Numerical Analysis of Various Nanoparticles Size Effects on Thermal Performance of Nanofluid in A Microchannel Heat Sink

Development of thermal management methods for advanced electronic devices, especially for micro and nano-scales are important issues which directly affects system performance. MicroChannel Heat Sink (MCHS) is one of the efficient technologies improving the thermal performance and some research works have been conducted in this field recently. The aim of the present paper is to investigate the nanoparticles size effects on thermal performance of a trapezoidal MCHS numerically. In the present study, employment of Water - Alumina (〖"Al" 〗_"2""O" _"3" ) and Water – CuO nanofluids is modeled using Eulerian – Eulerian two-phase approach. Solving equations of continuity, momentum and energy in the computational domain is performed via Finite Volume Method (FVM) in FLUENT with the accuracy of 〖10〗^(-6). Also, since in most studies nanofluids are simulated as a homogeneous (single phase) fluid a comparison between the present two-phase models with homogeneous modeling is conducted and it is found that two phase modeling shows 13.8% better performance in comparison with other single phase modeling. The results showed that adding of both nanoparticles increases the heat transfer in microchannel and increasing the diameter of the nanoparticles results in a decrease of heat transfer rate as Alumina and Cu-O nano particles, show 6.63% and 5.022% reduction in heat transfer rate, respetively. Also in the meantime, Alumina nanoparticles have a lower heat transfer coefficient than CuO nanoparticles. Hence, Water - CuO nanofluid is more appropriate for trapezoid geometry and by optimizing the particle size the thermal efficiency of the system can be maximized.