Effect of micromagnetorotation on the heat transfer of micropolar Hartmann flow

The present work concerns the influence of micromagnetorotation (MMR) on the heat transfer of a Hartmann micropolar flow. Micromagnetorotation refers to the effect of magnetization on micropolar fluids subjected to an external magnetic field. Until now, magnetization was considered to be parallel to the applied magnetic field and therefore its effect on the flow was neglected. This consideration is incorrect for micropolar fluids, since their anisotropy affects the magnetization. Here, the velocity, microrotation, and temperature fields, as well as the Nusselt number, are analytically studied using a new MHD theory for micropolar fluids, which includes a constitutive equation for the magnetization. It was shown that the MMR is a strong braking mechanism affecting both velocity and microrotation. Moreover, MMR is found to reduce heat transfer by suppressing convection. This situation leads to a reduction in temperature of up to 9% and to a decrease in Nusselt number of up to 6.8%. It seems that micromagnetorotation acts similarly to the Lorentz force; both behave like braking mechanisms on the micropolar fluids, while reducing the convective heat transfer. Hence, the important effect of MMR should be considered for optimizing the flow and heat transfer in industrial and bioengineering applications involving micropolar fluids and magnetic fields.

Automated summary

The study discusses the influence of micromagnetorotation (MMR) on the heat transfer of a Hartmann micropolar flow, revealing that MMR acts as a strong braking mechanism that reduces heat transfer and suppresses convective heat transfer.