Numerical Investigation of Enhancement of Heat Transfer Using CNT-Based Nanofluid for Multi-processor Microelectronics

The present work investigates use of Water and Water-based nanofluid as coolant intended to utilize them for cooling a microelectronic system with multiple processors, aka multi-chip module (MCM). The said system is not uncommon and can pose significant issues in thermal management as the thermal design is often complicated by their dense packing. Hence, in this work a microchannel heat sink (MCHS) is designed of dimensions 40 mm × 30 mm × 3 mm to be used as the cooling system of three superheated substrates operating at various heat fluxes ranging from 20 to 50 W/cm2, mimicking high performance microprocessor chips. The overall MCM is engraved at the back of MCHS and a novel design of microchannel, encompassing the heated area while minimizing the total length of microchannel, is proposed. Three coolants are tested—Water, Water + Al2O3 (Alumina) and Water + CNT (Carbon Nanotube), all at volume fraction of 3%. The maximum reduction in temperature of the chips is achieved by Water + CNT, which is 26 °C lower than Water and 20 °C more than Al2O3 for flow rate of 1 m/s and heat flux of 50 W/cm2. Similarly, the overall HTC in Water + CNT is 39 and 28% greater than Water and Water + Al2O3, respectively in the same condition. The elongational flow of high aspect ratio CNT (in water) significantly affects the thermal conductivity of water which in turn enhances the heat transfer from solid wall to coolant.