Control volume finite element method for entropy generation minimization in mixed convection of nanofluids

A numerical study is performed to analyze the heat transfer and entropy production for both natural and mixed convection in a rectangular enclosure filled with water-based nanofluids. This article presents a new approach for minimizing the entropy production rate in different flow configurations with nanofluids. The governing equations are discretized with a control-volume-based finite element method (CVFEM). The thermophysical properties of the nanofluids are evaluated based on experimental data. The analysis considers the effects on entropy production due to variations of the volume fraction (0≤Ø≤0.12) of the nanofluid, aspect ratio (AR) of the enclosure, and moving wall velocity (vw). The article compares the entropy production rates and heat transfer rates for three different nanofluids. The results for a natural convection case indicate a reduction in the rate of entropy production as the nanoparticle volume fraction increases. Results for the mixed convection case establish the optimal nanoparticle volume fraction that minimizes the total entropy production. Through this numerical model, the distribution of nanoparticles and cavity aspect ratio can be effectively controlled to minimize the entropy production rates