Computational Study and Optimization of Laminar Heat Transfer and Pressure Loss of Double Layer Microchannels for Chip Liquid Cooling

Abstract

The problem involved in the increase of the chip output power of highperformance integrated electronic devices is the failure of reliability because of excessive thermal loads. This requires advanced cooling methods to be incorporated to manage the increase of the dissipated heat. The traditional aircooling can not meet the requirements of cooling heat fluxes as high as 100 W/cm2, or even higher, and the traditional liquid cooling is not sufficient either in cooling very high heat fluxes although the pressure drop is small. Therefore, a new generation of liquid cooling technology becomes necessary. Various microchannels are widely used to cool the electronic chips by a gas or liquid removing the heat, but these microchannels are often designed to be singlelayer channels with high pressure drop. In this paper, the laminar heat transfer and pressure loss of a kind of doublelayer microchannel have been investigated numerically. The layouts of parallelflow and counterflow for inlet/outlet flow directions are designed and then several sets of inlet flow rates are considered. The simulations show that such a doublelayer microchannel can not only reduce the pressure drop effectively but also exhibits better thermal characteristics. Due to the negative heat flux effect, the parallelflow layout is found to be better for heat dissipation when the flow rate is limited to a low value while the counterflow layout is better when a high flow rate can be provided. In addition, the thermal performance of the singlelayer microchannel is between those of parallelflow layout and counterflow layout of the doublelayer microchannel at low flow rates. At last, the optimizations of geometry parameters of doublelayer microchannel are carried out through changing the height of the upperbranch and lowerbranch channels to investigate the influence on the thermal performance.