THERMAL MANAGEMENT OF MICROELECTRONICS USING MICROCHANNEL HEAT SINK WITH INCLINED GEOMETRY AND CNT-BASED NANOFLUID

In the present study, the performance of an inclined microchannel-incorporated heat sink (MCHS) attached to a heat source, mimicking a microelectronic device, has been investigated through computational approach. Three different coolants are used: DI water and aqueous nanofluids of copper oxide (CuO) and carbon nanotube (CNT), respectively. The microchannel of dimension 10 mm × 180 μm × 57 μm is designed with a preset inclination (0°, 0.33°, 0.66°, and 1°). At first, the overall thermal behavior of the MCHS with water as coolant, flowing through the heated microchannel, is evaluated based on the local temperature distribution, local heat transfer coefficient (HTC), and pumping power to assign the performance index for optimization of a specific inclination. In the subsequent part, the optimized geometry is rendered more efficient with nanofluids and modified flow parameters. It is observed that Nusselt number increases by 2.4% for mere 1° inclination as compared to a straight microchannel with water as a coolant and further increases by 2.3% with water + CNT. The efficiency index (<i>h</i>), a parameter governed by flow and thermal resistance, is shown to be highest for 1° inclination with water + CNT as coolant for inlet temperature of 298 K and velocity of 1.312 m/s. The primary reason for efficient cooling with inclination and high velocity is induced pumping arising from gravitational drainage and better thermal transport at channel wall due to proximity between channel wall and base. Physically, this additional cooling can get augmented due to uniaxial elongation like flow of CNT-based nanofluid due to its high aspect ratio.