Pressure Shock Wave Propagation in Liquid Metals Under the Influence of an External Magnetic Field

Pressure transients in liquid metal systems represent significant safety challenges for magnetic confinement fusion reactors, where electrically conductive breeder materials interact with strong external magnetic fields. Events such as sudden valve closure and pressurised cooling pipe rupture can generate shock waves and severe pressure peaks, potentially exceeding structural limits and compromising component integrity. Under magnetohydrodynamic (MHD) conditions, electromagnetic forces modify fluid motion and influence the propagation of pressure waves, making accurate numerical modelling essential for reactor safety assessment. This work presents SLIMEFoam, a new computational fluid dynamics solver developed within the OpenFOAM framework to simulate pressure shock waves in weakly compressible liquid metals under fusion-relevant magnetic field conditions. The solver implements an induction-less formulation of the MHD equations, accounting for the coupled effects of fluid compressibility, electromagnetic damping, and transient pressure dynamics. Verification of the numerical implementation relies on a previously developed and extensively verified magnetohydrodynamic Method of Characteristics (MaMoC), which provides a reference solution for pressure transients in liquid metal piping systems. Preliminary results for a water-hammer event show good agreement between SLIMEFoam simulations and the one-dimensional reference model. Furthermore, the solver provides access to additional flow quantities, including velocity fields and wall shear stresses, enabling a more comprehensive investigation of shock-driven phenomena. Current development activities focus on addressing the sensitivity of three-dimensional simulations to time-step discretisation. Once this issue has been resolved, the solver will undergo further benchmarking against the only available two-dimensional numerical study of MHD water-hammer phenomena identified in the literature. This work establishes a computational framework for investigating magnetohydrodynamic pressure transients in liquid metal systems, with the objective of supporting the design and safety assessment of advanced fusion reactor components.