Influence of nanofluids on the thermal performance and entropy generation of varied geometry microchannel heat sink

Abstract

A microchannel heat sink (MCHS) is a compact, effective cooling device that meets the heat dissipation requirements of high-power electronic equipment. This paper investigates the impact of utilizing Al2O3/water, MgO/water, and TiO2/water nanofluids in a rectangular MCHS. To ensure an acceptable comparison, the flow rate is kept constant at 2 m/s. The heat sink base is subjected to 90W of steady heat dissipation, which produces the desired performance result. The vol. concentration of nanofluids ranges from 0 to 8%. The study covers a wide range of MCHS geometries; channel height (Hch) and its width (Wch) ranging from 200 to 800 μm and 100–500 μm respectively. The problem is modeled, validated, and analyzed. The use of nanofluids maximizes the heat transfer performance to 24.95% and minimizes thermal resistance and total entropy generation (TEG) to 15.01%, and 19.96% respectively. TEG decreases to 53.15% when Hch increases and the same increases to 198% when Wch increases. Nanofluids at highest vol. concentration as well as increase in Hch and Wch penalize the system maximum by demanding more pumping power (Ω) by 25.58%, 173.36%, and 39% respectively. Al2O3/water and MgO/water nanofluids deliver better performance and are recommended for future applications. Finally, the authors suggest concentration and geometric parameter ranges for optimality of the thermal performance.

Keywords

• Nanofluids
• Heat transfer
• Microchannel
• Entropy generation
• Bejan number
• Pumping power