Performance Evaluation of Vortex Generator of Finite Thickness to Augment Heat Transfer in a Compact Heat Exchanger

Bhupender Sharma, Dr. Gulshan Sachdeva, Dr. Gian Bhushan


The effect of non dimensional thickness of a winglet type vortex generator is investigated in terms of heat transfer rate, stream-wise vortices and flow losses in a plate fin heat exchanger with triangular inserts as secondary fins. The winglet type vortex generators are mounted alternatively on the upper and lower plates of the heat exchanger to disrupt the flow in the triangular domain formed by the inserts. The fluid flow within the duct is considered to be confined and laminar. While the hydrodynamic flow is fully developed, the thermal characteristics are assumed to be in developing stage under isothermal boundary conditions. The winglet is located in the duct where the flow is fully developed (Xi = 2.765 w.r.t. leading edge) at an angle of 27o with respect to the bulk flow direction. The aforesaid performance characteristics are computed numerically by solving the mass continuity, momentum and energy equations. Computational results clearly show an enhancement of 12.91% in the heat transfer rate (quantified as Num/ Nuo) for an increase in non dimensional thickness c/2H from 0.00 to 0.05. Besides, the pressure drop penalty is found to be only 3.8% at Re = 150. The results have also been substantiated by carrying out experiments on a scaled model configuration. Three dimensional velocity components are verified behind the winglet to ensure the stable flow field for non dimensional thickness of winglet c/2H=0.05 and Reynolds number of 350.

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