Multi-Objective Optimization of micro pin-fin arrays for cooling of high heat flux electionics

Sohail R. Reddy, George S. Dulikravich (Florida International University)

CHALLENGE - The thermal management capability of various candidates of micro-pin fin arrays is investigated in this study. The optimum shape for each of the three micro-pin fin geometries is optimized to handle a uniform heat flux of 500 W cm-2, while keeping the maximum temperature below 85°C.

SOLUTION - A fully three-dimensional, steady state conjugate heat transfer analysis was performed on each cooling configuration and a constrained multi-objective optimization was carried out to find pin fin designs configurations capable of cooling high heat fluxes. ANSYS and modeFRONTIER were coupled in the optimization process. The two simultaneous objectives of the study were to minimize maximum temperature and pressure drop (pumping power), while keeping the maximum temperature below 85°C. Stress deformation analysis incorporating the hydrodynamic and thermal loads was performed on each of the three optimized configurations. 

BENEFITS -  The optimization was efficiently performed by coupling response surfaces with the NSGA-II algorithm. The maximum displacement was found to be on the nano-level and the maximum Von-Mises stress for the three configurations was in the range of 47 to 75 MPa. This is significantly lower than the yield strength for silicon of 7000 MPa, indicating the structural integrity of the three optimum configurations.