ANSYS REPORT.pdf

Table of Contents ABSTRACT .................................................................................................................................... 2

1.

2.PROJECT DESIGN ............................................................................................................................. 3 DESIGN ...................................................................................................................................... 3

2.1 2.2

PRINCIPLE ............................................................................................................................ 3

2.3

ASSUMPTION ....................................................................................................................... 3

2.4

3-D DESIGN ........................................................................................................................... 3

MATHEMATICAL MODELLING ............................................................................................... 4

3.

DIMENSIONS ........................................................................................................................ 4

3.1 3.1.1

SHELL ............................................................................................................................... 4

3.1.2

TUBE .................................................................................................................................. 4

4.

HEAT TRANSFER THROUH CONVECTION ............................................................................ 4

5.

ANSYS ........................................................................................................................................... 5 PRO-E MODEL .......................................................................................................................... 5

5.1 5.2

MESHING .............................................................................................................................. 6

5.3

MESH REPORT ..................................................................................................................... 6

5.4

SETUP .................................................................................................................................... 7

5.4.1

GENERAL ......................................................................................................................... 7

5.4.2

MODEL ............................................................................................................................. 8

5.4.3

MATERIALS .................................................................................................................... 8

BOUNDARY CONDITION ........................................................................................................... 9

6.

INLET ZONE ............................................................................................................................. 9

6.1 6.2

HEAT TRANSFER TABLE ................................................................................................. 10

6.3

SOLID WALL ...................................................................................................................... 11

CALCULATIONS ........................................................................................................................ 11

7. 7.1

RESULTS ................................................................................................................................. 12

7.2

FLUX REPORT ........................................................................................................................ 12 CONTOURS ................................................................................................................................. 12

8.

CONTOURS OF VELOCITY .................................................................................................. 12

8.1 8.2 9. 10.

CONTOURS OF TEMPERATURE ..................................................................................... 14

CONCLUSION: ............................................................................................................................ 15 REFERENCES ......................................................................................................................... 16

1. ABSTRACT In this report, we are going to discuss the thermal analysis using simulation software (ANSYS©, Fluent) and counter current flow. We are using water as working fluid. We have used “Pro-e” for the preparation of the geometry. Workbench for meshing of the geometry of our proposed project. For simulation and determination of required heat transfer rate, we have used "ANSYS©, Fluent”.We have come to know that for constant Heat Transfer Rate the size of heat exchanger is compact for two tube passes than one tube passe due increases in larger surface area..

2.PROJECT DESIGN 2.1 DESIGN The design consists of a simple heat exchanger with one shell and two tube passes and different materials..Hot water will flow through inside tube while cold water is flowing through annular tube.

2.2 PRINCIPLE Heat transfer is the exchange of thermal energy between physical systems. The rate of heat transfer is dependent on the temperatures of the systems and the properties of the intervening medium through which the heat is transferred. Heat will transfer from the hot water to the cold water, by convection only.

2.3 ASSUMPTION i. Thermal resistance of inner tube is negligible because the tube material is highly conductive and its thickness is negligible. ii. Flow is fully developed. iii. Radiations effects are neglected. iv. Properties of water are constant. v. Steady operating condition exist. vi. Heat Exchanger is well insulated so that heat loss to the surrounding is negligible and thus heat transfer from cold fluid is equal to the heat transfer to the cold fluid.

2.4 3-D DESIGN

Figure 3.1

3. MATHEMATICAL MODELLING 3.1 DIMENSIONS 3.1.1 SHELL Dia=7cm Length=56cm

Figure 3.2 3.1.2

TUBE

Dia=2.5cm Length=114cm

Figure 3.3

4. HEAT TRANSFER THROUH CONVECTION The LMTD method could still be used for this alternative problem, but the procedure would require tedious iterations, and thus it is not practical. In an attempt to eliminate the iterations from the solution of such problems, Kays and London came up with a method in 1955 called the effectiveness–NTU method, which greatly simplified heat exchanger analysis. This method is based on a dimensionless parameter called the heat transfer effectiveness ϵ defined as

For heat transfer through convection we have: Q̇= ṁ Cp (TH1 –TH2) 𝑚̇ = ρ Av

For hot water: 𝑚̇h = 0.19625kg/s, Cp =4180 For cold water: 𝑚̇c = 0.573kg/s, Cp =4180 So by putting the values of area in the above equation we get: Q̇ = 0.19625 (TH1 –TH2) Q̇ = 0.573 (TC2 –TC1)

Inside TUBE Anular TUBE

Now by simply putting the values of temperature gradient we can calculate the heat transfer through every tube. From the above calculations we can see that heat transfer through each tube is equal.

5. ANSYS 5.1 PRO-E MODEL The model is made on the PRO-E software in 3-D. When model is made then it will easily import in ANSYS for further Analysis.

Figure 5.1

5.2

MESHING

After naming the different zones and choosing the appropriate , Meshing type, sizing and the type of centre, following mesh was generated.

Figure 5.2

5.3 MESH REPORT

Table 5.1

Table 5.2

5.4 SETUP 5.4.1

GENERAL

The generals for this tube are Selected as shown in figure With the maximum aspect ratio Equal to 1.69223e+01

Figure 5.4

5.4.2

MODEL

In models the energy equation Is turned on and since radiation effects are ignored so it is turned off.

Figure 5.5

5.4.3

MATERIALS

The tubes are made up of steel. While the fluid is water.The properties are shown in fig

Figure 5.6

6. BOUNDARY CONDITION 6.1 INLET ZONE

Figure 6.1

Figure 6.2

Figure 6.3

Figure 6.4

6.2 HEAT TRANSFER TABLE

Figure 6.5

6.3 SOLID WALL

Figure 6.6

7. CALCULATIONS

Figure 7.1

7.1 RESULTS

Figure 7.2

7.2 FLUX REPORT

Figure 7.3

8. CONTOURS 8.1 CONTOURS OF VELOCITY

Figure 8.1

Figure 8.2

8.2 CONTOURS OF TEMPERATURE

Figure 8.3

Figure 8.4

Effectivness(experimental): mass flow rate of hot water=.273kg/s mass flow rate of cold water=.196kg/s Cold water inlet temperature:27 ℃ Hot water inlet temperature:62 ℃ Hot water outlet temperature:54℃ Cold water out let temperature:31 ℃

∆T max=Th1-Tc1=35 ℃

,Cmin=0.196 *4180=819

Q’max=cmin ∆T max=819* 35=28674.8 watts Q’=mcp (Th1-Th2)=mcp(Tc2-Tc1)=0.273*4180*(62-54)=9129.12watts Effectiveness= Q’/ Q’max=19161.12/28674.8=31 %

9. CONCLUSION: In our project,we come to know that one shell with multiple passes are compact design .And the heat transfer rate is more in counter flow than in co current flow. The difference between the values calculated and values from simulation since there is a difference between real and ideal cases.

10. REFERENCES 1) HEAT TRANSFER BY YUNUS A. CENGEL 2) https://www.youtube.com/results?search_query=ansys+tutorials+for+simulation 3) https://confluence.cornell.edu/display/SIMULATION/FLUENT+Learning+Modules