction Head

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Easy Guide - Net Positive Suction Head The existing rotodynamic pumps do not currently consider NPSH. However this is recognised as a limitation and development is planned to address this in a future version. In the interim a methodology has been devised, using existing capability, to identify when NPSH available (NPSHA) is less than NPSH required (NPSHR). This methodology does not modify the pump performance. The schematic below shows a pump in a test system consisting of a tank and suction line and discharge flow demand. The yellow, round components are gauges to measure; suction pressure, fluid temperature, and delivery flow rate

Flowmaster NPSH Model

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Easy Guide - Net Positive Suction Head

Setting up the Model In the Data Tab, select the Incompressible Transient filter as shown below

 

Reservoir: Constant Head



Pipe: Cylindrical Rigid



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Easy Guide - Net Positive Suction Head Pump: Radial Flow



Suter Curves left as default Flowmaster curves Gauge Template Pressure Gauge



Gauge Template Flow Rate Gauge

Gauge Template Temperature Gauge

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Easy Guide - Net Positive Suction Head Gauge 4 (Flow rate) is connected to input signal 3 on the Controller component and Arm 2 of the Pump component. Gauge 3 (Pressure) is connected to input signal 1 on the Controller component and Node 1 (just upstream of the pump) Gauge 7 (Temperature) is connected to input signal 2 on the Controller component and Node 1 (just upstream of the pump) The NPSH Monitor component is a Controller Template. The yellow, square component calculates NPSH Available (NPSHA) and compares this to a NPSH Required (NPSHR) value defined as a curve of NPSHR Vs Flow Rate. Controller Template

Script/Equation Identifier: NPSH_Vdotnet, this script is written in VB.Net

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Easy Guide - Net Positive Suction Head

Data Curve 1 is the Vapour Pressure v Temperature Curve for Glycol/Water (50/50) and is available in the Performance Data > Materials> Incompressible library

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Easy Guide - Net Positive Suction Head Data Curve 2 is the Density v Temperature – Water, and is available in the Performance Data > Materials> Incompressible library

Data Curve 3 is the NPSHR Vs Flow Rate curve and is defined below

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Easy Guide - Net Positive Suction Head To define a curve, Right click on a folder within Performance Data, i.e. User defined and select New > Curve and enter the data as shown right.

Run the Incompressible Transient with the Simulation Data inputs shown right.

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Easy Guide - Net Positive Suction Head

Results If the NPSHA is less then NPSHR then the controller outputs a result of 1 to record that the pump could cavitate. If NPSHA is greater than NPSHR then the controller outputs a result of 0 to record that the pump is not cavitating. The following graph shows a sample set of results for pump flow increasing (Blue Line), suction pressure dropping (Red Line), and pump cavitation occurring at about 1.7secs (Green Line).

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Convergence and Tolerance

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Easy Guide - Convergence and Tolerance Flowmaster Convergence and Tolerance Criteria allow the adjustment of the Flowmaster solver control parameters.

Flowmaster Solver Control Parameters The solver control parameters are set on the Flowmaster Simulation Data tab, under Convergence & Tolerance Criteria. These settings affect the rate at which Flowmaster converges to a solution.

In general, we recommend that the default values are used as they are considered well suited for general Flowmaster analyses. Our general advice if you do experience convergence problems, check and recheck the input data. If, after making these checks, you believe that solver control parameters require adjustment, then the following information will be of use.

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Easy Guide - Convergence and Tolerance

Flowmaster Tolerances Flowmaster checks total pressure and temperature tolerances at every node. Mass flow rate tolerances are checked at every branch and mass flow continuity is checked at every node to a tolerance of 1/10th of the branch mass flow tolerance. These sequences of checks are shown diagrammatically in the figure at the end of this paper. The default percentage pressure tolerance is set at 0.05% and has proven satisfactory for a wide range of applications when used in conjunction with the standard weighting factor (see below). In some situations (high absolute pressure values and small pressure differentials) a tighter tolerance may be appropriate. But in compressible flows, with coupling of pressure with the mass flow solution through the density term, these tighter tolerances may be too severe. ·The absolute pressure tolerance should be well below the minimum pressure of interest. The default of 1 Nm-2 (1 Pa) is usually appropriate. Its main purpose is to prevent the percentage tolerance test from becoming too severe when pressures are very close to zero. The default percentage mass flow rate tolerance is set to 0.05% and has proven satisfactory for a wide range of applications, when used in conjunction with the standard weighting factor. The absolute mass flow tolerance should be well below the minimum mass flow rate of interest. It is intended to prevent the percentage test from being too severe when flows are very close to zero e.g. in a branch with a closed end or shut valve. The default value of 0.5gms-1 can be too high if low flow rates are being used (e.g. grams per second). The default weighting factor (or relaxation) is set to 0.5 and should be used in preference to a lower value unless convergence problems are encountered. The default value should be appropriate for most ‘stable’ networks. If it proves necessary to reduce the weighting factor, then tighter pressure and mass flow rate tolerances are required to achieve a similar level of accuracy. As a rule of thumb the pressure and mass flow rate tolerances should be halved for each 0.1 reduction in weighting factor. (For example, use tolerances of about 0.0125 % for a weighting factor of 0.3). In transient analyses, increasing weighting factor, to say 0.7, can help with rapid events. However, do not increase tolerances in transient analysis to improve convergence; it usually does the reverse. Nodal temperature tolerance checks work in the same way as for pressure. But unless the network comprises of closed loop systems (where an equilibrium temperature must be found) the calculated temperatures will follow directly from the mass flow and pressure solutions. If improved temperature accuracy is required it will often be better to tighten the mass flow tolerance - there is usually a better ‘feel’ for reasonable values for this quantity. The minimum heat flow tolerance is only used by ‘solid’ components (bars, bridges, temperature, heat sources etc.). The following flowchart shows how Flowmaster checks for convergence.

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Easy Guide - Convergence and Tolerance

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Valve Data Conversion & Validation

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Easy Guide - Valve Data Conversion & Validation When using valves with compressible flow, it may be necessary to convert manufacturer data for gas flow constants. This example demonstrates the relationship stated in DS Miller Internal Flow Systems (p168) and validates it on a simple network

Example A simple network has been constructed to validate the following relationship Av = 28 x 10-06 Kv, where Av=Flow Coefficient (m2) and Kv=European Flow Coefficient (m3/h)

Manufacture’s Supplied data: Kv vs. Valve Opening

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Using conversion Flow Coeff vs Valve Opening

Easy Guide - Valve Data Conversion & Validation From experimental results we know that at a Valve opening ratio of 60% open -> Kv = 0.002526, the change in pressure across the valve is about 5 bar. Results from compressible steady state run: Total pressure result in Flowmaster

Density results:

Velocity results:

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Easy Guide - Valve Data Conversion & Validation Inputting these values in to the equation

gives

which is approximately the value predicted by experiment.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Calculating Transient Time-Step

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Easy Guide - Calculating Transient Time-Step Flowmaster uses the method of Characteristics to solve for flows in elastic pipes. The method is applied to a spatially fixed grid where the number of grid elements, “S”, is given by S=

L aΔt

where L - Pipe Length, a = wave speed, Δt = time step

In order to work effectively, S must be ±0.2 of an integer greater than 3.

Example This example demonstrates how a simple network can be modified in order to optimise computational effort while still meeting the S criteria

The above pipes are 1000m and 675m long, applying the equation for S to this network gives

Schedule of Pipes

Δt1 = 0.1s

Δt2 = 0.02s

L (m)

a (m/s)

L/a (s)

S1

S2

Pipe 1

1000

1000

1

10

50

Pipe 2

675

1250

0.54

5.4

27

Δt = 0.02 s satisfies the criterion for S. This solution gives a large number of internal reach lengths and combined with the 3000 time-steps required to run the simulation for 60 seconds requires considerable computational effort.

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Easy Guide - Calculating Transient Time-Step

Length adjustment Pipe 2 is split into a 650 m elastic pipe and a 25 m rigid pipe. Δt1 = 0.1s

Schedule of Pipes L (m)

a (m/s)

L/a (s)

S1

Pipe 1

1000

1000

1

10

Pipe 2a

650

1250

0.52

5.2

Pipe 2b

25

RIGID

Δt = 0.1 s satisfies the criterion for S. The loss in accuracy of considering pipe 2 in two sections, one rigid and one elastic is within the overall accuracy of the method. Computational effort is reduced with fewer internal reach Iengths and 600 time-steps being required.

Wave speed adjustment The wave speed in pipe 2 is increased to 1300 mIs. Δt1 = 0.1s

Schedule of Pipes L (m)

a (m/s)

L/a (s)

S1

Pipe 1

1000

1000

1

10

Pipe 2

675

1300

0.519

5.19

Δt = 0.1 s satisfies the criterion for S. The loss in accuracy of considering the wave speed in pipe 2 to be 4% greater than that estimated is within the accuracy of wave speed prediction and the overall accuracy of the method. Computational effort is about equal to the length adjustment method.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Pump Sizing / Modelling a System Curve

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Easy Guide - Pump Sizing / Modelling a System Curve This example demonstrates how Flowmaster can be used to model the head loss created in a system and so be used to size a pump. The example below uses a very simple system based around a ball valve controlling flow to a downstream reservoir, but the method is applicable to all systems which require a centrifugal pump.

Example In order to size a centrifugal pump for a given network, it is necessary to simulate it over a range of flow rates. To do this, create a curve which encompasses the range of interest – in this case we know that the system in question will never have to deal with flows greater than 6 cubic metres a second

Connect this curve to an upstream flow source

Run the network for 60 seconds to cover the range of possible flow rates for the system. To create a system curve, select the flow rate results for the valve and click “X axis for plotting”

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Easy Guide - Pump Sizing / Modelling a System Curve Repeat the process for the pressure results from the node. The resulting curve illustrates the variation in system back pressure vs flow rate; i.e. it tells us the pressure that is required to overcome the frictional, head and terminal losses of the system for a given flow rate. By superimposing pump curves on the same axis (see below) it is possible to size the pump required by a particular system and choose its optimal running point, given by the intersection of the system and pump curves.

In the example below, two pumps are plotted along with the system curve (the purple line). The intersection of the system curve with each pump curve represents the point at which the energy provided by the pump matches that required by the system.

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Easy Guide - Pump Sizing / Modelling a System Curve Pump curves can be created in a manner similar to that described above: create a network with a nominal pump in the place of the variable flow source In this case, the valve will be slowly opened over 60 seconds simulating a range of system head losses.

By selecting the valve arm 2 flow rate result (select “x axis for plotting as before”) and the upstream node pressure, a pump curve showing the drop in back pressure with increasing flow rate can be achieved.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide Flow Balancing

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Easy Guide - Flow Balancing Flow Balancing is an analysis option within Flowmaster V7 that performs incompressible pressure loss calculations for individual components but allows flow rates for components to be specified as an input parameter.  The analysis calculates the pressure conditions at those components, referred to as balancing components, and reports results which allows the user to optimise components or set component data to achieve the desired flows.

Application Example

In the Fire Protection System above, water is pumped from a constant head reservoir by the fire water pump through a control valve and into a branched network of sprinkler nozzles. The required analysis is to calculate the orifice plate diameters that will achieve a specified flow rate through each sprinkler nozzle.

Example Data The example network data are shown in the tables below. In this example, the sprinkler nozzles are represented by a Discrete Loss and Constant Head Reservoir. The required flow rate through the nozzles is 7 litres per second (0.007m3/s).

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Easy Guide - Flow Balancing

Discrete Loss/Reservoir (Sprinkler Nozzles) Forward Loss Coefficient

5

Reverse Loss Coefficient

5

Cross-sectional Area

0.03m

Pipe Diameter

0.025m

Liquid level above base

0m

Base level above reference

0m

2

Pipe components All pipes

Diameter: 0.2m

Radial Pump Rated Flow

0.25m3/s

Rated Head

80m

Rated Speed

1450rpm

Rated Power

200kW

Initial Speed

1450rpm

Constant Head Reservoir Pipe Diameter

0.2m

Liquid level above base

5m

Base level above reference

-20m

Absolute Roughness: 0.05mm

Pipe 1, 11

Length: 20m

Pipe 2-3

Length: 10m

Pipes 4-10

Length: 2m

Ball Valves

0.2m

Valve opening

0 ratio (closed)

Orifice Plates

Valve opening

1 ratio (open)

Forward Loss Coefficient

5

Reverse Loss Coefficient

5

Cross Sectional Area

0.03m2

Pressure Source

Pipe Diameter

0.2m

Orifice Diameter

Not Set

Volumetric Flow Rate

0.007m3/s

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0.2m

Discrete Loss

Non Return Valve Diameter

Diameter

Total pressure

1 bar

Easy Guide - Flow Balancing

Orifice Plate Data Next let’s look at what data is required for the orifice plate to be defined.

As with all Flowmaster components the pink fields are mandatory. To size the orifice plate using Flow Balancing we need to enter the pipe diameter and the required Volumetric Flow Rate, in this case 0.2m and 0.007m3/s respectively. The value for the Orifice Diameter is left as ‘Not Set’ as it will be calculated in the analysis.

Analysis Type Once the model is complete, select the simulation tab and change the analysis type to ‘Incompressible Flow Balancing’ by selecting from the drop down menu. Then click run. Once completed, select the results tab and double click the result file you have just created.

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Easy Guide - Flow Balancing

Results Double click on one of the Orifice Plates to view the calculation data. In the Results view, the Flow Rate is shown as the required input value of 0.007m3/s, giving a calculated orifice diameter of 0.0169476m. The calculated operational values for the balancing components can now be updated in the Data tab view. Volumetric flow rate can be specified in most components, but it is most appropriate to components that can be set up to give the desired flow rate at the pressure conditions prevailing in the network.  The components most suited to the use of balancing flows are control valves, orifices, pipes, pumps, reservoirs and accumulators.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Incompressible Priming

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Easy Guide - Incompressible Priming Priming is an analysis option within Flowmaster V7 that can be used to simulate the process by which residual air has first to be exhausted from the pipes.

Application Example

In the Fire Protection System above, water is pumped from a constant head reservoir by the fire water pump through a control valve and into a hose (Priming Pipe). The required analysis is to calculate how long it will take the water to exit the hose end, i.e. how long it takes the water to fill the priming pipe.

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Easy Guide - Incompressible Priming

Example Data The example network data are shown below. Pipe components All pipes Diameter Absolute Roughness Wave Speed Pipes 8 & 10 Length Pipe 7 Length Pipes 5 Length

0.2m 0.05mm 1000m/s 2m 20m 100m

Radial Pump Rated Flow Rated Head Rated Speed Rated Power Pump Inertia Motor Inertia Speed Ratio Friction Torque Initial Speed

0.25m3/s 80m 1450rpm 200kW 50kgm2 25kgm2 1 500Nm 1450rpm

Non Return Valve Diameter 0.2m Characteristic Operating Time 0.5 s Minimum Velocity 2m/s Constant Head Reservoir Pipe Diameter Liquid level above base Base level above reference

0.2m 5m -20m

Ball Valves All Valves Diameter Valve 9 Valve Opening Valve 6 Valve Opening

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0.2m 1 ratio (open) 0 ratio (closed)

Easy Guide - Incompressible Priming Pressure Source Total pressure

1 bar

Discrete Loss Forward Loss Coefficient Reverse Loss Coefficient Cross Sectional Area

5 5 0.001m2

Valve Opening Tabular Controller 1st Time Valve Position at 1st Time 2nd Time Valve Position at 2nd Time 3rd Time Valve Position at 3rd Time

0s 0 ratio (closed) 2s 1 ratio (open) 1000 s 1 ratio (open)

Note: Nodes (8, 9 and 10) downstream of the opening valve should be set to compressible, i.e. all nodes in the priming section of the network. Changes to the type of node can be done in the node data form.

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Easy Guide - Incompressible Priming

Analysis Type Once the model is complete, select the simulation tab and change the analysis type to “7. Incompressible Priming” by selecting from the drop down menu. Enter the following values for simulation time and time step Time step 0.0005 s Simulation Start Time 0 s Simulation End Time 10 s Then click run. Once completed, select the results tab and double click the result file you have just created.

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Easy Guide - Incompressible Priming

Results In Results mode double click on component 8 Pipe: Cylindrical Elastic to view Results form. In the Results view, highlight Liquid Length, click Inspect... and select plot. The resulting plot will show you how the priming pipe filled and how long it took to achieve this.

The components that can be primed include Discrete Losses, Orifices, Pipes, Pressure Sources and Control Valves. Those that can not include Accumulators, Heat Exchangers, Bends, Diaphragms, Junctions, Transitions, Pumps, Reservoirs, Flow Sources, Flow v Pressure Sources, Check Valves and Weirs Many of the components that cannot be primed can still be used in the liquid section of the system.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide Defining a Fluid

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Easy Guide - Defining a Fluid

Fluid Properties ρ - Fluid Density (kg/m3) Cp - Constant pressure specific heat (J/(kg K) Cv - Constant volume specific heat (J/(kg K) γ - Ratio of specific heat (Cp/Cv) Z - Fluid compressibility factor μ - Dynamic viscosity (N s/m2) k - Thermal conductivity (W/m K) R - Gas constant (J/kg K)

Deduced properties c

- Sonic speed (m/s); Gradient (Compressibility factor variation with temperature); Gradient (Compressibility factor variation with pressure);

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Easy Guide - Defining a Fluid

There are three methods to defining a fluid within Flowmaster, they are as follows; 1. For an Isothermal analysis, the fluid can be defined at a single temperature. Data for the following properties is required

• • • • •

Reference temperature Vapour Pressure Reference Dynamic Viscosity Reference Density Bulk Modulus

2. For a temperature varying analysis, the fluid can be defined using fluid property versus temperature curves or equations. Data for the following properties is required

• • • •

Bulk modulus (can also be defined as a Bulk Modulus v Temp & Pressure surface) Vapour pressure v Temperature curve Viscosity v Temperature curve Density v Temperature curve

As an alternative to the curves the viscosity, density and specific heat capacity can be calculated by the following means: • • •

The viscosity can be calculated using the Walther Equation coefficients to effectively calculate a temperature v viscosity curve. (see Reference help > fluid properties) The variation of density with respect to temperature can be calculated using the thermal expansion coefficient and the reference and actual temperatures. The variation of specific heat capacity with respect to temperature can be calculated using the coefficients A to F in place of a curve.

3. Eagle Database Set the composition of the fluid using the eagle reference (maximum 5 different pure components), and also set the following;

• • • •

Equation of state Vapour Pressure Bulk Modulus Mole Fractions of fluid components.

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Easy Guide - Defining a Fluid

Standard Flowmaster Fluids

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Common Data Entry

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Easy Guide - Common Data Entry

Application Example

Consider the example above where all pipe diameters and valve diameters are to be the same. Rather than enter each data value individually you can enter the diameter into one component and then copy this value to all other selected components. First we must collect the components for which we want to enter a common diameter.

Collecting components When first building a network and a component is placed onto the schematic or a node is created, it is automatically listed in the Data pane in the component collection. When re-opening a network you can collect components and nodes in several ways;

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Easy Guide - Common Data Entry By right clicking on a component or node and selecting ‘Collect…’ Or by ‘rubber banding’ a selection of components and/ or nodes and then right clicking and selecting ‘Collect…’

By using the Add drop down menu and selecting all or specific components and nodes Or by double clicking on a component or node.

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Easy Guide - Common Data Entry

Data entry To enter a common diameter for all components in the collection, first select one of the components and in the lower pane click the Diameter entry field.

A drop down menu will automatically appear next to this cell allowing you to choose a unit for that value. The default unit is the one that is selected as such for that unit set.

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Easy Guide - Common Data Entry

Copying Data To copy a value from one component to another, the first step is to tick the box next to the desired value in the Copy column and then select the Copy icon in the top right of the lower pane.

This will open the Copy Features window where you can specify the copy function of your choice:

For example, if you want to copy the diameter from one pipe to the other, you can choose the Strict matching (matches component type and data field name), but if you want to copy it over to both the pipe and the valves, select ‘Relaxed’ matching (only matches data field name).

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.

Easy Guide

Composite Components

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Easy Guide - Application Example

Composite Components Using Flowmaster V7, a design engineer can combine several standard Flowmaster components to model complex geometries of individual components.

Application Example The following example is taken from the automotive industry and represents a silencer model for an automotive exhaust system.

Figure 1 Silencer model The model uses a combination of standard Flowmaster components including the Fixed Volume, Sharp Edge Orifice and Gas Accumulator components. Each is discussed briefly below.

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Easy Guide - Application Example

Fixed Volume Component The fixed volume component is basically a 2 arm-compressible accumulator that allows the user to model mass accumulation within a cavity that has both inflow and outflow through separate paths in the cavity. It also allows the user to set separate loss coefficients for the inlet and outlet of the volume. For this application we will be using several of these components to model the large volumes in the individual chambers of the silencer. We will set the diameters large and the loss coefficients small since we are using orifices and transitions to model the effects of the flow moving from one chamber to the next.

Sharp Edged Orifice The sharp edged orifice is a commonly used component in Flowmaster that models the pressure losses as the exhaust passes through small holes in the system. For the muffler in this model it will be used to model the openings between chambers where there is no piping involved. It is also used to model the exit losses of the muffler. The pipe diameter inputs for the orifice are set large to simulate the small hole in a relatively large plate.

Accumulator Gas This is the standard compressible accumulator component in Flowmaster. For this application we will be using these components to model the large volumes in the individual chambers of the silencer that have perforations to account for the volume and mass accumulation.

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Easy Guide - Application Example

Example Data The example network data are shown below. Components 1 and 2: Pipe: Cylindrical Gas Pipe Diameter

0.025 m

Pipe Length 1

0.1 m

Pipe Length 2

0.15 m

Friction Data Sub-form Friction Option

1 Colebrook White Approximation

Absolute Roughness

0.025 mm

Heat Transfer Sub-form No. of Internal Nodes

4

Components 3, 4 and 5: Fixed Volume Pipe Diameter 1

0.05 m

Pipe Diameter 2

0.05 m

Total Volume

0.001 m3

Inflow Loss Coefficient 1

1

Outflow Loss Coefficient 1

1

Inflow Loss Coefficient 2

1

Outflow Loss Coefficient 2

1

Polytropic Index 1

1.4

Polytropic Index 2

1.4

Component 6: Orifice: Sharp Edge

Component 7: Orifice: Sharp Edge

Pipe Diameter

0.03 m

Pipe Diameter

0.05 m

Orifice Diameter

0.02 m

Orifice Diameter

0.02 m

Components 8, 9, 10: Transition: Abrupt Major Diameter

0.05 m

Minor Diameter

0.025 m

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Easy Guide - Application Example Components 11 and 12: Accumulator Gas Inlet Pipe Diameter 11

0.015 m

Inlet Pipe Diameter 12

0.02 m

Accumulator Volume

0.003 m3

Initial Temperature

80°C

Initial Mass Flow Rate

0

Polytropic Charge

1.4

Polytropic Discharge

1.4

Pressure at Node level Pat_node_level =

Pstatic + Pdynamic

Or Pat_node_level =

Ptotal -

To validate the model, a pressure source is added at inlet and outlet and a Compressible Steady State simulation performed. Components 13 and 14: Pressure Source Total Pressure 13

4 bar

Total Pressure 14

1 bar

Once our model is confirmed we are then ready to create our data form for the composite component. There are several steps to doing this. These are listed below and we will discuss each step in detail.

• • • • • • • • • • •

Creating new composite framework Building the underlying model Setting configured values Assigning a symbol Deducing the connections Create signal mappings Creating data form Defining fall through values Hiding unwanted fields Defining call up values Testing completed composite component

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Easy Guide - Application Example

Creating new composite framework The first step is to define a new composite framework. This is done from the ‘Catalogue’ tab in the Project View as shown Figure 2. Expand the component family and right click on the ‘User Defined’ folder. Then select ‘New > Composite Component’. This will create an empty composite component under the User Defined folder and automatically open a composite schematic window as shown below.

Figure 2 Creating new composite This window will look very similar to the standard schematic window with one exception. The tabs in the Network View are different. They include Data, Connections and Data Model. These tabs will be where the customization of the component occurs. The first step is to rename the component. This is done by changing the name in the Property window in the lower left hand side of the screen. For our example change the name to Main Silencer.

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Easy Guide - Application Example

Building the Underlying model The next step is to create the model that will be underneath the composite component. This is the same model that we created above (without the pressure sources). We can either recreate the model from the beginning or we can simply copy and paste the components from our validation model. Once all the components have been added the schematic should look similar to Figure 3.

Figure 3 Underlying Model Note: If you are creating a composite component where the flow direction through the component is important, place the component that is intended to be the inlet of the composite into the schematic first. For this example it is component 1, the cylindrical pipe. This will be used later in the process for defining the component arms.

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Easy Guide - Application Example

Assigning a Symbol After you have created your network the next step is to assign a symbol to the composite. This is done from the Connections tab in the Network View selecting the Symbol button.

Figure 4 Connections tab This will open the symbol selection dialogue box. Within this window use the file browser to go to the User Defined Symbol Catalogue. This will list all of the symbols in this folder. By selecting any of the symbol names an image of the symbol will be displayed in the lower centre of the selection box. Once you have identified the appropriate symbol, choose the ‘Select’ button to attach it to your composite component. Once you have done this the symbol will appear in the ‘Connections’ tab just to the right of the ‘Symbol’ button.

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Easy Guide - Application Example

Figure 5 Selecting a Symbol

Deducing the connections Similar to standard Flowmaster components composite components have arms associated with the connection points of the components. These are the unconnected ends of the components in the network. Unlike standard components there is no limit to the number of arms that a composite component can have. To deduce the connections for your composite component select the Connections tab from your Network Views window. From this window select the ‘Deduce’ button as is shown in Figure 6.

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Easy Guide - Application Example

Figure 6 Deducing connections Flowmaster will evaluate the network and produce a connections map similar to the one below. This mapping shows that Arm 1 of the composite component is mapped to Arm 1 of component 1 (Pipe) and Arm 2 of the composite component is mapped to Arm 2 of component 7 (orifice).

Figure 7 Arm mappings Note: If components are added or removed from the schematic after the Arms are deduced this step must be repeated. Along with setting the arm mappings it also assigns a default placement for each of the arms of the composite component. This is the physical connection point with respect to the symbol. These are initially set to 16 for both arms and these must be changed to suit how the component is going to be used. This number can be set to any value between 0 and 59. These numbers are associated with a position on the symbol as is shown in the diagram below. Position 0 is the mid position on the left side of the symbol and they increase in a anti-clockwise manner around the symbol.

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Easy Guide - Application Example

Figure 8 Mapping Positions For our example, use placement value of 45 for Arm 1 and 15 for Arm 2. This will produce a symbol similar to that shown if Figure 9.

Figure 9 Main Silencer Connections

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Easy Guide - Application Example

Create Signal Mappings Many of the components have signal connections associated with them that the user may want to utilize as part of the composite component. To take advantage of these signal connections they must be mapped to the composite component. This is again done from the Network View window under the ‘Signal Mappings’ header.

Figure 10 Signal Mapping For our example we want to be able to get the pressure inside accumulator component 12 as a measurement output. Therefore we must map the measurement output of the accumulator to the Main Silencer composite. This is done by selecting the ‘Add’ button just above the Signal Mappings header. This will open a new window that lists all the components in the schematic that have signal connections. By selecting the ‘+’ next to the component, the window will expand to show all available connections for that particular component. These will either be designated with the letters (MO) for Measurement Output or (SI) for signal input.

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Easy Guide - Application Example

Figure 11 Signal Mapping Section For this example we expand component ‘12 Accumulator: Gas’ and it shows that it only has a Measurement Output. To proceed, check the box next to the Measurement Output. This will open an additional window which lists all of the variables that could be measured. Select Pressure and select the OK button. This will update the signal mapping window to show that pressure has been selected as the Measurement Output for that component. Now select OK in the Signal Mapping window and the Network View window will update to show that the measurement output mapping has been added to the composite component. Similar to the fluid connections, the placement of the signal connections on the symbol can be changed for this example change the placement to 50. If there are more signal connections desired for a composite component this process can be repeated.

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Easy Guide - Application Example

Figure 12 Signal Mapping and Placement

Setting Configured Values One of the major benefits of composite components is that they allow the user to predefine inputs for the underlying components that never change. This then eliminates the need for these values to be set every time the composite component is used. To do this it is important to understand how you will be using the component in the future and which inputs that you want predefined. You will only want to set configured values for items that will never change. For this example, we will pre-set the friction data in the pipes and the loss coefficients in the fixed volume components and polytropic index in fixed volume and accumulator components. This is done by simply setting the values in the individual components. Below are the values we will be using for each component. Components 1 and 2: Pipe: Cylindrical Gas

Friction Data Sub-form Friction Option

1 Colebrook White Approximation

Absolute Roughness

0.025 mm

Heat Transfer Sub-form No. of Internal Nodes

4

Logic: The pipe material will always be the same

Components 11 and 12: Accumulator Gas Initial Mass Flow Rate

0

Polytropic Charge

1.4

Polytropic Discharge

1.4

Logic: Pressure and Temperature changes will not be significant enough to affect the Polytropic Index.

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Easy Guide - Application Example Components 3, 4 and 5: Fixed Volume Pipe Diameter 1

0.05 m

Pipe Diameter 2

0.05 m

Inflow Loss Coefficient 1

1

Outflow Loss Coefficient 1

1

Inflow Loss Coefficient 2

1

Outflow Loss Coefficient 2

1

Logic: Using orifices and transitions to model the flow losses and velocity changes from 1 chamber to the next.

Polytropic Index 1

1.4

Polytropic Index 2

1.4

Logic: Pressure and Temperature changes will not be significant enough to affect the Polytropic Index.

Component 7: Orifice: Sharp Edge Pipe Diameter

0.05 m

Logic: Set large to simulate significant difference in the flow area to properly model the velocity changes. Components 8, 9, 10: Transition: Abrupt

Major Diameter

0.05 m

Logic: Set large to simulate significant difference in the flow area to properly model the velocity changes

Once these individual data items are set we are then ready to create our data form for the composite component.

Creating the Data Form Before creating the data form it is advantageous to look at all the data items that will need to be completed for all of the components and determine if any of them can be combined into a single item. Below is a list of components and the data items that need to be completed for each one of them. From this you can see that there are several fields that can be combined to reduce the total number of input fields from 20 to 14.

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Easy Guide - Application Example

Component

Data item

Same As Component No.

Custom Field Name

1 Pipe: Cylindrical Gas

Length

Unique

Inlet Pipe Length

1 Pipe: Cylindrical Gas

Diameter

2, 8,9,10 (minor dia.)

Pipe Diameter

2 Pipe: Cylindrical Gas

Length

Unique

Internal Pipe Length

2 Pipe: Cylindrical Gas

Diameter

1, 8,9,10 (minor dia.)

Pipe Diameter

3 Fixed Volume

Total Volume

Unique

Chamber 2 Volume

4 Fixed Volume

Total Volume

Unique

Chamber 3 Volume

5 Fixed Volume

Total Volume

Unique

Chamber 5 Volume

6 Orifice: Sharp Edge

Orifice Diameter

Unique

Internal Orifice Dia.

7 Orifice: Sharp Edge

Orifice Diameter

Unique

Exit Diameter

8 Transition: Abrupt

Minor Diameter

1, 2, 9, 10

Pipe Diameter

9 Transition: Abrupt

Minor Diameter

1, 2, 8, 10

Pipe Diameter

10 Transition: Abrupt

Minor Diameter

1, 2, 8, 9

Pipe Diameter

11 Accumulator: Gas

Pipe Diameter

Unique

Equiv. Flow Dia. Chamber 1

11 Accumulator: Gas

Total Volume

Unique

Chamber 1 Volume

11 Accumulator: Gas

Initial Temperature

12

Initial Temperature

12 Accumulator: Gas

Pipe Diameter

Unique

Equiv. Flow Dia. Chamber 4

12 Accumulator: Gas

Total Volume

Unique

Chamber 4 Volume

12 Accumulator: Gas

Initial Temperature

11

Initial Temperature

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Easy Guide - Application Example

Pipe Diameter

Diameter of all Pipes within the composite

Inlet Pipe Length

Length of pipe on the Inlet side of the silencer

Internal Pipe Length

Length of the pipe that is internal to the silencer

Chamber 1 Volume

Total volume in Chamber 1

Chamber 2 Volume

Total volume in Chamber 2

Chamber 3 Volume

Total volume in Chamber 3

Chamber 4 Volume

Total volume in Chamber 4

Chamber 5 Volume

Total volume in Chamber 5

Equivalent Flow Diameter Chamber 1

Equivalent diameter of all holes in the pipe through chamber 1 (inlet pipe)

Equivalent Flow Diameter Chamber 4

Equivalent diameter of all holes in the pipe through chamber 4 (internal pipe)

Internal Orifice Diameter

Diameter of orifice between chamber 2 and chamber 3

Exit Diameter

Diameter at the exit of the main silencer

Initial Temperature

Temperature inside the silencer at the start of the analysis

Now that we have determined all of the inputs that will be required for our silencer we are ready to build the data form.

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Easy Guide - Application Example To create the data form we must switch to the Data Model tab in the Network Views window and select the ‘Create/ Edit’ button as is shown below.

Figure 13 Creating Data Form This will then open the ‘Analytical Model Editor’. It is in this editor that we define each of the input fields and assign their context dependency. Using our list from the previous page we can begin to add the data items in the correct order. This is done by selecting the Add Existing button in the ‘Analytical Model Editor’ which will open the ‘Feature Selection’ window as is shown in Figure 14 and Figure 15 respectively.

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Easy Guide - Application Example

Figure 14 Analytical Model Editor

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Easy Guide - Application Example

Figure 15. Feature Selection Window Scroll down the list and find Pipe Diameter. You will see that there are multiple entries for many of the fields. This will allow you to use more than one instance of the input. You do need to be careful to ensure that they are input fields and not output fields though. This is shown in the lower left hand side of the window. Place a check mark next to the Pipe Diameter field and select OK. You will then see that this item has been added to the Analytical Model Editor. You will also see that the Necessity table on the right side of the editor now has several Simulation types visible. This portion of the editor is used to tell Flowmaster which fields are mandatory, optional or context dependent for each of the available analysis types. For the Main Silencer this will only be used in Compressible Steady State, Compressible Transient and Compressible Flow Balancing applications. For each of these simulation types set the requirement to Mandatory. This is done by selecting the drop down menu next to the analysis type.

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Easy Guide - Application Example

Figure 16. Simulation Type Necessity We now need to add the other required fields for our component. Repeat the process above and select the following fields and select the same necessity type for each: Inlet Pipe Length: Internal Pipe Length:

Inlet Pipe Length Length

Note: there is not a default field type for Internal Pipe Length so we chose an Equivalent field simply named Length.

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Easy Guide - Application Example

Figure 17. Necessity Types The next 5 fields are very similar in that they represent volumes in the different chambers in the Silencer. Flowmaster does not have 5 independent volume features in the standard database, but the Analytical Model Editor provides the capability to create new features in the database. This is done by selecting the Add New… button in the Features table. This will then open a series of windows that will step you through creating the new feature. The first of these is the Feature Type.

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Easy Guide - Application Example

Figure 18. Feature Type This window is used to select the type of feature we would like to add. For the Volume fields we want to use a Real data type, so this is selected and then press OK. This will then open the Feature Edit window. This window is used to create the following items for our example: • Feature Name : Volume 1 • Designate if it is an Input field or Output field : Input • Add any field specific help if required : NA • Specify the Units for the field : volume(m3) Once these items are entered select OK and set the Necessity values as we did before. Repeat this step for each of the volume fields for Volume 1 to Volume 5.

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Easy Guide - Application Example

Figure 19. Volume Fields We need to now add the 5 remaining fields. There are existing fields in the editor to accommodate these remaining fields. Use the Add Existing… button to include these remaining fields as per the list below. Equivalent Flow Diameter Chamber 1: Arm 1 Diameter Equivalent Flow Diameter Chamber 4: Arm 2 Diameter Internal Orifice Diameter: Orifice Diameter Exit Diameter: Diameter Initial Temperature: Initial Temperature Once these are all added select OK and return to the Data Model tab. You will be able to see all the data items that have been added to the composite.

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Easy Guide - Application Example

Figure 20 Data Model View of Input Fields

Customising Fields and Defining Fall Thru Values The next step is to create the custom names for each of the fields and defining how they are linked to the components within the composite components. First we will create the custom names where required. On page 25 of the application guide is list of all the input fields with a description of each field. Comparing that list to our input field names we can see that there are 10 of the 13 fields that we will want to create custom names for. Below is a summary of the fields and the custom names we have chosen. Internal Pipe Length: Length Chamber 1 Volume: Volume 1 Chamber 2 Volume: Volume 2 Chamber 3 Volume: Volume 3

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Easy Guide - Application Example Chamber 4 Volume: Volume 4 Chamber 5 Volume: Volume 5 Equivalent Flow Diameter Chamber 1: Arm 1 Diameter Equivalent Flow Diameter Chamber 4: Arm 2 Diameter Internal Orifice Diameter: Orifice Diameter Exit Diameter: Diameter To create the custom name select the Length input field in the Data Model tab. This will then display the properties of the field. These properties include Default Value, Minimum and Maximum Value and many others. The first property in the list is Custom Name. For the Length field add “Internal Pipe Length” as the value.

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Easy Guide - Application Example

Figure 21 Custom Names You will see the field name in the Data Model update. Repeat this for all the fields in the list. When you are finished the Input field list should be similar to the figure below.

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Easy Guide - Application Example

Figure 22 Custom names list Now that we have all of our custom names created we are ready to associate them to the components underneath the composite components. To do this we again look at the Data Model tab and expand the Parts list at the bottom of the window. This shows a list of all the components and nodes that are included in the composite component. Furthermore, if we expand any one of the components we can see all input and output fields that are associated with that particular component. It is here where we can now link the custom fields to the component fields. This is done by highlighting the custom field name and checking the appropriate field name under the individual components that you want to associate the custom field with. It is important to make sure that the “Check for Fall Thru” radio button is selected. It should also be noted that that multiple component fields can be associated with a single custom field.

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Easy Guide - Application Example

Figure 23 Field Mapping

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Easy Guide - Application Example Previously we defined field mappings which we can now use as a guide for mapping all of the fields. This table can be rearranged to clarify the mapping

Custom Field Name

Component

Data item

Pipe Diameter

1 Pipe: Cylindrical Gas

Diameter

2 Pipe: Cylindrical Gas

Diameter

8 Transition: Abrupt

Minor Diameter

9 Transition: Abrupt

Minor Diameter

10 Transition: Abrupt

Minor Diameter

Inlet Pipe Length

1 Pipe: Cylindrical Gas

Length

Internal Pipe Length

2 Pipe: Cylindrical Gas

Length

Chamber 1 Volume

11 Accumulator: Gas

Total Volume

Chamber 2 Volume

3 Fixed Volume

Total Volume

Chamber 3 Volume

4 Fixed Volume

Total Volume

Chamber 4 Volume

12 Accumulator: Gas

Total Volume

Chamber 5 Volume

5 Fixed Volume

Total Volume

Equivalent Flow Diameter Chamber 1

11 Accumulator: Gas

Pipe Diameter

Equivalent Flow Diameter Chamber 4

12 Accumulator: Gas

Pipe Diameter

Internal Orifice Diameter

6 Orifice: Sharp Edge

Orifice Diameter

Exit Diameter

7 Orifice: Sharp Edge

Orifice Diameter

Initial Temperature

11 Accumulator: Gas

Initial Temperature

12 Accumulator: Gas

Initial Temperature

The Figure below shows the proper mapping for the Inlet Pipe Length. We can see from the Table above that the Length of component no. 1 is the proper field to map. So first, highlight Inlet Pipe Length in the custom fields and then expand component 1 to show all the input fields. Flowmaster applies a sorting logic and inactivates any field that could not match the data type that you have chosen so it is easy to see that length is the only option for this component. Check the box next to Length.

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Easy Guide - Application Example

Figure 24 Inlet Pipe Mapping Repeat this for each of the items in the table and take care to include all the fields when one custom field has multiple entries.

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Easy Guide - Application Example

Defining Custom Result Fields and Mapping Pass Up Values Now that we have all of the input fields defined and mapped we want to determine what results from the individual components we want reported as a result for the composite component. By default Flowmaster will provide standard results for flow rate, pressures, and temperatures for the composite as whole so we need not be concerned about these. Note: If we are interested in a particular result internal to the composite such as a node pressure we must attach a gauge to the node and map the custom result to the result of the gauge. For our example we are only going to be concerned with the Gas Mass and Pressure in the chambers 1 and 4. Therefore we will have 4 custom result fields to create. To create these we again go to the Analytical Model Editor and add additional fields this time making sure all the fields are Output fields. Similar to the Inputs we will map these to existing fields in the database. Below are the fields that we will use. Gas Mass: Chamber Pressure: Cavity Gas Mass: Pressure:

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Chamber 1 Gas Mass Chamber 1 Pressure Chamber 2 Gas Mass Chamber 2 Pressure

Easy Guide - Application Example

Figure 25 Custom output fields Now that the custom result fields have been added we need to customize the names in the same manner as we did the input fields. Use the list above to create the custom names.

Figure 26 Custom names list The final step is to map the Pass Up values for the results. This is done in exactly the same manner as the inputs except select the “Check for Pass Up” radio button.

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Easy Guide - Application Example Select the custom result and the appropriate result for the underlying component. Below is a table that shows the correct mapping for our component.

Custom Field Name

Component

Data item

Chamber 1 Gas Mass

11 Accumulator: Gas

Gas Mass

Chamber 1 Pressure

11 Accumulator: Gas

Pressure

Chamber 2 Gas Mass

12 Accumulator: Gas

Gas Mass

Chamber 2 Pressure

12 Accumulator: Gas

Pressure

Figure 27 Mapping Pass-Up Values

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Easy Guide - Application Example

Testing Completed Composite Component Now that we have completed the Silencer composite component we want to verify that it is providing the same results as the network it is based on. We can do this by building a simple model and compare the results to those of the network in Appendix A. Create a network like the one below with the following inputs.

Figure 28 Test network Component 1: Main Silencer Pipe Diameter: 0.0250 m Inlet Pipe Length: 0.1000 m Internal Pipe Length 0.1500 m Chamber 1 Volume 0.0010 m3 Chamber 2 Volume 0.0010 m3 Chamber 3 Volume 0.0010 m3 Chamber 4 Volume 0.0030 m3 Chamber 5 Volume 0.0010 m3 Equivalent Flow Dia Chamber 1 0.0150 m Equivalent Flow Dia Chamber 4 0.0200 m Internal Orifice Diameter 0.0200 m Exit Diameter 0.0250 m

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Easy Guide - Application Example Initial Temperature 80.0 °C Component 2: Pressure Source Total Pressure:

1 Bar

Component 3: Pressure Source Total Pressure:

4 Bar

Now run a compressible steady state analysis and compare the results for the Chamber 1 gas mass and pressure with those same items for component 5 Accumulator: Gas and the results for Chamber 2 gas mass and pressure with component 6 Accumulator: Gas. If the composite is created correctly these results should match.

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©2014 Mentor Graphics Corporation, all rights reserved. This document contains information that is proprietary to Mentor Graphics Corporation and may be duplicated in whole or in part by the original recipient for internal business purposes only, provided that this entire notice appears in all copies. In accepting this document, the recipient agrees to make every reasonable effort to prevent unauthorized use of this information. All trademarks mentioned in this publication are the trademarks of their respective owners.