Heat transport in magnetohydrodynamic duct flow regimes with conducting and insulating walls

TL;DR

This study uses DNS to analyze heat transfer in liquid metal duct flows under magnetic fields, considering wall conductivity and buoyancy effects, identifying four flow types and their heat transfer characteristics.

Contribution

It explores the combined effects of wall conductivity, buoyancy, and magnetic fields on flow regimes and heat transfer in liquid metal ducts, with implications for fusion reactor blankets.

Findings

Identified four distinct flow regimes based on wall conductivity and buoyancy.

Calculated Nusselt numbers for each flow type to assess heat transfer performance.

Analyzed statistical properties of heat transfer in different flow regimes.

Abstract

The flow of a liquid metal (LM) in a rectangular duct segment, subject to a uniform transverse magnetic field and uniform heating at the side walls is explored in an ample parameter space using Direct Numerical Simulation (DNS). We modify electrical wall conductivity, (either highly conducting or perfectly insulating) and investigate the effects of the buoyancy force, both in horizontally and vertically orientated ducts. In the latter case, it may be directed either with the flow or against the flow, creating backflow regions. In this parameter space and with the presence of vortex promoters at the inlet of the duct we identify $4$ types of flow. We calculate the Nusselt number $Nu(t)$ for each of them and study the statistical properties to compare their heat transfer capabilities in future fusion reactor blankets.