Numerical Simulation Using Transition SST Model to Analyze Effects of Expanding Manifold Angle and Jet Spacing for Submerged Liquid Jet Impingement

Abstract

Increasing numbers of under-hood sensors and power electronics modules are becoming standard in both commercial and military vehicles. In order to function reliably, these technologies require a dedicated and dynamic cooling system, such as liquid jet impingement. In a jet array, the spent fluid from upstream jets interacts with the downstream jets degrading their performance. In this study, in order to counteract this effect, an expanding manifold, with larger area for flow downstream, was considered to allow the spent fluid from upstream jets to be diverted, reducing degradation of the heat transfer coefficients downstream. A numerical study of liquid jet impingement utilizing water as the working fluid was performed to examine the heat transfer rate in staggered jet arrays compared to inline jet arrays. The simulations performed examined manifold angles between 0 and 10 degrees, jet Reynolds numbers between 5600 and 14000, and pitches of 2.5, 3, 4.5, and 6 nozzle diameters. The simulations revealed details of the complicated interaction between the jets, their fountain regions and their crossflow in increasing the surface heat transfer coefficient and surface temperature homogeneity. The angled manifold systems had greater temperature uniformity and increased heat transfer coefficients compared to systems with constant area manifolds.