Performance analysis and design optimization of micro-jet impingement heat sink

This study evaluated a silicon-based micro-jet impingement heat sink for electronic cooling applications. First, the pressure-drop and thermal characteristics were investigated for steady incompressible and laminar flow by solving three-dimensional Navier-Stokes equations, and the performance enhancement was carried out through parametric and optimization studies. Several parallel and staggered micro-jet configurations consisting of a maximum of 16 jet impingements were tested. The effectiveness of the micro-jet configurations, i.e. inline 2 x 2, 3 x 3 and 4 x 4 jets, and staggered 5-jet and 13-jet arrays with nozzle diameters 50, 76, and 100 mu m, were analyzed at various flow rates for the maximum temperature-rise and pressure-drop characteristics. A design with a staggered 13-jet array showed the best performance among the various configurations investigated in the present study. The design optimization based on three-dimensional numerical analysis, surrogate modeling and a multi-objective evolutionary algorithm were carried out to understand the thermal resistance and pumping power correlation of the micro-jet impingement heat sink. Two design variables, the ratio of height of the channel and nozzle diameter, and the ratio of nozzle diameter and interjet spacing, were chosen for design optimization. The global Pareto-optimal front was achieved for overall thermal resistance and required pumping power of the heat sink. The Pareto-optimal front revealed existing correlation between pumping power and thermal resistance of the heat sink. Of the range of Pareto-optimal designs available, some representative designs were selected and their functional relationships among the objective functions and design variables were examined to understand the Pareto-optimal sensitivity and optimal design space. A minimum of 66 A degrees C of maximum-temperature-rise was obtained for a heat flux of 100 W/cm(2) at a pressure drop of about 24 kPa.