Numerical simulation of liquid metal MHD flows in a conducting rectangular duct with triangular strips

Magnetohydrodynamic (MHD) pressure drop remains a key issue in the application of liquid metal blankets in nuclear fusion reactors. MHD pressure drops and velocity distributions in MHD duct flows are closely related to the shape of the duct cross-section. In this paper, MHD flows in an ordinary electrically conducting rectangular duct (R-duct), and an electrically conducting rectangular duct with triangular strips (RTS-duct) subjected to a uniform magnetic field are investigated numerically using an in-house MHD solver developed in OpenFOAM. The results show that the velocity fluctuation of the MHD flow in the RTS-duct grows, and the dimensionless MHD pressure drop reduces as the direction of the magnetic field is fixed, and the Hartmann number increases. The velocity fluctuation in the RTS-duct spreads more easily when the triangular strips (TS) are on the Hartmann walls instead of the side walls as the magnetic field intensity is the same. Besides, the MHD pressure drop in the RTS-duct is only a little bit higher than that in the R-duct as the TSs are on the Hartmann walls. The MHD pressure drop in the RTS-duct is over 20 % higher than that in the R-duct, and the relative difference increases with the Hartmann number increasing when the TSs are on the side walls. The results about the MHD pressure drop and the flow instability in the RTS-duct can be referenced in the liquid metal blanket design.

Automated summary

The study found that the velocity fluctuation of MHD flow in RTS-duct increases as the magnetic field direction is fixed and the Hartmann number increases, while the dimensionless MHD pressure drop decreases. The velocity fluctuation spreads more easily when TSs are on the Hartmann walls, and the MHD pressure drop in the RTS-duct is only slightly higher than in the R-duct.