Experimental investigation of coupled MHD and thermal radiation effects in Rayleigh-Bénard Convection

瑞利-巴姆纳德对流（RBC）一直是流体流动和传热领域的一个经典课题。随着科学技术的发展和进步，以及学科的交叉适应，即使经过一百多年的研究，RBC也出现了新的内容和挑战。例如，在新兴的可再生能源研究领域和传统的航空航天领域，电磁场和/或热辐射对流体流动和传热的影响已经不能忽视。本课题旨在开展热辐射和电磁场共同作用下红细胞内流体流动和换热的基础实验研究。建议的模型实验应由各自的数值模拟来支持，而这些数值模拟不属于本建议的资助对象。在这里，已经可用和经过验证的磁场影响下RBC的内部代码将进一步开发，以包括热辐射的影响。在以导电流体和高温操作为特征的系统中，尚未进行系统的基础研究。根据工作经验和现有的实验基础设施，实验研究将集中在高达600 K的温度范围和高达5 t的强外磁场的影响上，在本研究计划的框架内，将与大连理工大学李本文教授建立非正式合作。在大连，重点是在没有磁场的情况下，研究远远超过600 K的高温辐射效应。系统揭示了传热与流体流动的精确关系，即努塞尔数和雷诺数对控制参数瑞利数（热驱动）、普朗克数（热辐射）和哈特曼数（磁场）的依赖关系。并结合临界参数探讨了流体从经典流态向极限流态转变的可能性。结合工程应用，分析高温储热系统和液态金属电池的不稳定性，并提出抑制不稳定性的技术。

Rayleigh-Bénard Convection (RBC) has been being a classical topic in the area of fluid flow and heat transfer. With the development and progress of science and technology, as well as the cross accommodation of disciplines, new contents and challenges appear in the RBC even after more than one hundred years’ researching. For instance, in the newly arising area of renewable energy research and the traditional aerospace area, the influences of electromagnetic field and/or thermal radiation on fluid flow and heat transfer cannot be ignored anymore. The present research proposal aims to conduct fundamental experimental research of fluid flow and heat transfer in RBC influenced by the combined effects of thermal radiation and electromagnetic fields. The proposed model experiments shall be supported by respective numerical simulations that are no subject for funding within the present proposal. Here, already available and validated in-house codes for RBC under the influence of magnetic fields will be further developed to include the effects of thermal radiation. Systematic fundamental studies in systems, characterized by electrically conducting fluids and high temperatures of operation, have not been performed yet. According to the working experience and the already existing experimental infrastructure the experimental investigations will focus on the temperature range up to 600 K and on the influence of strong external magnet fields up to 5 T. In the frame the present research proposal, an informal cooperation with Prof. Benwen Li of Dalian University of Technology Chinese will be established. At Dalian, the focus will be on the study of high-temperature radiation effects well beyond 600 K in the case when magnetic fields are absent. The precise relations of heat transfer and fluid flow, i.e. the dependence of Nusselt number and Reynolds number on the control parameters Rayleigh number (thermal driving), Planck number (thermal radiation) and Hartmann number (magnetic field) will be systematically revealed. Moreover, the possibility of fluid flow transformation from classical regime to ultimate regime will be explored together with the critical parameters. Combining with engineering applications, the instabilities in high-temperature thermal storage systems and liquid metal batteries will be analyzed, and techniques will be proposed to suppress them.