Next step towards high-fidelity numerical simulations of turbulent heat transfer to liquid metals: forced and mixed convection with non-uniform wall heat flux, conjugate heat transfer and temperature dependent thermophysical properties

• Applicant: Professorin Dr.-Ing. Bettina Frohnapfel
• Subject Area: Fluid Mechanics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 462658330

Liquid Metals (LMs) are promising candidates for Heat Transfer Fluids (HTFs) in applications where high heat flux densities and medium to high temperatures are present. The underlying physical heat transfer mechanism is strongly influenced by the high thermal conductivity of LMs and is substantially different from HTFs like air and water.Even though the application of LMs as HTFs show the potential of increasing the efficiency there is a lack of high-fidelity data on the turbulent heat transfer of LMs. In order to improve the understanding of the involved physical processes, an extended, thorough numerical analysis is proposed herein.Based on previous work on non-uniform thermal boundary conditions for forced convection, the next steps are to add the effects of buoyancy forces (mixed convection) as well as heat conduction within the solid part of the heat exchanger (conjugate heat transfer) and the temperature dependency of thermo-physical properties.The high-fidelity numerical simulations will be performed by the massively-parallelized, high-order, open source code Nek5000, which has been extensively tested, validated and shown to yield accurate results in the previous work.LM at two different Prandtl numbers, encompassing e.g. lead-bismuth eutectic (LBE) and sodium (Na), are to be studied over a range of range of parameters covering different regimes in opposed and aided mixed convection as well as different hydrodynamic operating conditions. The results of this study provide information to which extend the investigated phenomena influence heat transfer in LM. They provide essential reference data valuable for testing and tuning as well as improving models for turbulent heat transfer in LMs.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr.-Ing. Thomas Wetzel