A Numerical and Experimental Study of Staggered Submerged Liquid Jet Arrays Using Variable Angle Discharge Manifolds

Increasing numbers of power electronics modules are becoming standard in both commercial and military equipment. 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 a larger area for flow downstream, was used to allow the spent fluid from upstream jets to be diverted, reducing degradation of the heat transfer coefficients downstream. A series of numerical and experimental studies of liquid jet impingement utilizing water as the working fluid were performed to examine the heat transfer rate in staggered jet arrays. The simulations performed examined manifold angles between 0° and 10°, jet Reynolds numbers between 5600 and 14 000, and pitches of 2.5, 3, 4, 4.5, and 6 nozzle diameters. The experimental technique features a unique method of translation in two orthogonal axes to provide experimentally measured 2-D maps of heat transfer coefficient. The simulations, modeled in ANSYS Fluent, revealed details of the complicated interaction between the jets, their fountain regions, and the crossflow. The angled manifold systems had greater temperature uniformity and increased heat transfer coefficients compared to systems with constant area.