Thermal performance of nanofluid flow in microchannels

Two effective thermal conductivity models for nanofluids were compared in detail, where the new KKL (Koo–Kleinstreuer–Li) model, based on Brownian motion induced micro-mixing, achieved good agreements with the currently available experimental data sets. Employing the commercial Navier–Stokes solver CFX-10 (Ansys Inc., Canonsburg, PA) and user-supplied pre- and post-processing software, the thermal performance of nanofluid flow in a trapezoidal microchannel was analyzed using pure water as well as a nanofluid, i.e., CuO–water, with volume fractions of 1% and 4% CuO-particles with dp = 28.6 nm. The results show that nanofluids do measurably enhance the thermal performance of microchannel mixture flow with a small increase in pumping power. Specifically, the thermal performance increases with volume fraction; but, the extra pressure drop, or pumping power, will somewhat decrease the beneficial effects. Microchannel heat sinks with nanofluids are expected to be good candidates for the next generation of cooling devices.