3D MHD lead–lithium liquid metal flow analysis and experiments in a Test-Section of multiple rectangular bends at moderate to high Hartmann numbers

Abstract

Experiments with liquid lead–lithium (Pb–Li) were carried out in a stainless steel (SS) Test Section (TS) consisting of multiple 90° bends for various flow rates and applied magnetic fields of up to 4T. Characteristic MHD flow parameter Hartmann number, Ha (=B0aσ/μ, Ha2 is the ratio of electromagnetic force to viscous force) and interaction parameter, N (=σaB02/ρU,N is the ratio of electromagnetic force to inertial force) of these experiments were varied from Ha=515 to 2060 and N=25 to 270 by changing the applied magnetic field and flow rates respectively. Three dimensional numerical simulations have been carried out using MHD module of FLUENT code. The measured Hartmann and side wall electric potential distribution at various locations of the Test Section have been compared with the numerical simulation results for different Hartmann numbers and interaction parameters (Ha=1030, N=25, 40, 67 for B=2T and Ha=2060, N=129, 161, 270 for B=4T). The numerical predictions based on laminar flow model are matching well with the measured values at all locations including bend regions for high magnetic field and low flow rates. However, at higher flow rates and lower magnetic fields (smaller Ha/Re values), the agreement was not good near the bend regions. This may be attributed to the significant presence of turbulence that was not accounted in the present simulation. The core velocity, estimated from the measured Hartmann wall potential at the locations far away from the bends, matched well with the numerical results. The analysis indicates that the flow distribution becomes rapidly symmetric when it turns at the bend where both the legs are perpendicular to the applied magnetic field. In contrast, flow distribution remains asymmetric for a longer distance when it turns from parallel to perpendicular direction of the applied field. The code is predicting reasonably well for MHD parameters relevant to Blanket Modules for single channel flows with bends.