Liquid cooling technology is necessary to meet the ever-increasing thermal challenges in the field of microelectronics cooling. In liquid-cooling systems, flow through microchannel heat sinks provide high performance and compact cooling, but have a high pressure drop penalty. To address this issue, multi-layered/stacked microchannels have been proposed in the literature. Further, increase in cooling performance of multi-layered microchannels can be achieved using coolants such as nanofluids, having high thermal properties.
In the present study, a finite-volume numerical code with SIMPLE algorithm was used to solve the flow and energy equations, to analyze the thermal performance of a two-layered microchannel with pure water as well as CuO-water nanofluid. Flow rates between from 50ml/min and 320ml/min were considered to study the effect of varying
ow rate on the thermal performance. Also, different volume fractions of nanoparticles are considered to investigate their effect on the thermal performance. The results show that nanofluids enhance the thermal performance, but the increase is not substantial.
Also, the effect of channel geometry on the thermal performance of the two-layered microchannel heat sink has been investigated at two constraints, namely, fixed flow rate and fixed pumping power. The results show that the channel height, channel width and fin width have a significant effect on the thermal performance according to the flow constraints applied. Based on the parametric study, an optimization is carried out to obtain minimal thermal resistance, taking into account realistic constraint of fixed pumping power.
Optimal channel dimensions were found for a range of power values between 0.01W-0.8W, which is the current micropumping power range. The minimal thermal resistance is found to be, is 0:09K/W/cm2 with 4% CuO-water nanouid and at pumping power of 0.8W. The results demonstrate that nanouids do not appreciably enhance the thermal performance of two-layered microchannel heat sink.