Heat Transfer Optimization Studies of Semi-Spherical Protrusions on a Concave Surface during Jet Impingement

Abstract

Much of the literature available on heat transfer enhancement from rough surfaces concerns flat plates or channels. Studies on protruding concave surfaces are surprisingly rare though they have the potential to enhance heat transfer. Therefore, three-dimensional steady-state simulations and corresponding experimental validation is carried out for an air jet impinging on a concave surface projected with semi-spherical protrusions. By providing multiple protrusions, various geometrical configurations are studied by considering the dimensions, angular positions, and pitch between the protrusions. Each individual configuration has its own unique flow pattern which makes prediction of heat transfer complex. This motivates present study to consider entire geometrical parameters affecting heat transfer characteristics with the help of networking tool. Past investigations on protruded flat surfaces concerns random allocation of protrusions. Hence artificial neural network is employed in this study to easily predict the corresponding heat transfer value with set of few input data. Simulation results give detailed flow physics which helps in understanding the heat transfer behavior. It is observed that each protrusion is marked with high-pressure region around its uphill and negative pressure around the downhill. As the flow moves downstream, the protrusions obstruct the flow path and flow separates away as soon as it reaches center of the protrusion. A maximum heat transfer enhancement of 11% is obtained over a corresponding smooth surface.

Acknowledgment

The authors would like to acknowledge late Prof. B.V.S.S.S. Prasad from Department of Mechanical Engineering, Indian Institute of Technology Madras for his constant guidance, motivation, and support throughout this research work. Hence, the authors wish to dedicate this piece of work as a tribute to him.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Alankrita Singh

Alankrita Singh is an Assistant Professor in the Department of Mechanical and Industrial Engineering at IIT Roorkee, since 2022. Prior to this role, she had worked as a Research Scientist in GE Global Research Center. She finished her doctorate from Department of Mechanical Engineering, IIT Madras in 2020. Her research interests include CFD in turbomachines, optimization in heat transfer, thermal management, experimental fluid mechanics area such as Mie-scattering imaging and anemometry.

Chakravarthy Balaji

Chakravarthy Balaji is a Professor in the Department of Mechanical Engineering at IIT Madras. He graduated in mechanical engineering from Guindy Engineering College, Chennai (1990) and obtained his M.Tech. (1992) and Ph.D. (1995) both from IIT Madras. His research interests include computational and experimental heat transfer, optimization in thermal sciences, inverse heat transfer, satellite meteorology, and numerical weather prediction. He has around 200 journal publications to his credit and is an elected fellow of the Indian National Academy of Engineering.