Influence of uniform magnetic field on hydrothermal characteristics and entropy production in a nanofluid filled rectangular grooved channel

Abstract

The implementation of a uniform magnetic field can be beneficial for controlling thermal convective processes in magneto-thermal devices and systems. In research of productive energy employment and superior thermal efficiency, the present numerical research study aimed to investigate the flow structure, thermal behaviors, and entropy production of nanofluids with a mixture of CuO and water in a rectangular grooved channel subjected to the uniform magnetic field in the transverse direction. Convective dynamics in such rectangular grooved channels subjected to a uniform magnetic field have not been comprehensively investigated considering flow structures, thermal performances and entropy characteristics. The impact of different variables namely nanoparticle volume concentrations, Φ Hartmann numbers, Ha and Reynolds numbers, Re on the hydrothermal characteristics is numerically explored. According to acquired outcomes, the uniformly implemented magnetic field in the rectangular grooved channel causes significant variations of flow characteristics demonstrated by the streamline patterns and reduces the extent of the recirculation flow zone in rectangular grooves at Re = 250 and 1250. During the application of the uniform magnetic field, the thermal boundary layer formed in the rectangular grooves becomes thinner, while the temperature gradient in the near regions of the heated walls increases. Numerical simulations show that the average Nusselt number, Nuavg increases by approximately 9.08% for Ha = 8 and 30.42% for Ha = 24 at Re = 250, and by 0.087% for Ha = 8 and 21.13% for Ha = 24 at Re = 1250, compared to the case where no uniform magnetic field is applied, Ha = 0. It can be observed that for a given value of Re, the total entropy reduces sharply for Ha>8, due to the significant effect of high magnetic field intensity over both thermal and flow distributions. The outputs of this study could be very beneficial for designers modeling any device or system including thermal energy transportation in various industrial applications such as cooling circuits of electronic components and fast fission reactors, materials science and metallurgical processes.