Numerical investigation on the MHD flow characteristics of eutectic lead-lithium alloy in a U-turn duct with different aspect ratios of the connecting channel

Abstract

Abstract In the design and development of liquid breeder blankets, a number of duct geometries are considered, such as the multiple channel, U-turn duct and T-shaped duct. In the presence of the magnetic field, the motion of electrically-conducting liquid metal leads to Megnetohydrodynamic phenomena, as results of the liquid metal flow profile changes inside the flow channels and additional pressure drop of liquid breeder blankets. A three-dimensional liquid-metal (LM) magnetohydrodynamic (MHD) flows in a U-turn duct with large aspect ratio of the duct cross-section of the connecting channel and in a U-turn conduit with manifold in the connecting region is studied, respectively. Here, the effects of the electrical conductivity of the separating wall in the manifold and different Hartmann numbers on the flow features are considered. Since the 3-D currents are induced due to the complicated geometrical flow path, the electrical conductivity of the separating wall plays a key role in the distribution of mass flow rate among the parallel ducts in manifold. Thus, in the present study, the distribution of the mass flow rate is analyzed for different electrical conductivity of the structural walls. Furthermore, since the aim of the optimal design of liquid-metal blanket is to achieve a proper velocity distribution and reduce the pressure drop caused by the flow opposing Lorentz force, the investigation of the effect of the duct geometry on the pressure distribution in this study is significant.