Laboratory model of electrovortex flow with thermal gradients, for liquid metal batteries

TL;DR

This paper introduces a laboratory model to study fluid dynamics in liquid metal batteries, focusing on thermal gradients and electrovortex flow, validated through measurements and scaling relationships.

Contribution

It presents a novel experimental setup that isolates and combines thermal and electrovortex flows in a liquid gallium layer, with detailed diagnostics and validation.

Findings

Scaling relationships match theoretical predictions

Flow measurements agree with previous studies

Setup effectively simulates LMB flow conditions

Abstract

We present a novel laboratory setup for studying the fluid dynamics in liquid metal batteries (LMBs). LMBs are a promising technology suited for grid-scale energy storage, but flows remain a confounding factor in determining their viability. Two important drivers of flow are thermal gradients, caused by internal heating during operation, and electrovortex flow (EVF), induced by diverging current densities. Our setup explores thermal gradients and electrovortex flow separately and in combination in a cylindrical layer of liquid gallium, simulating the behavior in a single layer of an LMB. In this work, we discuss the design principles underlying our choices of materials, thermal control, and current control. We also detail our diagnostic tools - thermocouple measurements for temperature and Ultrasonic Doppler Velocimetry (UDV) probes for velocities - and the design principles which go into choosing their placement on the setup. We also include a discussion of our post-processing tools for quantifying and visualizing the flow. Finally, we validate convection and EVF in our setup: we show that scaling relationships between the nondimensional parameters produced by our data agree well with theory and previous studies.