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HEAT TRANSFER THROUGRIBBED FINS

UNDER THE GUIDANCE OF

MR. M.K. CHAITANYA M.TECH |ASSISTANT PROFESSOR, DEPT. OF

MALINENI PERUMALLU

EDUCATIONAL SOCIETYS GROUP OF INSTITUTIONS

BY

ANGALURI SRIKANTHMEKALA JOSEPH UDAY KIRA

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Topics To Be Covered

Heat Transfer

Introduction To Fins

Purpose Of Fins

Types Of Fins

Applications

Advantages & Disadvantages

Designing Of Fin Using Catia

Procedure For Ansys Analysis

Analysis Of Designed Fins Using A

Conclusion

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Heat TransferThe transmission of energy from one region to another as a result oftemperature gradient

Importance Of Heat TransferThe study of heat transfer is carried out for the follow purposes:-

i) To estimate the rate of flow of energy as heat through the boundary of a systemstudies (both under steady and transient conditions).ii)To determine the temperature field under steady and transient conditions.

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Introduction To Fins

Fin is a surface that extends from an object to increase the rate of heat transfer tothe environment by increasing convection.

PURPOSE OF FINSThe purpose of fins is to improve heat dissipation from a surface to surroundings.

VARIOUS TYPES OF FINSThe fins are designed and manufactured in many shapes and forms. These aremainly of following types.1. Straight fin2. Annular fin3. Pin fin or spineMaterials used for fins are copper, aluminium and iron.

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APPLICATIONS

The applications of fins1. Automobiles2. Aircrafts3. Air compressors4. Refrigerators5. Generators.

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ADVANTAGES1. Due to the extended surfaces of the fins more amount of heat is

dissipated.2. Cost of manufacturing is less.3. Ease of design.

4. According to the rate of heat transfer type of fins can be selected.5. Less weight and low complications.

DISADVANTAGES1. It occupies more space.2. It cannot be used where high amount of heat is to be dissipated.

DESIGN AND THERMAL ANALYSIS OF FINSThe procedure includes two steps:-

Step 1: Designing of fins using CATIA software andStep 2: Analysis of designed fins using ANSYS software.

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DESIGN

Let us get started by starting up catia and opening a new Part Design file (Start > MDesign > Part Design) and name the part Fins.

Select the xy axisand select the Sketch tool

Use the Line tool to draw the straight lines of the fins according to the dimensisketch of fins according to the picture below:

http://2.bp.blogspot.com/_MMmobCHC9Ow/TEPqRkr6LlI/AAAAAAAAAHM/0rZXR-odmX0/s1600/17.pnghttp://2.bp.blogspot.com/_MMmobCHC9Ow/TEPpydCjDjI/AAAAAAAAAHE/0r0uKUfEOOQ/s1600/3.png

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To remove any unwanted lines during the drawing of sketch use the Quick Trim

which can be found under the Trim tool. You can find the Trimtool in the Operatoolbar.

Select the Quick Trimtool and select the lines that we want to delete.After the completion of sketch exit the workbench. Then the sketch is shown as

http://2.bp.blogspot.com/_MMmobCHC9Ow/TEPtHvvCSOI/AAAAAAAAAI0/IH1XNSx5GEg/s1600/20.pnghttp://4.bp.blogspot.com/_MMmobCHC9Ow/TEPrbNnuKtI/AAAAAAAAAH8/TOj8OHv3_Kg/s1600/22.pnghttp://3.bp.blogspot.com/_MMmobCHC9Ow/TEPrQt9jyLI/AAAAAAAAAH0/PNL_3Sr8DxE/s1600/21.png

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select the Padtool. Set the Lengthto 50mm and select the mirrored extent belowand then click OK. The part will be displayed as shown below.

SAVE the part design in .igs format so that the design of fins is completed.

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ANALYSISLet us start our analysis using finite element analysis method (FEA). It is a technique uto obtain approximate solutions. ANSYS is a software package used for analysis of acomponent by FEA method.

PROCEDURE FOR ANSYS ANALYSISThe procedure for static analysis consists of these main steps:I. Pre-processor phase

1. Discretization of structure.2. Numbering of nodes and elements.

II. Solution phase

1. Selection of displacement function or interpolation function.2. Define the material behavior with stress-strain relations and strain displacemen

relations.3. Derivation of element stiffness matrix and equations.4. Assemble the element equations to get global or total equations.5. Applying boundary conditions.6. Solution for unknowns.

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III. Post-processor phase

1. Computation of element strains and stressesfrom nodal displacements2. Interpret the results.

The following table shows the brief description of the steps followed in each Pha

Pre-Processor Phase Solution Phase Post- Proces

1. Geometric Definition Element matrix formation Post solution o

2. Mesh Generation Overall matrix Triangulation Post Data Print

3. Constraint & load Definition Displacement, stress, etc Post data Scann

4. Model display Post data Scann

5.Material Definition

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A. PRE-PROCESSOR

Pre processor has been developed so that the same program is available on microsuper mini and main frame computer system to other.

Pre processor is an interactive model builder to prepare FE (finite element) model ainput data. The following section describes various capabilities and features of the processor.

B. SOLUTION

The solution phase deals with the solution of the problem according to the problem

definitions. All the tedious work of formulating and assembling of matrices are donethe computer, and finally displacements and stress values are given as output. Somthe capabilities ANSYS are linear static analysis, transient dynamic analysis etc.

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C. POST PROCESSOR

It is a powerful user-friendly post processing program. Using interactive color grapit has extensive plotting features for displaying results obtained from the finite

element analysis.

Employing state of the art image enhancement techniques, facilities viewing of:Contours of stresses, displacements, temperatures etc.,

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ANALYSIS OF DESIGNED FINS USING ANSYS

PREFERENCES

Select THERMAL analysis option from the preferences menu.click OK.

PREPROCESSOR

ELEMENT TYPE

ELEMENT TYPE Add Add solid Tet 10 node 87 click OK click CLOSE.

MATERIAL PROPERTIES

MATERIAL PROPERTIES Thermal conductivity Isotropic Give theconductivity value as 170 click OK click CLOSE.

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GEOMETRIC MODEL

As we have designed the fins using CATIA. let us import the file to ANSYS by follow

Click FILE on UTILITY MENU Import .iges click OK click OK.

The Geometric model will be imported to the working area as shown in the follow

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MESHING

MESHING lines all lines Give element size as 5 ok.

Now the Geometric model will be converted into Finite element model as shown in

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LOADS

LOADS Apply Heat flux select the bottom area Give the Heat flux value ok.

LOADS Apply Heat flux select all the remaining areas Give the film coef40 w/m^2 and bulk temperature as 294k ok.

SOLUTION:

solve current linear solution ok

*solution is done*

click OK close.

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GENERAL POST PROCESSOR

PLOT RESULTS

Plot results Nodal solution DOF ok.

DOF RESULT

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Plot results Nodal solution Thermal flux X component ok.

Thermal flux X component

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Plot results Nodal solution Thermal flux Y component ok.

Thermal flux Y component

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Plot results Nodal solution Thermal flux Z component ok.

Thermal flux Z component

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Plot results Nodal solution Thermal flux vector sum ok.

Thermal flux vector sum

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Plot results Nodal solution Thermal Gradient X component. ok.

Thermal Gradient X component

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Plot results Nodal solution Thermal Gradient Y component ok.

Thermal Gradient Y component

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Plot results Nodal solution Thermal Gradient Z component ok.

Thermal Gradient Z component

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Plot results Nodal solution Thermal Gradient vector sum ok.

Thermal Gradient vector sum

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CONCLUSION

Heat transfer through ribbed fins is designed using Catia V5R18 and analyzed usitotal length of the part is 330 mm in which fins are of different cross-sections are mafrom the above results that fin are subjected to maximum temperatures and minimu

which are as follows:

Index min MaxD.O.F 294 472.66

Thermal flux x-comp -1625 1624

Thermal flux y-comp 0.904E-04 1271

Thermal flux Z-comp -1674 1674

Thermal flux vector sum 0.208E-03 1873

Thermal gradient x-comp -9.552 9.557

Thermal gradient y-comp -7.478 -0.523E-06

Thermal gradient z-comp -9.845 9.845

Thermal gradient vector sum 0.122E

-05

11.015

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Questions?

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