Electromagnetic (EMP) pumps move an electrically conductive liquid metal without contact. As a result, they provide an excellent seal for coolant in fast neutron or fusion reactors while minimizing waste inventory. In induction EMPs, the pumping Lorentz force results from the interaction between the exciting magnetic field and the current it induces in the conductive liquid moving at a relative velocity. This coupling is typical of magnetohydrodynamics (MHD).
When MHD flows become turbulent, the scientific challenge is to describe the turbulent boundary layers. Direct numerical simulation (DNS) makes it possible to dispense with sub-mesh models to describe the boundary layers. The trade-off is computational time, which is prohibitive for engineers who want to design a PEM in real geometry. The goal of this work is to calculate MHD quantities (velocity, current, and electric potential) using DNS in a simplified geometry that is sufficiently representative of an EMP. Calculations can be performed in parallel using models with closure laws that are more accessible to the engineer. The goal is to establish domains of validity for these closure laws, if they exist.
An MHD flow in a channel will be modeled, either laminar or slightly turbulent. The magnetic field can be imposed as uniform, non-uniform, sliding and/or oscillating. The numerical simulations will be validated on an experimental device to be completed, which will allow Galinstan flow (metal alloy which is liquid at room temperature) and ultrasonic or electric potential velocimetry.
The aim of this thesis is to gain a better understanding of turbulent MHD flows in channels, to implement into future work on modeling electromagnetic pumps for representative Reynolds and Hartmann numbers. This work opens up career prospects particularly in research centers and R&D departments in industry.