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

液态金属（LM）是传热流体（HTF）在高热流密度和中高温应用中有前途的候选者。底层的物理传热机制强烈地受到LMs的高导热系数的影响，并且与空气和水等HTFs有很大的不同。尽管LMs作为HTFs的应用显示出提高效率的潜力，但缺乏关于LMs湍流传热的高保真数据。为了加深对所涉及的物理过程的理解，本文提出了一种扩展的、全面的数值分析方法，在前人关于强迫对流非均匀热边界条件的工作的基础上，接下来的步骤是增加浮力的影响（混合对流）以及热交换器的固体部分内的热传导（共轭传热）和热物理性质的温度依赖性。高保真度数值模拟将通过并行化的高阶开放源代码Nek 5000来执行，该代码已经过广泛测试，LM在两个不同的普朗特数，包括例如铅铋共晶（LBE）和钠（Na），是要研究的范围内的参数，涵盖不同的制度，在相反的和辅助的混合对流，以及不同的流体动力学操作条件。本研究的结果提供的信息，以延长调查的现象影响LM中的传热。 它们为测试和调整以及改进LM中湍流传热模型提供了重要的参考数据。

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.