Thermal Performance Analysis and Optimization of Microjet Cooling of High-Power Light-Emitting Diodes

The present study investigates the thermal and hydraulic performance of the microjet array cooling system for thermal management of a high-power light-emitting diode array. Three-dimensional numerical analyses were performed for steady incompressible turbulent flow and conjugate heat transfer through a finite volume solver. The performances of several microjet array configurations, viz., 1-jet, 4-jet, 9-jet, 13-jet, and 16-jet arrays, were analyzed at two flow rates and top-cavity heights. The design optimization of a 4-jet array cooling system was performed using a multi-objective evolutionary algorithm. For the optimization, two design variables, viz., ratio of the nozzle diameter and height of the top cavity and ratio of the height and length of the top cavity, were selected. The thermal resistance and pressure drop were selected as the objective functions of the design. The Pareto-optimal solutions were obtained and discussed in view of the thermal resistance and pressure drop and sensitivity of design variables to objective functions.