Inverse Design of Cooling of Electronic Chips Subject to Specified Hot Spot Temperature and Coolant Inlet Temperature

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

CHALLENGE - Most methods for designing electronics cooling schemes do not offer the information on what levels of heat fluxes are maximally possible to achieve with the given material, boundary and operating conditions. The goal was to identify a cooling pin-fin shape and scheme that is able to push the maximum allowable heat flux as high as possible without the maximum temperature exceeding the specified limit for the given material. 

SOLUTION - The three objectives in this study were to minimize maximum temperature and pumping power, while maximizing the background and hotspot heat fluxes. This problem was solved using multi-objective constrained optimization and metamodeling for an array of micro pin-fins with circular, airfoil and symmetric convex cross sections. ANSYS was used for a computational grid created for each of the initial candidate designs, as well as 3-D conjugate heat transfer analysis. Radial Basis Function response surfaces were used in modeFRONTIER to get to a Pareto frontier of best trade-off solutions. The Pareto optimized configuration indicates the maximum physically possible heat fluxes for specified material and constraints.

BENEFITS - Values of the objective functions obtained from the Multiquadric Radial Basis Functions interpolation coupled with NSGA-II in modeFRONTIER differed by less than 2% from those obtained by the full 3-D conjugate heat transfer analysis. The basic conclusion is that much higher average heat fluxes and hot spot heat fluxes can be handled by the optimized arrays of micro pin-fins and the optimized inlet coolant conditions.