Lab Manual Thermal Science and Fluid Mechanics

Revision: September, 2014

INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

Department of Biochemical-Biotechnology Engineering

Lab Manual for

Biotechnology Engineering Lab II BTE 2222

Semester 1 (2014/2015)

PREFACE This course covers experiments in fluid mechanics and thermodynamics. Laboratory experiments are designed to provide hands-on experience to apply the engineering principles taught in lectures. In the fluid mechanics laboratory the experiments are: flow in pipes (determination of friction losses in straight pipes and in different pipe fittings), calculating flow rate using venturi and orifice meters and pumps in series/parallel. Thermo-fluid laboratory experiments are: vapour pressure of water at high temperature, heat capacity of gases, Joule-Thomson effect, thermal and electrical conductivity of metals, and heat pump. The objectives of this course are to: 1.

Elucidate how to extract the necessary information about the theory and procedure of an experiment from the laboratory manual.

2.

Enable to operate the various equipment and instrumentation to collect the data required to fulfill the objectives of each experiment.

3.

Analyze the data using the theory and experimental methods used and compare them with those available in the literature.

4.

Validate the theory using experimental results and understand the limitation of experimental results compared to prediction from theory.

5.

Prepare scientific reports following standard format.

6.

Develop the ability to work in a team.

Upon completion of this course, students should be able to: 1. Describe and apply the principles of mechanical energy balance in calculating friction losses, pressure drop and flow rate through straight pipes and fittings and flow devices 2. Study and distinguish different flow regimes and the law of conservation of momentum applied to flow in a straight conduits. 3. Measure and differentiate various thermodynamic properties of gases and vapours. 4. Perform experiment to measure the thermal and electrical conductivities of metals. 5. Demonstrate the second law of thermodynamics using a heat pump device.

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TABLE OF CONTENTS

CONTENTS

Page

Preface

1

Schedule of Experiment

3

Laboratory Safety Regulations

4

Workplace Hazardous Materials Information System

5

Guideline for Laboratory Reports

6

Marking Scheme for Laboratory Reports

7

Thermodynamics Experiments Experiment 1: Vapour Pressure of Water at High Temperature Experiment 2: Heat Capacity of Gases Experiment 3: Joule-Thomson Effect Experiment 4: Thermal and Electrical Conductivity of Metals Experiment 5: Heat Pump Fluid Mechanics Experiments Experiment 1: Friction losses in straight pipes, bends and elbows Experiment 2: Pumps in parallel and series Experiment 3: Reynolds Osborne Experiment 4: Flow rate measurements Experiment 5: Fan’s test Appendices A: Report Cover Page for Thermodynamics Experiments

45

B: Report Writing Guidelines for Thermodynamics Experiments

47

C: Report Cover Page for Fluid Mechanics Experiments

48

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SCHEDULE OF EXPERIMENT

TO BE ANNOUNCED AT THE BEGINNING OF EVERY SEMESTER

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LABORATORY SAFETY REGULATIONS GENERAL 1. Do NOT work with hazardous substances without a second person being present 2. Do NOT eat, drink or smoke in the laboratory under any circumstances 3. ALWAYS Keep your working area clean and tidy and free of clutter 4. ALWAYS Keep benches tidy and gangways clear 5. ALWAYS support gas cylinders, and ALWAYS close cylinder valves after use 6. ALWAYS label containers in plain English with the common known name of the substance and the appropriate hazard warning sign 7. ALWAYS secure the tops of reagent bottles immediately after use 8. ALWAYS work with fume cupboard sashes as low as possible and ALWAYS work towards the back of the cupboard 9. ALWAYS use double containment techniques where possible and drip trays to limit the consequences of a spillage 10. ALWAYS clear up spillages immediately 11. Do NOT leave equipment using water, gas or electricity on overnight without completing a “Silent Running” form, and ALWAYS ensure all water hoses are secured with jubilee clips PERSONAL PROTECTION 1. ALWAYS wear a lab coat and appropriate eye protection, e.g. safety spectacles, goggles or face shield. 2. Lab coats should ALWAYS be buttoned up and NOT worn in amenity areas of the University. 3. ALWAYS use the appropriate gloves whenever handling chemicals or hazardous substances, and ALWAYS check their integrity before use, ensuring they will give you protection against the substance being used 4. ALWAYS wear proper footwear, do NOT wear open toed footwear EMERGENCIES 1. ALWAYS know where your nearest fire extinguisher and first aid kit are 2. ALWAYS know your emergency escape route and assembly point STORAGE AND DISPOSAL 1. ALWAYS keep broken glassware and sharps separate from other waste and ALWAYS dispose of in the appropriate containers 2. ALWAYS return stock bottles/jars/dewar’s etc of highly flammable liquids or acids to their correct store cupboard after work has finished 3. Do NOT have more than 500 ml of a flammable solvent in use at any one time on the bench.

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WORKPLACE HAZARDOUS MATERIALS INFORMATION SYSTEM

It is important that All people in the laboratory develop the Know how to work safely and be ready to deal with accidents and emergencies should they occur. You don’t have to handle a controlled product to be put at risk. The hazards of dangerous chemicals can affect everybody, but becoming familiar with Workplace Hazardous Materials Information System (WHMIS) will allow you to protect your health.

CLASS A: COMPRESSED GAS This class includes compressed gases, dissolved gases, and gases liquefied by compression or refrigeration. Preventative Measures:  ensure container is always secured  store in upright position, chained or restrained in a cool, dry ventilated area  mark empty containers and store separately  use in well ventilated areas CLASS B: FLAMMABLE AND COMBUSTIBLE MATERIAL This class includes solids, liquids, and gases capable of catching fire in the presence of a spark or open flame under normal working conditions. Preventative Measures:  store in properly designated areas  work in well ventilated areas  avoid heating or other sources of heat, sparks, or flames  properly ground and bond containers when dispensing these liquids

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GUIDELINES FOR LABORATORY REPORT Thermodynamics All reports for thermodynamics part should be submitted two weeks after the experiment’s day (the next 2 Fridays when you are coming back for the following thermodynamics lab session). The report should be handed in to the demonstrator at the Thermal Science lab before the new experiment starts. Any late submission will not be entertained, unless they are concrete and unavoidable reasons. The report should be fully typed. The reports will not be returned to the students. Any students who wanted to check their report can do so with the instructor at his/her office. Fluid mechanics All reports for fluid mechanics part should be submitted one weeks after the experiment’s day (the next Friday). The report should be handed at the lecturer’s office before 3:00 pm. Any late submission will not be entertained, unless they are concrete and unavoidable reasons. The report should be fully typed. The reports will not be returned to the students. Any students who wanted to check their report can do so with the instructor at his/her office. Each experiment write-up contains a number of questions. These are to be answered in your Introduction or Theory or Discussion section. Any unanswered question might result a deduction of marks in your reports

LABORATORY REPORT FORMAT Title page Specify the experiment’s number and its title. Include names of all experimenters, experimenters’ matric numbers, experimenter’s programme (Biotechnology Engineering), laboratory name (Fluid mechanics or Thermodynamics) and section, date of submission, and dates when experiments were carried out. Refer to Appendix A for the example of this title page. This page should be typed in computer and printed. Objectives The objectives are a clear concise statement explaining the purpose of the experiment. The objectives serve as a guide to the results. This is one of the most important parts of the laboratory report because everything included in the report must somehow relate to the stated objectives. The objectives can be as short as one sentence and it is usually written in the past tense. Do not exceed one page. However, for this course you just have to copy from lab manual and rewrite it in your reports.

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Abstract/Introduction Summarize the important results. The abstract must be self-contained: do not refer to figures and tables located in other sections of the report. Do not include tables, figures, and equations, unless absolutely necessary. Do not assume that the reader will unambiguously identify undefined symbols. Be precise and succinct. Do not exceed one page. The Abstract should be written with great care because it is a most important part of the Final Report and will have a very large impact on the grade assigned to the work. Procedure The procedure section should contain a schematic drawing of the experimental setup including all equipment used in a parts list with manufacturer serial numbers, if any. Show the function of each part when necessary for clarity. Outline exactly step-by-step how the experiment was performed as there is someone desires to duplicate it. If it cannot be duplicated, the experiment shows nothing. Results Include all tables and graphs that document your final results. Include all relevant information so that you can later refer to these figures in the Discussion section to support your conclusions. If possible, present the results in the same order that you listed the objectives. Do not discuss the significance of the results. Include only final results that satisfy the objectives of the experiment; lengthier tables and intermediate figures should be included in the Appendix. Introduce the reader to each figure and table with a brief paragraph indicating what variables are plotted or tabulated. Each figure and table must have a unique number and a title or caption. Sample Calculations Give one example of each calculation that leads to a result reported in the document. Include one calculation for each figure or table reported in the Results section. Introduce each calculation with a brief paragraph indicating to the reader which specific point in a figure or entry in a table is being calculated. These calculations are samples only and must be annotated. Extensive calculations should be included in the Appendix; the Sample Calculations section can then include appropriate references to the Appendix. Discussion This section should give an interpretation of the results explaining how the object (The Objectives) of the experiment was accomplished. If any analytical expression is to be verified, calculate % error and account for the sources. (% error – An analysis expressing how favorably the empirical data approximate theoretical information. There are many ways to find % error, but one method is introduced here for consistency. Take the difference between the empirical and theoretical results and divide by the theoretical result. Multiplying by 100% gives the % error. You may compose your own error analysis as long as your method is clearly defined.) Discuss this experiment with respect to its faults as well as its

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strong points. Suggest extensions of the experiment and improvements. Also recommend any changes necessary to better accomplish the objectives. Use the available theory to explain why the relevant variables behaved in the observed fashion. (Each experiment write-up contains a number of questions. Some of these are to be answered or discussed in the Discussion and Conclusions section.) Conclusion Conclude and summarize the discussion. It should not contain any discussion on theory. Do not exceed HALF PAGE. References List all the literature sources that are cited in the report. You may refer this lab manual References for format reference. References: [1] Syed Noh, Fluid Mechanics Lab Manual, pp.10 - 11, IIUM Press, 2006 Appendix (1) Original data sheet. This original data sheet should be approved by the demonstrator(s) during the experiment day. (2) Calibration curves of instruments which were used in the performance of the experiment. Include manufacturer of the instrument, model and serial numbers. Calibration curves will usually be supplied by the instructor.

Graphs In engineering laboratory reports, one of the methods to represent the results is graph. The graph sometimes summarized the results. An acceptable graph has several features. Some of the important features are as following.       

Axis labels defined with symbols and units. Each line is identified using a legend. Data points are identified with a symbol: “x” on the Qac line to denote data points obtained by experiment. Data points are identified with a symbol: “o” on the Qac line to denote data points obtained by theoretical. Nothing is drawn freehand. Should have number and title; e.g. Fig. E1.1 Volumetric flow rate, Q vs. head drop, Δh. Title is descriptive, rather than something like Q vs Δh For non-computer generated graph, a graph paper must be used.

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THERMODYNAMICS EXPERIMENTS

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EXPERIMENT 1 Vapour Pressure of Water at High Temperature

Introduction In this experiment, water is heated in a closed pressure chamber; as much water vaporises as to make the pressure in the chamber correspond to the vapour pressure at the temperature at any time. The heat of vaporisation is determined at various temperatures from the measurement of vapour pressure as a function of temperature. The thermal energy which must be taken up by one mole of liquid, to vaporise at constant temperature is called the molar heat of vaporisation,  . At a given temperature there is a vapour pressure at which liquid and gaseous phase are in equilibrium. When a liquid boils the vapour pressure is equal to the external (atmospheric) pressure.

Objectives i) ii) iii)

To measure the vapour pressure of water as a function of temperature. To calculate the heat of vaporisation at various temperatures from the values measured. To determine boiling point at normal pressure by extrapolation.

Equipment High pressure vapour unit High conductive paste Heating apparatus Pipette, with rubber bulb, long Tripod base Bosshead Support rod

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Procedure i)

Set-up the experiment as shown in Fig. 1.1.

Fig. 1.1: Experimental set-up for measuring vapour pressure as a function of temperature ii) iii) iv) v) vi) vii) viii)

Fill the high pressure steam unit with distilled water, with the aid of a pipette, ensuring that there are no air bubbles in the line leading to the pressure gauge. Now carefully screw the vessel together. The unit is fastened with a bosshead and lies on the electric heater. Put the thermometer in the hole provided, which should be filled with head conductive paste. Heat the vessel until the gauge reads 3 MPa (30 bar). Now switch off the heater and record the pressure and temperature as equipment cools down in Table 1.1. Check the locking screws from time to time while the equipment is being heated and cooling down and tighten them if necessary.

Results and discussion The Clausius-Clapeyron differential equation

dp   … (1) dT T Vvap  Vliq .  where Vvap and Vliq are the molar volumes of vapour and liquid.

When the vapour behaves like an ideal gas and

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Vvap. 

R T … (2) p

where the universal gas constant, R = 8.3141

J , K  mol

therefore, (1) become

dp  dT   2 p R T

… (3)

Assuming  to be constant, by integrating we obtain the Van’t Hoff equation

ln p   i) ii) iii)

iv)

 1   const R T

… (4)

From the results obtained, calculate  for each set of pressure and temperature 1 From the results obtained, plot the graph of ln p vs. T From the slope of the graph, calculate the value of  . Then calculate the percentage difference between the value obtained from the graph and the values calculated earlier. By extrapolating the straight line in the lower region, determine the boiling temperature of water at normal temperature.

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Table 1.1: Experimental results Heat of vaporization (water)

 (˚C)

Pressure (Bar) Run #1

Run #2

Molar  (103 J mol-1) Average

30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

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EXPERIMENT 2 Heat Capacity of Gases

Introduction The first law of thermodynamics can be illustrated particularly well with an ideal gas. This law describes the relationship between the change in internal intrinsic energy ΔUi, the heat exchanged with the surroundings ΔQ, and the constant-pressure change pdV. dQ = dUi + pdV

…(1)

The molar heat capacity C of a substance results from the amount of absorbed heat and the temperature change per mole: C

1 dQ … (2)  n dT

n = number of moles One differentiates between the molar heat capacity at constant volume CV and the molar heat capacity at constant pressure Cp. According to equations (1) and (2) and under isochoric conditions (V const., dV = 0), the following is true: CV 

1 dUi … (3)  n dT

and under isobaric conditions (p = const., dp = 0): 1  dU dV  Cp   i  p  … (4) n  dT dT 

Taking the equation of state for ideal gases into consideration: pV = n R T … (5) it follows that the difference between Cp and CV for ideal gases is equal to the universal gas constant R.

Cp – CV = R … (6)

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It is obvious from equation (3) that the molar heat capacity CV is a function of the internal intrinsic energy of the gas. The internal energy can be calculated with the aid of the kinetic gas theory from the number of degrees of freedom, f: Ui 

1 fk B N ATn … (7) 2

where kB = 1.38 · 10-23 J/K (Boltzmann Constant) NA = 6.02 · 1023 mol-1 (Avogadro's number) Through substitution of R = kB NA … (8) it follows that CV 

f R … (9) 2

and taking equation (6) into consideration:  f  2 Cp    R … (10)  2 

The number of degrees of freedom of a molecule is a function of its structure. All particles have 3 degrees of translational freedom. Diatomic molecules have an additional two degrees of rotational freedom around the principal axes of inertia. Triatomic molecules have three degrees of rotational freedom. Air consists primarily of oxygen (approximately 20%) and nitrogen (circa 80%). As a first approximation, the following can be assumed to be true for air: f=5 CV = 2.5 R CV = 20.8 J · K-1 · mol-1 and Cp = 3.5 R Cp = 29.1 J · K-1 · mol-1.

Objective The experiment aims to determine the molar heat capacities of air at constant volume C v and at constant pressure Cp.

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Equipment Precision manometer Barometer/Manometer Digital counter Digital multimeter Aspirator bottle (10000 ml) Gas syringe (100 ml) Stopcock, 1-way and 3-way Rubber stopper, d = 32/26 mm, 3 holes Rubber stopper, d = 59.5/50.5 mm, 1 hole Rubber tubing, d = 6 mm Nickel electrode Chrome-nickel wire Push-button switch

Procedure Part A – Determining the Constant Value Cv i) ii)

iii) iv) v) vi)

The setup is as shown in Fig 2.1. To determine Cv, connect the precision manometer to the bottle with a piece of tubing. The manometer should be positioned exactly horizontally. Pressure increase has to be read immediately after the heating process. Begin the measuring procedure by pressing the push button switch. The measuring period should be less than a second. Take readings of the pressure (from the manometer), the current and voltage and record them in Table 2.1. Remove the air from the aspirator bottle after each measurement. Repeat steps iii) to v) in order to obtain 10 sets of results. Vary Δt within the given range.

Part B – Determining the Constant Value Cp i) ii)

iii) iv) v) vi)

The setup is as shown in Fig 2.2. Replace the precision manometer with two syringes which are connected to the aspirator bottle with the 3-way stopcock. One syringe is mounted horizontally, whereas the other syringe is mounted vertically with the plunger facing downwards. The vertical plunger is rotated before each measurement in order to minimize static friction. The air pressure is determined with help of the syringe scale. Take note of the initial volume of the syringe before performing the experiment. Begin the measuring procedure by pressing the push button switch. The measuring period should be less than a second but longer than 300ms. Take readings of the final volume (from the syringe), the current and voltage and record them in Table 2.2. Take readings up to 1 decimal point if possible as the difference is too small.

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vii) Remove the air from the aspirator bottle after each measurement and rotate the vertical plunger. viii) Repeat steps iv) to vii) in order to obtain 10 sets of results. Vary Δt within the range 300ms to 1s.

Results and discussion Part A – Determining the Constant Value Cv a) b)

c)

Plot a graph of pressure versus time. Calculate the slope of the graph. Given that, the indicator tube in the manometer has a radius of r = 2 mm and a pressure change of Δp = 0.147 hPa causes an alteration of Δl = 1 cm in length, calculate a. Corresponding change in volume is given as ΔV = a · Δp Calculate Cv.

where

po = 1013 hPa T0 = 273.2K V0 = 22.414 l/mol p = atmospheric pressure

The energy Q is supplied to the gas by the electrical heater:

Q  U  I  t where

U= the voltage which is applied to the heater wires I = the current, which flows through the heater wires t = the period of time in which current flowed through the wires

Part B – Determining the Constant Value Cp a)

Plot a graph of volume versus time. Calculate the slope of the graph.

b)

Calculate Cp, given the following information.

where

po = 1013 hPa T0 = 273.2 K V0 = 22.414 l/mol p = pa – pk pa = atmospheric pressure in hPa pk = pressure reduction due to weight of plunger

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pk 

Where

c)

mk  g FK

mk = 0.1139 kg = mass of the plunger g = acceleration of gravity FK = 7.55 x 10-4 m2 = area of the plunger

Calculate R. R = Cp – Cv

d)

Compare the calculated R to the literature.

Figure 2.1: Experimental setup for Part A

Figure 2.2: Experimental setup for Part B

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Part A – Determining the Constant Value Cv Table 2.1: Experimental results for Part A Time (ms)

Pressure (Bar)

Current (A)

Voltage (V)

Part B – Determining the Constant Value Cp Table 2.2: Experimental results for Part B Volume Time (ms)

Initial

Final

Difference

Current (A)

Voltage (V)

(by calculation)

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EXPERIMENT 3 Joule-Thomson Effect Introduction In real gases, the intrinsic energy U is composed of a thermokinetic content and a potential energy content: the potential of the intermolecular forces of attraction. This is negative and tends towards zero as the molecular distance increases. In real gases, the intrinsic energy is therefore a function of the volume, and:

During adiabatic expansion during which also no external work is done, the overall intrinsic energy remains unchanged, with the result that the potential energy increases at the expense of the thermokinetic content and the gases cools. At the throttle point, the effect named after Joule-Thomson is a quasi-stationary process. A stationary pressure gradient p2 – p1 is established at the throttle point. If external heat losses and friction during the flow of the gas are excluded, then for the total energy H, which consists of the intrinsic energy U and displacement pV:

In this equation, p1V1 or p2V2 is the work performed by an imaginary piston during the flow of a small amount of gas by a change in position from position 1 to 2 or position 3 to 4 (see Fig 3.1). In real gases, the displacement work p1V1 does not equal the displacement work p2V2; in this case:

Fig 3.1: Throttling and the Joule-Thomson effect

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Fig. 3.2: Temperature differences measured at various ram pressures.

This means that, from the molecular interaction potential, displacement work is permanently done and removed:

The Joule-Thomson effect is described quantitatively by the coefficients

For a change in the volume of a Van der Waals gas, the change in intrinsic energy is

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and the Joule-Thomson coefficient is thus

In this equation, cp is the specific heat under constant pressure, and a and b are the Van der Waals coefficients. If the expansion coefficients

are inserted, then

The measurement values in Fig. 3.2 give the straight line gradients

and

The two temperature probes may give different absolute values for the same temperature. This is no problem, as only the temperature difference is important for the determination Joule-Thomson coefficients. The literature values are

at 20˚C and 10-5 Pa,

at 20˚C and 105 Pa. For CO2, with a = 3.60 m6/ mol2 b = 42.7 cm3/ mol cp = 366.1 J/mol K

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the Van der Waals equation gives the coefficient

For air, with a = 1.40 m6/ mol2 b = 39.1 cm3/ mol cp = 288.9 J/mol K

the Van der Waals equation gives the coefficient

Objectives i) ii)

To determine the Joule-Thomson coefficient of CO2. To determine the Joule-Thomson coefficient of N2.

Equipment Joule-Thomson apparatus Temperature meter digital, 4-2 Temperature probe, immers. Type Rubber tubing, vacuum, i.d. 8mm Hose clip f. 12-20 diameter tube Reducing valve for CO2 / He Reducing valve for nitrogen Wrench for steel cylinders Steel cylinder rack, mobile Steel cylinder, CO2, 10 l, full Steel cylinder, nitrogen, 10 l, full

1 1 2 2 2 1 1 1 1 1 1

Procedure i) ii) iii) iv)

The set-up of the experiment is as in Fig 3.1. If necessary, screw the reducing valves onto the steel cylinders and check the tightness of the main valves. Secure the steel cylinders in their location Attach the vacuum between the reducing valve and the Joule-Thomson apparatus with hose tube clips.

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v) vi) vii)

On each side of the glass cylinders, introduce a temperature probe up to a few milimetres from the frit and attach with the union nut. Connect the temperature probe on the pressure side to inlet 1. Connect another temperature probe on the unpressurised side to inlet 2 of the temperature measurement apparatus. {PRINCIPLE OF THE EXPERIMENT: A stream of gas is fed to a throttling point, where the gas (CO2 or N2) undergoes adiabatic expansion. The differences in temperature established between the two sides of the throttle point are measured at various pressures and the Joule-Thomson coefficients of the gases in question are calculated.} Important Note: a) The experimenting room and the experimental apparatus must be in a thermal equilibrium at the start of the measurement. b) The experimental apparatus should be kept out of direct sunlight and other sources of heating and cooling. c) Set the temperature measurement apparatus at temperature difference measurement. d) Temperature meter should be switched on at least 30 min before performing the experiment to avoid thermal drift. e) Open the valves in the following order: steel cylinder valve, operating valve, reducing valve, so that an initial pressure of 100kPa is established. f) Reduce the pressure to zero in stages, in each case reading off the temperature difference five minute after the particular pressure has been established. g) Perform the measurement for both gases, and determine the atmospheric pressure and ambient temperature. Record all readings in Table 3.1 for CO2 and Table 3.2 for N2.

Fig. 3.1: Experimental set-up; Joule-Thomson effect

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Results and Discussion a) Plot ΔT versus p graph for both CO2 and N2. b) Determine μCO2 and μN2 from the gradient of the graph. c) Determine μCO2 and μN2 by calculation (for all available data). Use the following formula:

d) Calculate the percentage difference. Table 3.1: Temperature differences at various pressures for CO2 P (bar) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.00

T1 (K)

T2 (K)

ΔT (K)

Table 3.2: Temperature differences at various pressures for N2 P (bar)

T1 (K)

T2 (K)

ΔT (K)

0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.00

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EXPERIMENT 4 Thermal and Electrical Conductivity of Metals Introduction If a temperature difference exists between different locations of a body, heat conduction occurs. In this experiment there is a one-dimensional temperature gradient along a rod. The quantity of heat dQ transported with time dt is a function of the cross-sectional area a and the temperature gradient dT/dx perpendicular to the surface.

… (1)

where λ is the heat conductivity of the substance. The temperature distribution in a body is generally a function of location and time and is in accordance with the Boltzmann transport equation

… (2) where  is the density and c is the specific heat capacity of the substance. After a time, a steady state

… (3)

is achieved if the two ends of the metal rod having a length l are maintained at constant temperatures T1 and T2, respectively, by two heat reservoirs. Substituting equation (3) in equation (2), the following equation is obtained:

… (4)

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Objectives i) ii)

To determine the thermal conductivity of copper and aluminium is determined in a constant temperature gradient from the calorimetrically measured heat flow. To test the electrical conductivity of copper and aluminium is determined, and the Wiedmann-Franz law.

Equipment Calorimeter vessel, 500 ml Calor. vessel w. heat conduct. conn. Heat conductivity rod, Cu Heat conductivity rod, Al Magn. stirrer, mini, controlable Heat conductive paste, 50 g Gauze bag Rheostat, 10 Ohm , 5.7 A Immers.heater, 300 W, 220-250VDC/AC Temperature meter digital Temperature probe, immers. type Surface temperature probe Stopwatch, digital, 1/100 sec. Tripod base -PASSBench clamp -PASSSupport rod -PASS-, square, l 630 mm Support rod -PASS-, square, l 1000 mm Universal clamp Right angle clamp -PASSSupporting block 1053105357 mm Glass beaker, short, 400 ml Multitap transf., 14VAC/12VDC, 5A Digital multimeter Universal measuring amplifier Connecting cord, 500 mm, red Connecting cord, 500 mm, blue

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Procedure Part A – Heat Capacity of the Calorimeter i) ii) iii) iv) v) vi)

Weigh the lower calorimeter at room temperature Measure and record the room temperature. Prepare hot water and record its temperature. Pour the hot water into the lower calorimeter. Immediately take the temperature readings of the hot water in the calorimeter every 10 seconds for 5 minutes. Record them in Table 4.1. Reweigh the calorimeter to determine the mass of water.

Part B – Ambient Heat i) ii) iii) iv)

The calorimeter is then put under running tap water in order to get it back to room temperature. The calorimeter is then filled with ice water. With the assistance of ice, obtain water with a temperature of 0oC. When a temperature of 0oC is obtained, remove all the pieces of ice and record the temperature every minute for 30 minutes in Table 4.2. Reweigh the calorimeter to determine the mass of water.

Part C – Thermal Conductivity i)

ii) iii) iv) v) vi)

The setup is as shown in Fig 4.1. In this experiment, the differences in temperature between the upper and lower mediums are monitored, as well as the temperature of the water in the lower calorimeter. The empty lower calorimeter is weighed. Fill the lower calorimeter with ice water. With the aid of ice, obtain a temperature of 0oC. When a temperature of 0oC is obtained, pour hot water in the upper calorimeter. Ensure that the upper calorimeter is well filled with hot water. Keep the temperature of water in lower calorimeter water at 0oC with the help of ice, until the difference in temperature between two points on the rod, is steady. When a constant temperature gradient is obtained, remove all the ice in the lower calorimeter and begin taking readings of the difference in temperature and the temperature of the water in the lower calorimeter. Readings should be taken every 30 seconds for 5 minutes and record them in Table 4.3.

Part D – Electrical Conductivity i) ii) iii)

The setup is as shown in Fig 4.2. The metal rod in the setup is aluminium. Ensure that the voltage on the variable transformer is set to 6V. The amplifier must be calibrated to 0 in a voltage-free state to avoid a collapse on the output voltage. Select the following amplifier settings: Input Low Drift Amplification

104

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Time Constant iv) v) vi)

0

Set the rheostat to its maximum value and slowly decrease the value during the experiment. Collect readings of current and voltage for six rheostat settings (Table 4.4). Repeat steps i) to v) with the copper rod from the Part B and record all readings in Table 4.5.

Fig. 4.1: Experimental Set-up for Thermal Conductivity

Fig. 4.2: Experimental Set-up for Electrical Conductivity

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Results and discussion Part A – Heat Capacity of the Calorimeter Hot water temperature before poured into calorimeter = ____________ Calorimeter Temperature (assume same to Room Temperature) = ___________ Table 4.1 Hot Water Time (seconds) Temperature (oC) Time (seconds) Temperature (oC) 0 160 10 170 20 180 30 190 40 200 50 210 60 220 70 230 80 240 90 250 100 260 110 270 120 280 130 290 140 300 150

Part B – Ambient Heat

Time (mins) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Table 4.2 Cold water Temperature (oC) Time (mins) 0 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Temperature (oC)

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Part C – Thermal Conductivity

Time (seconds) 0 30 60 90 120 150 180 210 240 270 300

Table 4.3 Water Temperature (oC) 0

ΔT (oC)

Part D – Electrical Conductivity

Reading 1 2 3 4 5 6

Reading 1 2 3 4 5 6

Table 4.4 Aluminium Current (A)

Voltage (V)

Table 4.5 Copper Current (A)

Voltage (V)

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Part A – Heat Capacity of the Calorimeter i) ii)

From the results obtained, plot a graph of temperature vs. time. The temperature of the mixture,  m , is determined from extrapolating the plotted curve, as sketched in figure below. The straight line parallel to temperature axis was drawn such that the shaded parts are equal in area.

u = Temperature of the surrounding atmosphere 1 = Initial temperature  m = Temperature of mixture iii)

Calculate the heat capacity of the calorimeter using the following equation:   M C  c w  mw  w M  R where cW = Specific heat capacity of water

mW = Mass of the water

W = Temperature of the hot water  M = Mixing temperature  R = Room temperature

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Part B – Ambient Heat i)

Calculate the addition of heat from the surroundings.

Q  (cW  mW  C )  T ii) iii) iv)

ΔT = T – T0 , (T0 = Temperature at time t = 0)

where

Draw a graph of temperature vs time for the cold water. Draw a graph of heat from surroundings vs time. Calculate the slope for the graph which will give you dQ/dtambient.

Part C – Thermal Conductivity i)

ii)

iii)

Calculate Q and draw the graph of Q vs. t. Find the slope of this graph, which will dQ give you ambient.+ metal. dt dQ Calculate metal, given that: dt dQ dQ dQ metal = ambient.+ metal ambient dt dt dt Given the length of the rod as 31.5 cm and the area as 4.91x10-4 m2, calculate the heat conductivity of the rod, λ. dQ T  A  dt x

Part D – Electrical Conductivity i)

Calculate the electrical conductivity using the following equation:

ii)

The Wiedmann-Franz Law is as stated below:



l A R

  LT  Calculate the Lorenz number in each case. iii)

Given that the value of L is as follows, calculate the error in each case.

L

 2 k2 

2

 2.4 10 8

3 e where k – Universal gas constant = 1.38 · 10-23 J/K e – Elementary unit charge = 1.602 · 10-19 AS

W K2

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EXPERIMENT 5 Heat Pump Introduction Pressures and temperatures in the circulation of the electrical compression heat pump are measured as a function of time when it is operated as a water-water heat pump. The energy taken up and released is calculated from the heating and cooling of the two water baths. When it is operated as an air-water heat pump, the coefficient of performance at different vaporizer temperatures is determined. The Mollier (h, log p) diagram, in which p is the pressure and h the specific enthalpy of the working substance, is used to describe the cyclic process in heat technology. Fig. 5.1 shows an idealized representation of the heat pump circuit. The curve running through the critical point K delineates the wet vapor zone in which the liquid phase and gas phase coexist. In this zone the isotherms run parallel to the h axis. Starting from point 1, the compressor compresses the working substance up to point 2; in the ideal case this action proceeds without an exchange of heat with the environment, i.e. isentropically (S = const.). On the way from point 3 useful heat is released and the working substance condenses. Then the working substance flows through the restrictor valve and reaches point 4. In an ideal restricting action the enthalpy remains constant. As it passes from point 4 to point 1, the working substance takes up energy from the environment and vaporises. The specific amounts of energy q0 and q taken up and released per kg and the specific compressor work w required can be read off directly as line segments on the graph. q0 = h1 – h3 q = h2 – h3 w = h2 – h1 For evaluation purposes the data for the working substance R 134a in the wet vapor zone are set out in Table 5.1.

Figure 5.1: h, log p diagram of a heat pump, ideal curve.

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Table 5.1

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Objectives i)

ii)

iii)

Water heat pump: To measure pressure and temperature in the circuit and in the water reservoirs on the condenser side and the vaporizer side alternately. To calculate energy taken up and released, also the volume concentration in the circuit and the volumetric efficiency of the compressor. Air-water heat pump: To measure vaporizer temperature and water bath temperature on the condenser side under different operating conditions on the vaporizer side, i.e. Natural air, cold blower and hot blower. To determine the electric power consumed by the compressor and calculate the coefficient of performance.

Equipment Heat pump, compressor principle Lab thermometer, -10…+100C Lab thermometer, w. stem, -10…+110C Heat conductive paste, 50 g Hot-/Cold air blower, 1000 W Stopwatch, digital, 1/100 sec Tripod base -PASSSupport rod -PASS-, square, l 250 mm Universal clamp with joint Glass beaker Glass rod

Procedure Part A – Water-water Heat Pump i) ii) iii)

Pour 4.5L of water into the two water reservoirs. Record all the initial pressures and temperatures before switching on the heat pump. Start the stopwatch at the same time the heat pump is switched on. Record the power reading and the pressure and temperatures on both the vaporizer and condenser side every minute for approximately 20 minutes (Table 5.2).

Part B – Air-water Heat Pump i) Remove the water reservoir on the vaporizer side and dry the heat exchanger coils. ii) Obtain a temperature of 20oC for the 4.5L water on the condenser side. iii) Record all the initial pressures and temperatures before switching on the heat pump. iv) Start the stopwatch at the same time the heat pump is switched on. Record the power reading, and the temperatures at the vaporizer outlet and condenser water temperature, every minute for approximately 20 minutes (Table 5.3). v) Repeat steps ii to iv but with a hot blower and a cold blower approximately 30cm away.

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Results and discussion Part A – Water-water Heat Pump

Time (min)

Power (W)

P1

Table 5.2 Condenser θ1 θci θco

P2

Vaporiser θ2 θvi

θvo

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

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Part B – Air-water Heat Pump

Time (min)

Natural Air Power θ1 θvo (W)

Table 5.3 Hot Blower Power θ1 θvo (W)

Cold Blower Power θ1 θvo (W)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

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Part A – Water-water Heat Pump i)

Plot a graph of temperature vs. time for all inlet and outlet.

ii)

Calculations at t = 10mins:

 Q  c  m  t   c  m   Condenser heat flow, Q

2

a) Vaporizer heat flow,

o

b)

w

w

1

t

c) Average compressor power, P d) Performance at the condenser side,  

Q P

Q 0 e) Volume flow at the vaporizer side, V  v  h1  h3 (v = specific volume of the vapour) f) Geometrical volume flow, Vg  V g  f Given Vg = 5.08 cm3 f = 1450 min-1 g) Volumetric efficiency of the compressor,  

V Vg

Part B – Air-water Heat Pump i) ii) iii) iii) iv)

Plot a graph of temperature versus time for all the results. Calculate the average vaporizer temperature. Calculate the condenser heat flow. Calculate the performance. Compare the results for all the conditions and discuss.

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FLUID MECHANICS EXPERIMENTS

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ESSENTIAL CONCEPTS OF FLUID MECHANICS The objective of this section is to give an essential idea about Fluid Mechanics that students need to know before they start to perform an experiment. This section will be divided into three major subsections which is ‘Fluid Properties’, ‘Fluid Visualization’ and ‘Basic Governing Equation for Fluid Flow’. The way it is written is very brief so that students may need to refer to their reference book(s) in order to get more explanation. The suggested references are given at ‘References’. Fluid Properties 1. Measure of Fluid Mass and Weight 1.1. Density,  1.1.1. Is defined as mass per unit volume 1.1.2. Liquid have small effects of pressure and temperature while gaseous are strongly influenced by the change of pressure and temperature 1.1.3. For ideal gas, we can relate density with pressure and temperature by using ideal gas law 1.2. Specific Weight, γ 1.2.1. Is defined as weight per unit volume 1.3. Specific Gravity, SG 1.3.1. Is ratio of the density of the fluid to the density of water at some specified temperature (usually at 4°C)

2. Viscosity 2.1. Describe the “fluidity” of the fluid 2.2. It also indicates the internal resistance of the fluid to a motion 2.3. Also shows tendency of a fluid to stick to other substance or other fluid

2.4. Fluid that the shearing stresses are linearly related to the rate of shearing strains is called as Newtonian Fluid while fluid behave oppositely is known as Non-Newtonian Fluid 2.5. Non-Newtonian fluid can generally be classified to three type which is Bingham Plastic (e.g. toothpaste), shear thickening fluid (e.g. starch) and shear thinning fluid (e.g. paint) 2.6. Dynamic viscosity usually referred to as viscosity only 2.7. Kinematic viscosity is the ratio of viscosity (dynamic viscosity) to the density of the fluid.

3. Pressure 3.1. Is defined as force per unit area. 3.2. Pressure at a point in a fluid at rest, or in motion, is independent of direction as long as there are no shearing stresses present. 3.3. Pressure decreases as we move vertically upward in a fluid at rest. 3.4. For incompressible fluid 3.4.1. Pressure variation in an incompressible fluid is shown as

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3.4.2. Pressure head is a height of a column of fluid of specific weight, γ required to give pressure, P or pressure difference P1-P2.

3.5. For compressible fluid 3.5.1. Integrate equation of motion for fluid at rest to obtain pressure variation within compressible fluid.

3.5.2. In integrating this equation, we need to know how the density, thus specific weight, changes with elevation change. 3.6. Manometer 3.6.1. Piezometer

3.6.2. U-tube manometer

3.6.3. Inclined tube manometer

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3.7. Designation of pressure 3.7.1. Absolute pressure 3.7.1.1. Measured pressure relative to the perfect vacuum pressure (absolute zero pressure) 3.7.1.2. Have only positive value 3.7.2. Gage pressure 3.7.2.1. Measured pressure relative to the local atmospheric pressure 3.7.2.2. Have positive or negative value which indicates either larger or smaller than local atmospheric pressure.

Fundamental of Fluid Visualizations 1. Streamline 1.1. A streamline is a curve that is everywhere tangent to the instantaneous local velocity vector.

1.2. Streamlines (solid black curves) for the steady, incompressible, two-dimensional velocity field; where the velocity given by and velocity vectors (pink arrows) are superimposed for comparison. 2. Streak Line 2.1. A streakline is the locus of fluid particles that have passed sequentially through a prescribed point in the flow. 2.2. A streakline is formed by continuous introduction of dye or smoke from a point in the flow. Labeled tracer particles (1 through 8) were introduced sequentially.

3. Timeline 3.1. A timeline is a set of adjacent fluid particles that were marked at the same (earlier) instant in time. 3.2. Timelines are formed by marking a line of fluid particles, and then watching that line move (and deform) through the flow field; timelines are shown at t = 0, t1, t2, and t3.

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4. Path Line 4.1. A pathline is the actual path traveled by an individual fluid particle over some time period. 4.2. A pathline is formed by following the actual path of a fluid particle.

5. Streamlines, Streaklines and Pathlines for steady flow

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Basic Governing Equation for Fluid Flow 1. Control mass 1.1. mass of matters chosen for analysis 1.2. mass is absolutely not allow to move across the boundary but energy maybe move across 1.3. if the energy also not allow to move across then we call it as isolated control mass 2. Control volume 2.1. region in space that been chosen for analysis purpose 2.2. mass and energy allowed to move across it boundary or control surface. 3. Conservation of Mass 3.1. For a mass of a system, conservation of mass states that the time rate of change of mass of system is equal to zero. 3.2. For a control volume, it states that the time rate of change of the mass of the contents of the control volume plus the net rate of mass flow through the control surface must equal zero.

3.3. For steady, incompressible flow, the equation reduced to A1V1 = A2V2, where A is the cross section area and V is the flow velocity. 4. Conservation of Linear Momentum (Newton’s 2nd Law) 4.1. For a system, the conservation of linear momentum follows the Newton 2nd Law which states that time rate of change of the linear momentum of the system is equal to the sum of external forces acting on the system 4.2. For a fixed and non deforming control volume, the conservation of linear momentum states that the sum of external forces acting on the control volume is equal to the sum of the two control volume quantities: the time rate of change of the linear momentum of the contents of the control volume, and the net rate of linear momentum flow through the control surface.

5. Conservation of Energy (First Law of Thermodynamics) 5.1. The first law of thermodynamics for a system, in words, stated that the time rate of increase of the total stored energy of the system is equal to sum of the net time rate of energy addition by heat transfer into the system and the net time rate of energy addition by work transfer into the system.

where e is energy per unit mass. 5.2. For a control volume it states that, the sum of the time rate of the total stored energy of the contents of the control volume and the net rate of flow of the total stored energy out of the control volume through the control surface is equal to the sum of the net time rate of energy addition by heat transfer into the control volume and the net time rate of energy addition by work transfer into the control volume.

5.3. In application of this equation, it needs careful interpretation and consideration of each term. 5.4. Work can be transferred by 5.4.1. moving shaft or shaft work Biotechnology Engineering Lab II Manual 7

5.4.2. force associated with fluid normal stress 5.4.3. force associated with fluid tangential stress 5.5. For flow where the work by tangential force is zero,

5.6. Extended Bernoulli Equation (steady-in-the mean-flow, one dimensional flow)

or

where

and

5.7. Modified Bernoulli equation where no shaft work involves in the steady one dimensional flow.

or

with

5.8. Bernoulli equation

6. Bernoulli equation 6.1. Restriction 6.1.1. One dimensional flow or applicable along a streamline 6.1.2. Incompressible flow 6.1.3. Inviscid flow or frictionless flow 6.1.4. Steady flow 6.1.5. No shaft work involves

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6.2. Pressure terms

6.2.1. The first term is called static pressure or the actual thermodynamics pressure 6.2.2. Second term is called dynamic pressure 6.2.3. Third term is called hydrostatic pressure 6.2.4. The fourth term is the total pressure 6.2.5. The summation of dynamic and static pressure is called stagnation pressure where the velocity at that point is equal to zero

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EXPERIMENT #1 FRICTION LOSSES 1.1: IN STRAIGHT PIPES

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1.2: FRICTION LOSSES IN PIPES CONSISTING OF BENDS AND ELBOWS

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QUESTIONS 1. Derive Bernoulli Equation from the First Law of Thermodynamics. During the derivation, state all assumption and consideration clearly. 2. What are the Hydraulic Grade Line and Energy Grade Line? How the two lines relates to each other? How the two lines relates with Bernoulli Equation? 3. What is the restriction of Bernoulli Equation? 1. By using all answers for the questions above, explain what you should do in the experiments in order to achieve the objectives. 2. Derive Extended Bernoulli Equation and Modified Bernoulli Equation from the First Law of Thermodynamics. What are the different between the two equations? 3. What are major losses, minor losses and head loss? 4. What is the equation to determine head loss for straight pipe? 5. For a system with a constant diameter of straight pipe and not involving any pump work, how can we determine the head loss? 6. What is the friction factor? How we can determine it experimentally? How it change with Reynolds Number? 7. What is Moody Diagram? What we can obtain from it? 8. What is equation to determine head loss for minor losses? 9. For a system with one bend and not involving any pump work, how we can determine the head loss for the bend? 10. What is loss coefficient? What is equivalent length? How the two relates? 11. For a system (in a horizontal plane) consist of 2 similar elbows and 3 straight pipes with a constant diameter and having same length as shown in the Fig. Q9.

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Elbow with equivalent length Le

Elbow with equivalent length Le

Fig. Q9 Explain how we can determine the head loss for the system and show that we can determine the friction factor for the system if we apply the Modified Bernoulli Equation to the system 12. How we can determine pressure drop from the head loss?

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EXPERIMENT # 2 PUMPS IN SERIES & PARALLEL OBJECTIVES The objectives of the experiment are: 1. To demonstrate pump performance when connected in series and parallel 2. To show shut off point of pump in series and parallel LEARNING OUTCOMES It is expected by completing the experiment, the students will be able: 1. To estimate power requirement for a pump as a function of its throughput, pressure increase and efficiency 2. To analyze pump network for pipelines operating under pressure THEORY/BACKGROUND {More in reference book [1] section 14-2} In selecting a pump fro a given situation, we have a variety of pumps to choose among. The manufacturers provide the pump performance information such as the pump performance curves. The engineer’s task is to the pump or pumps that best fits in with the system characteristics. One of the considerations in fulfilling a system characteristic is whether to combine a pump in one system or not. The combination may be in parallel or series. By examining pump performance curve for pumps in series and pumps in parallel, we easily can say that the pumps in series tend to increase head but pumps in parallel tend to increase capacity. For this experiment, 1. Determine: a. Average velocity of the fluid flow b. Required net head by solving energy equation c. Pump efficiency 2. Plot on the same set of axes the graph of available net head, pump efficiency and required net head as a function of capacity (volumetric flow rate). 3. From the graph, determine (if possible) a. Shut off head for each pump b. Free delivery c. Best efficiency point d. Operating point EQUIPMENT Pump in Series and Parallel Apparatus PRECAUTIONS ON HANDLING EQUIPMENT 1. Never operate the pumps when there is no liquid in the pipeline. It will cause serious damage to the pumps. 2. Do not operate pump above and below its limit operation as given below: ORIENTATION Single Series Parallel

MINIMUM FLOW RATE (L/min) 20 20 40

MAXIMUM FLOW RATE (L/min) 90 90 180

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QUESTIONS 1. Explain the purpose to connect pump in series and parallel. 2. How would the performance curve for pump in series or parallel differ with single pump? 3. Illustrate the performance curve for pumps in series and single pump in one figure and pumps in parallel and single pump in another figure. 4. What is shut off point? What should we do at shut off point? 5. How we can determine shut off point? 6. Two reservoirs A and B are connected with a long pipe that has a characteristics such that the head loss through the pipe is expressible as hL=20Q2, where hL is in feet and Q is the flow rate in 100s of gpm. The water-surface elevation in reservoir B is 35 ft above that in reservoir A. Two identical pumps are available for use to pump the water from A to B. The characteristic curve of each pump when operating at 1800 rpm is given in the following table Operation at 1800 rpm Head, ft 100 90 80 60 40 20

Flow rate, gpm 0 110 180 250 300 340

Table E6.1 At the optimum point of operation, the pump delivers 200 gpm at a head of 75 ft. Determine the flow rate under the following conditions i. A single pump operating at 1800 rpm ii. Two pumps in series, each operating at 1800 rpm iii. Two pumps in parallel, each operating at 1800 rpm What happen if the elevation different between reservoir A and B is greater than 100 ft? 7. Repeat question (1.) if reservoir B is 20 ft below reservoir A and compare with the previous answer. Give your opinion upon the comparison. 8. Repeat question (1.) with the pumps operating at 1500 rpm. Compare the answer and discuss it. Operation at 1500 rpm Head, ft 83.33 75.00 66.67 50.00 33.33 16.67

Flow rate, gpm 0.00 76.39 125.00 173.61 208.33 236.11

Table E6.2 9. For situation in question (1.), determine the flow rate under the following conditions i. Two pump in series, one operating at 1800 rpm and another is 1500 rpm ii. Two pump in parallel, one operating at 1800 rpm and another is 1500 rpm Where is the shut off point for both combinations? 10. By using all answers for the questions above, explain what you should do in the experiments in order to achieve the objectives.

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REFERENCES [1] Yunus A. Cengel and John M. Cimbala, Fluid Mechanics: Fundamentals and Applications, McGraw-Hill, 2006. [2] Bruce R. Munson, Donald F. Young and Theodore H. Okiishi, Fundamentals of Fluid Mechanics, 5th ed., Wiley Asia Student Edition, 2006. [3] Clayton T. Crowe, Donald F. Elger and John A. Roberson, Engineering Fluid Mechanics, 8th ed., Wiley, 2005 [4] E. John Finnemore and Joseph B. Franzini, Fluid Mechanics with Engineering Applications, 10th ed., International Edition, McGraw Hill, 2006. [5] Robert W. Fox and Alan T. McDonald, Introduction to Fluid Mechanics, 5th ed., Wiley.

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EXPERIMENT # 3 REYNOLDS OSBORNE EXPERIMENT OBJECTIVES The objectives of the experiment are: 1. To demonstrate laminar, transition and turbulent flow 2. To introduce Reynolds number to classify laminar, transition and turbulent flow LEARNING OUTCOMES It is expected by completing the experiment, the students will be able: 1. To describe laminar, transition and turbulent flow 2. To determine critical Reynolds number for laminar, transition and turbulent flow THEORY/BACKGROUND {More in reference book [1] section 8-2} Fluid flow can be classified to three regimes which is laminar, transitional and turbulent regime. Laminar regime is a regime where the flow is characterized by smooth streamlines and highly ordered motion. Turbulent is a regime where flow is characterized by velocity fluctuations and highly disordered motion. Transitional regime is where the flow fluctuates between laminar and turbulent before it becomes fully turbulent. The transitional from laminar to turbulent flow depends on geometry, surface roughness, flow velocity, surface temperature, and type of fluid. However, Osborne Reynolds discovered that the flow regime mainly depends on the ratio of inertial forces to viscous forces. This ratio is what we called as Reynolds number. At small or moderate Reynolds numbers the viscous forces are large enough to suppress theses fluctuations and to keep the fluid “in line”. Thus, the flow is streamlined and in ordered motion. However, at large Reynolds numbers, the inertial forces, which are proportional to the fluid density and the square of the fluid velocity, are large relative to the viscous force. As the results, the viscous force cannot prevent the random and rapid fluctuations of the fluid. Thus, the flow will be in disordered motion. The boundary of Reynolds number for laminar, transitional and turbulent regime varies by geometries and flow condition. For example, flow in a circular pipe is laminar for Reynolds number less than 2300, turbulent for Reynolds number larger than 4000 and transitional in between. However, we will have other boundaries if the pipe cross sectional area is a square. [This part was taken with some modification from textbook Fluid Mechanics: Fundamentals and Applications; Yunus A. Cengel and John M. Cimbala; McGraw Hill, 2006.] This experiment is to visualize the laminar, transitional and turbulent flow in a pipe and to determine the boundary of Reynolds number for flow in the pipe. First by controlling the flow rate, establish the laminar flow. Then by slowly increase the flow rate observes what happened to the dye streak. Record the flow pattern change and its volumetric flow rate reading. Determine the boundary of Reynolds number for laminar, transitional and turbulent regime. EQUIPMENT: Hydraulic Bench Reynolds Experiment Apparatus

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QUESTIONS 1. Describe what is laminar, transition and turbulent flow. Illustrate the flows. 2. What is Reynolds Number? What is the critical Reynolds Number? 3. How we can classify the flow regimes by using Reynolds Number? 4. What is the critical Reynolds Number that Reynolds Osborne obtained from his experiment for circular pipe? 5. By using all answers for the questions above, explain what you should do in the experiments in order to achieve the objectives.

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EXPERIMENT # 4 FLOW RATE MEASUREMENT OBJECTIVES The objectives of the experiment are: 1. To show the measurement of flow rate 2. To show the application of Bernoulli equation in flow rate measurement 3. To show effect of minor losses and its modification in flow rate measurement 4. To demonstrate piezometer as a method to measure pressure LEARNING OUTCOMES It is expected by completing the experiment, the students will be able: 1. To determine flow rate by using orifice meter, Venturi meter and rotameter 2. To explain how to calculate ideal flow rate by using Bernoulli equation 3. To determine the correction factor for by using an elbow and a sudden expansion 4. To measure pressure by using piezometer THEORY/BACKGROUND {More in reference book [1] section 5-4 and 8-8} There are various ways of measuring volumetric flow rate. Some flow meters measure the flow rate directly by discharging and recharging a measuring chamber of known volume continuously and keeping track of the number of discharges per unit time. However, most flow meters measure the flow rate indirectly – they measure the average velocity V or a quantity related to average velocity such as pressure and drag, and determine volume flow rate, Q from Q = AV, where A is cross sectional area of flow. Obstruction Flow Meters: Venturi Meter and Orifice Meter One way to measure flow rate is to put obstruction in a pipe flow such as a throat (Venturi Meter) and simple obstruction that reduced the cross sectional area (Orifice Meter). Theoretical ideas behind these flow meters are the conservation of mass and the Bernoulli equation. From conservation of mass we know that reduce of cross sectional area will contribute to an increase of velocity. Thus, from Bernoulli equation, this will lead to a decrease of static pressure. These kinds of flow meters did not measure the flow rate or velocity directly but it measures the drop of static pressure. Then the velocity can be calculated from Bernoulli equation and conservation of mass. The same idea can be applied for sudden expansion and elbow meter.

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Rotameter Rotameter is also known as variable-area flow meter or float meter. A rotameter consists of a vertical tapered conical transparent tube made of glass or plastic with a float inside that is free to move. As fluid flows through tapered tube, the float rises within the tube to a location where the float weight, drag force and buoyancy force are balance each other and the net force acting on the float is zero. The flow rate is determined by simply matching the position of the float against the graduated flow scale outside the tapered transparent tube. Coefficient of Discharge For rotameter the flow rate can be read directly from scale at tapered tube. However, for obstruction flow meter, we need to consider a loss due to viscous (frictional) effects. As we know the Bernoulli equation did not include the viscous effects. The for, any calculation that calculated from the conservation of mass and Bernoulli equation is an ideal volumetric flow rate, not an actual one. Thus, to determine an actual volumetric flow rate a correction factor need to be introduced to the ideal flow rate equation. This correction factor is called as coefficient of discharge. The coefficient of discharge can be defined as the ratio of actual flow rate to the ideal flow rate. Loss coefficient Due to viscous effects, there are losses at the obstruction. The losses at the obstruction can be considered as minor losses. If the pressure drop and average velocity is known, then the loss coefficient can be determined since the pressure drop is proportional to velocity. This experiment is to demonstrate flow rate measurements. For every reading for orifice meter, Venturi meter, elbow and sudden expansion read the reading of rotameter. For Orifice meter, Venturi meter, sudden expansion and sudden contraction: 1. Measure pressure drop (in term of head) as a function of valve opening. 2. Determine theoretical flow rate and actual flow rate. 3. Determine Reynolds number 4. Determine coefficient of discharge 5. Prepare the following graph a. On the same set of axes, plot actual volume flow rate vs. pressure head drop and theoretical flow rate vs. pressure head drop with flow rate on the vertical axis for obstruction flow meter b. Plot actual volumetric flow rate vs. ideal flow rate for rotameter For 90° elbow: 1. Determine the loss coefficient by plotting graph pressure head drop vs. V2/2g (where V is average velocity and g is gravitational acceleration) ** Refer Appendix B for specification of Venturi, Orifice, Elbow, sudden expansion and sudden contraction

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EQUIPMENT: Hydraulic Bench Flow Meter Apparatus QUESTIONS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

What is the principle behind the obstruction flow meter? How to measure theoretical flow rate from obstruction flow meter? Derive theoretical flow rate equation for obstruction flow meter. Explain what is the coefficient of discharge, Cd? How we can calculate the coefficient of discharge experimentally? Explain what the function of piezometer is and how to use it. Illustrate the piezometer. What is loss coefficient? How to determine loss coefficient for sudden enlargement and 90 elbow experimentally? Explain how rotameter works. By using all answers for the questions above, explain what you should do in the experiments in order to achieve the objectives.

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EXPERIMENT #5 FAN TEST

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QUESTIONS 1. Describe and illustrate Pitot-static tube. 2. Explain how to determine volumetric flow rate by using Pitot-static tube. 3. What is velocity profile? 4. Describe and illustrate velocity profile of fully developed laminar flow and fully developed turbulent flow in a circular cross-section pipe.

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Appendix A: Reports Title Page

FINAL LABORATORY REPORT BIOTECHNOLOGY ENGINEERING LAB II (BTE 222) SECTION 1

EXPERIMENT #1 FRICTION LOSSES

EXPERIMENTERS 1. SYED NOH SYED ABU BAKAR, 044856 2. SYED MOHD KHAIRUDIN SYED ALI, 033426 3. MOHD NOOR ZAINAL ABIDIN, 023442 DATE OF EXPERIMENTS Friday, 15th December 2006 (8:30 a.m. to 11:30 p.m.) DATE OF SUBMISSION Friday, 22nd December 2006

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Appendix B: Specification for Flow Meter Apparatus

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Appendix C: Formula to Calculate Cross Sectional Area, Hydraulic Diameter and Height from Datum Line for Rectangular Throat Appendix C: Specification for Friction Losses Apparatus

4

s

1

A

2

3

5

4

3

L

A

h

2 1

x

z

A’

Datum line 15 mm

A3

H g

A’

 hH   A( x)   H    x w  L   

 hH   2w H   x   L    DH ( x)   hH   w  H    x  L   

Cross-section area variation for fluid flow beneath the piezometer tube

Hydraulic diameter variation for the cross-section area for fluid flow beneath the piezometer tube

w

z ( x)  8.5(10 3 ) 

3 x 70

Height from the datum to the center of the cross-section of flow variation (will be explained)

Biotechnology Engineering Lab II Manual 43

Biotechnology Engineering Lab II Manual 44

KULLIYYAH OF ENGINEERING REPORT ASSESSMENT RUBRIC Course Code & Title:

Semester: 1 2014/2015

Instructor: Demonstrator:

Name of Experiment: Roles

Student Name

Matric

Leader: Secretary: Time Keeper: Reporter: Items

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