Multi-Objective Optimization of Micro Pin-Fin Arrays for Cooling of High Heat Flux Electronics

Abstract

The thermal management capability of various candidates of micro-pin fin arrays is investigated. An integrated circuit having a footprint of 4 × 3 mm with micro-pin fin array having circular, airfoil and convex cross-section is considered. The three pin fin cross-sections along with the cooling schemes are optimized to handle a uniform heat flux of 500 W/cm2 applied to the top surface of the electronic chip. 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 for each of the three micro-pin fin shapes to find pin fin designs configurations capable of cooling such high heat fluxes. The design variables were the geometric parameters defining each pin fin cross section, height of the chip and inlet speed of the coolant. The two simultaneous objectives were to minimize maximum temperature and pressure drop (pumping power), while keeping the maximum temperature below 85°C. A response surface was constructed for each objective function and was coupled with a genetic algorithm to arrive at a Pareto frontier of the best trade-off solutions. Stress-deformation analysis incorporating the hydrodynamic and thermal loads was performed on each of the three optimized configurations. The maximum displacement was found to be on the nano-level, and the Von-Mises stress for each configuration was found to be significantly below the yield strength of Silicon.

Multi‐objective optimization of a Fibonacci phyllotaxis micro pin‐fin heat sink

“…From the figure, the maximum temperature reduction along the route amounted to 0.1%, displaying a high level of concordance with the earlier outcomes reported by Reddy and Dulikravich. 21 This indicates excellent agreement between the validation model and the preceding research. | 3247…”

“…A heat flux of 500 W/cm 2 was chosen as an appropriate forecast of future heat dissipation requirements. 6,21 A uniform highest heat flux of 500 W/cm 2 is applied on the top surface of the T A B L E 1 Design variables and their levels.…”

“…The proposed heat sink designated has a square shape with dimensions of 3.464 mm × 3.464 mm based on literature. 21,22 Each pin-fin in an array connected to the top and bottom walls of the cooling micro-array device and was the same size and form. Each of the arrays had top, bottom, and sidewalls that were 30 μm thick because of the embedded cooling idea.…”

“…For validation, a physical model has a diameter of 120 µm, a height of 250 µm, and an inlet velocity of coolant with 2.2 m/s were chosen from the previous work of S. R. Reddy et al, 4 and Reddy and Dulikravich. 21…”

“…Considering that typical electronic chips experience heat fluxes around 100 W/cm 2 , a forecasted heat flux of 500 W/cm 2 was deemed suitable for future heat dissipation needs. 6,21 This uniform and maximum heat flux of 500 W/cm 2 is imposed on the top surface of the microchannel, which has a cross-sectional area of 12 mm 2 and is fitted with pin fins. All other surfaces are treated as adiabatic,…”