Fluid flow and heat transfer attributes of an inclined pulsating impinging air jet

Abstract

Jet impingement technology and its underline flow and heat transfer attributes have been studied by researchers over the last few decades. Due to its high heat flux removal capacity over conventional methods, it has found its way into thermal management applications. Any system which rejects excess heat needs to be removed, otherwise, it can affect the performance of the system. For example, overheating the battery pack in an electric vehicle can deteriorate functioning and thermal runaway. Pulsating jet impingement has been proven to be one of the techniques that can improve the heat removal ability from the impingement surface. In pulsating jets, the inlet mass flow rate varies as a function of time. Due to change in velocity, periodic entrainment of surrounding fluid occurs; resulting in a larger mass flow rate when the jet fluid reaches the surface, causing enhanced heat transfer. When a periodic impingement of vortices happens, it breaks the boundary layer, allowing more heat to be removed from the target surface. In the current work, the effect of the jet inclination angle on the flow and heat transfer characteristics is studied. In the case of a steady jet, the inclination angle has altered the flow field drastically, and an optimal angle of ~30° has been identified for a higher heat transfer rate. As the hydrothermal performance of pulsating jet differs largely from the steady jet, the effect of inclination needs to be investigated along with the frequency of the pulsation to arrive at optimum parameters. The transition shear stress transport with the intermittency model will be used to simulate the pulsating jet impingement. First, a validation with experimental data will be obtained to ensure the numerical model is able to capture the flow physics correctly. Thereafter, a grid independence study will be followed by parametric analysis to reach concise information on flow and heat transfer attributes of inclined pulsating jet impingement.