ANSYS REPORT.pdf

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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..

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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

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3. MATHEMATICAL MODELLING

3.1 DIMENSIONS

3.1.1 SHELL

Dia=7cm

Length=56cm

3.1.2 TUBE

Dia=2.5cm

Length=114cm

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 C

p

(T

H1

–T

H2

)

𝑚̇ = ρ Av

Figure 3.2

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For hot water:

𝑚̇

h

= 0.19625kg/s, C

p

=4180

For cold water:

𝑚̇

c

= 0.573kg/s, C

p

=4180

So by putting the values of area in the above equation we get:

Q̇ = 0.19625 (T

H1

–T

H2

)

Inside TUBE

Q̇ = 0.573 (T

C2

–T

C1

)

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.

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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

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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

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5.4.2 MODEL

In models the energy equation

Is turned on and since radiation

effects are ignored so it is turned off.

5.4.3 MATERIALS

The tubes are made up of steel.

While the fluid is water.The properties are shown in fig

Figure 5.5

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6. BOUNDARY CONDITION

6.1 INLET ZONE

Figure 6.1

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Figure 6.3

Figure 6.4

6.2 HEAT TRANSFER TABLE

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Figure 7.1

6.3 SOLID WALL

Figure 6.6

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7.1 RESULTS

7.2 FLUX REPORT

Figure 7.3

8. CONTOURS

8.1 CONTOURS OF VELOCITY

Figure 7.2

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Figure 8.1

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8.2 CONTOURS OF TEMPERATURE

Figure 8.3

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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 %

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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

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ANSYS REPORT.pdf

Table of Contents

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

3. MATHEMATICAL MODELLING

3.1 DIMENSIONS

3.1.1 SHELL

Dia=7cm

Length=56cm

3.1.2 TUBE

Dia=2.5cm

Length=114cm

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 C

(T

–T

)

𝑚̇ = ρ Av

Figure 3.2

For hot water:

𝑚̇

= 0.19625kg/s, C

=4180

For cold water:

𝑚̇

= 0.573kg/s, C

=4180

So by putting the values of area in the above equation we get:

Q̇ = 0.19625 (T

–T