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FINITE VOLUME ANALYSIS OF CONVECTIVE HEAT TRANSFER AUGMENTATION FROM HORIZONTAL RECTANGULAR FIN BY ELLIPTICAL PERFORATIONS R.B.Gurav J.D.Patil Assistant Professor Army Insitute of Technology Pune, Maharashtra, India Assistant Professor Army Insitute of Technology Pune, Maharashtra, India S.M.Gaikwad Pritee Purohit A.A.Ramgude Assistant Professor Army Insitute of Technology Pune, Maharashtra, India Assistant Professor Army Insitute of Technology Pune, Maharashtra, India Assistant Professor Army Insitute of Technology Pune, Maharashtra, India Abstract: This study examines heat transfer augmentation from a horizontal rectangular fin embedded with elliptical perforation under natural convection compared to the equivalent solid (none perforated) fin using finite volume method. The parameters considered were geometrical dimensions and thermal properties of the fin and that of the perforations. This study shows that the heat dissipation from the perforated fin results in improved heat transfer over the equivalent solid fin. The heat transfer augmentation of perforated fin increases as fin thermal conductivity increases. Key Word: FVA,Fin, elliptical Perforations. I Introduction: The extended surfaces(fins) are frequently used in heat exchanging devices for the purpose of increasing the heat transfer between a primary surface and the surrounding fluid. E.A.M.Elshafei[1] performed the experiment on natural convection heat transfer from circular pin fin heat sinks subject to the influence of its geometry, heat flux and orientation. The geometric dependence of heat dissipation from heat sinks of widely spaced solid and hollow/perforated circular pin fins with staggered combination, fitted into a heated base of fixed area is discussed. They concluded that the heat transfer performance for heat sinks with hollow/perforated pin fins was better than that of solid fins. Wadah Hussein Abdul Razzaq Al-Doori[2] An experimental study was conducted to investigate the enhancement of natural convection heat transfer from the rectangular fins by circular perforations. They showed that the heat transfer rate and the coefficient of heat transfer increases with increased number of perforations. Abdullah H. AlEssa, Ayman M.Maqableh and Shatha Ammourah[3] they showed that ,for a certain range of rectangular dimension and space between perforations ,there is an augmentation in heat dissipation and a reduction in weight over that of the equivalent solid one. Also the heat transfer enhancement of the perforated fin increases as the fin thickness and thermal conductivity increase. M.R.Shaeri, M.Yaghoubi, K.Jafarpur[4] Fluid flow and conjugate conduction-convective heat transfer from a three-dimensional array of rectangular perforated fins with square windows that are arranged in lateral surface of fins are studied numerically.Results show that perforated fins have higher total heat transfer and considerable weight reduction in comparison with solid fins. Bayram Sahin, Alparslan Demir[5] paper reports on heat transfer enhancement and the corresponding pressure drop over a flat surface equipped with square cross-sectional perforated pin fins in a rectangular channel. Abdullah H. AlEssa[6] Heat transfer dissipation from a horizontal rectangular fin embedded with equilateral triangular perforations is compared numerically using one-dimensional finite element technique.The heat dissipation of the perforated fin is computed and compared with that of the solid one of the same dimensions and same thermal properties. The comparison refers to acceptable results and heat dissipation enhancement due to certain perforations. M.R.Shaeri, M.Yaghoubi[7] Three dimensional incompressible laminar fluid flow and heat transfer of a heated array of rectangular perforated and solid fins attached on a flat surface are studied numerically. Thermal performances and effectiveness as well as friction coefficient of perforated and solid fins are determined and compared. A.T.Pise, U.V.Awasarmol[8]Experimental studies were conducted to analyze the natural convection heat transfer using solid & perforated fins for engine cylinder. II Physical Geometry and meshing A Physical Geometry of simple fin B Physical Geometry of fin with elliptical perforation C Meshing of simple fin D Meshing of fin with elliptical perforation Figure1 Physical geometry and meshing of simple fin and fin with elliptical protrusion III Computational methodology The governing equations are the continuity, momentum, and energy equations. The flow is studied under the following assumptions: steadystate, constant fluid properties and no natural convection and body forces. The governing equations for steady mixed convection flow using conservation of mass, momentum and energy can be written as, (1) (2) locations. The convergence criterion is that the residual variations of the mass, momentum and energy conservation equations become less than 10-5.The numerical model is validated by solving the velocity and temperature fields in dimple plate with smooth surfaces, constant inlet velocity and equal wall temperatures. A. Boundary Condition at Inlet Velocity of air =0.001 m/s Static air Temperature =20oC Pressure =105 Pa (3) B At all walls (4) Since the Velocity Component, u and v both are zero at the walls for no-slip conditions, the walls are considered as adiabatic. The computational package, ANSYS Fluent, has been used for the numerical model. It is a 3D solver of the Reynolds Averaged Navier Stokes equations based on the finite volume formulation. Triagonal cells are used to discretize the problem domain with a structured mesh. Grid points are distributed in a non-uniform manner with a higher concentration near the walls due to higher variable gradients expected in these C. At the plate surface Since the velocity component, u and v both are zero at the walls for no-slip conditions. The object is assumed to be isothermally heated. D. Boundary Condition at outlet is Opening (Open to atmosphere), Relative pressure =0 Pa IV Result E Temperature Profile of simple fin along x-y plane F Temperature Profile of fin with elliptical perforation along x-y plane(M6) G Temperature Profile of simple fin along x-z plane H Temperature Profile of fin with elliptical perforation along x-z plane J Pressure Profile of fin with elliptical perforation along x-y plane Figure2 Comparison of simple fin and fin with elliptical perforation I Pressure Profile of simple fin along x-y plane From figure 2 E to J it is observed that fins with elliptical perforation gives better heat transfer and flow distribution. rectangular perforations with aspect ratio of two” International Journal of physical sciences, vol.4(10),pp.540-547,2009 V Conclusion [4]M.R.Shaeri, M.Yaghoubi, K.Jafarpur, “Heat transfer analysis of lateral perforated fin heat sinks” Energy 86,pp.2019-2029, 2009 Figure 2 E to J show that fins with elliptical perforation gives better heat transfer and flow distribution. So it is recommended that the fin with elliptical perforation gives better result than the simple fin. The perforation on the fin increase heat transfer effect and decreases the expenditure of the fin material. REFERENCES [1] E.A.M.Elshafei, “ Natural Convection heat transfer from a heat sink with hollow/perforated circular pin fins” Energy,35:2870-2877. [2] Wadah Hussein Abdul Razzaq Al-Doori, “ Enhancement of natural convection heat transfer from the rectangular fins by circular perforations” International journal of Automotive and Mechanical Engineering ,vol.4,pp.428-436,2011 [3] Abdullah H. AlEssa, Ayman M.Maqableh and Shatha Ammourah, “Enhancement of natural convection heat transfer from a fin by [5] Bayram Sahin, Alparslan Demir, “Performance analysis of a heat exchanger having perforated square fins” Applied Thermal Engineering 28 ,pp.621-632,2008 [6] Abdullah H. AlEssa, “One dimensional finite element heat transfer solution of a fin with triangular perforations of bases parallel and towards its base” Appl. Mech. 79,pp.741751,2009 [7] M.R.Shaeri, M.Yaghoubi, “ Thermal enhancement from heat sinks by using perforated fins” Energy conversion and management 50,pp.1264-1270,2009 [8]A.T.Pise, U.V.Awasarmol, “ Investigation of enhancement of natural convection heat transfer from engine cylinder with permeable fins” International journal of Mechanical Engineering and Technology,pp.238-247,2010