Reducing Inter-Chip Temperature Differences in Computers Using Vortex Generators in Forced Convection

Abstract

Experiments were conducted to investigate methods of reducing inter-chip temperature differences in forced convective direct immersion cooling of semiconductor chips using a dielectric liquid (FC-77) as coolant. The experiments were conducted in a closed-loop flow facility with a 5 × 15 array of chips mounted on the bottom wall of a horizontal channel and with vortex generators installed on the opposite wall, upstream of the heated chip. Single, half delta-wing vortex generators of two heights, as well as a pair of counter-rotating vortex generators, were tested at different placement locations with respect to the heated chip. The channel height-based Reynolds number was varied from 1000 to 7500. Heat transfer coefficients and pressure drop measurements were obtained. The taller vortex generator placed 2.5 chip heights upstream of the heated chip was found to yield the best results. The increase in pressure drop due to each of the individual vortex generators was found to be negligible. The greatest enhancement in heat transfer of 17 percent was obtained at Reynolds numbers in the transitional flow regime.