Effect of transverse magnetic fields on the flow and heat transfer characteristics of magnetogasdynamic flows in circular tubes

Abstract

To address the issue of the thermal energy control of high-temperature conductive gases in circular tubes, a new method to regulate the flow and heat transfer by utilizing a transverse magnetic field (TMF) to act on magnetogasdynamic (MGD) flows is proposed. Considering the characteristics of the insufficient development of turbulence at the tube inlet, this study investigated the effects of magnetization range, magnetic transition gradients, Reynolds number (9612 ≤ Re ≤ 40050), and Hartmann number (0 ≤ Ha ≤ 740) on MGD flow in a circular tube under the action of a TMF by applying numerical simulations. The results demonstrated that the MGD flow and heat transfer in a circular tube are anisotropic under an applied TMF, and this behavior becomes increasingly evident with increasing Re and Ha. Moreover, the action of an applied TMF suppresses the overall heat transfer at the tube wall, but the effect exhibits saturation with increasing Ha. In addition, the above suppression effect increases with increasing Re, but the required value of Ha also increases with increasing Re. Finally, within regions that include a magnetic field gradient, symmetric high-speed zones appear near the Roberts boundary layer, and the heat transfer intersity is enhanced in these regions. This enhancement is positively correlated with the magnitude of the magnetic field gradient. The analysis presented herein provides a new and comprehensive means for utilizing magnetic fields to control the thermal energy of MGD flows in circular tubes.