Thermophysical and Elastic Wave Theory Approach to Thermal Contact Resistance of Solid Surfaces

材料固体表面的热接触电阻是热工程中工业器件热设计的重要因素之一。在热物理理论和弹性波理论的基础上，对接触热阻的物理机理进行基础性研究是必要的。同时，也有必要研究一种过程中技术来诊断/评估固体表面的热接触电阻，因为固体表面的热接触电阻是不断变化的。在本研究中，我们从这个角度进行了以下三项研究。首先，我们寻求一种从外部诊断固体-固体界面上的热接触电阻的原位技术。由于接触界面的微观结构随时间的变化取决于施加的压力和晶体结构的变形，因此开发一种评估接触状态的方法非常重要。在本研究中，我们将超声波技术应用于热接触电阻的裂纹搜索。我们对超声波在金属-金属接触界面上的反射和传热进行了宏观实验。其次，利用弹性波理论研究了超声波在介质界面上的反射和透射特性。即用弹性波理论描述了脉冲超声/弹性波或波包的传播与区分、超声波的界面反射、界面透射和衍射现象，完成了反演分析系统。我们对光滑表面和系统粗糙表面的超声波反射和透射特性进行了基础实验，验证了分析系统的能力。第三，从微观上研究了有限尺寸原子柱中非均匀热能流动的分子动力学。这样的研究必须是热接触电阻微观机理研究的基本单元。结果表明，在有限尺寸的原子微通道中，在通道表面影响有效的情况下，热能不是均匀流动，而是更多地向通道中心流动，这是产生接触热阻的主要因素之一。少

Thermal contact resistance of solid surfaces of materials is one of the most important factors in thermal design of industrial devices in thermal engineering. It is necessary to develop a fundamental study to clarify physical mechanism of thermal contact resistance on bases of thermophysical and elastic wave theory. At the same time, it is also necessary to study an in-process technique to diagnose/ evaluate thermal contact resistance of solid surfaces, which changes from time to time. In this study, we performed the following three studies from this point of view.First, we pursued an in-situ technique for diagnosing the thermal contact resistance on a solid-solid interface from outside. Since microstructure of the contact interface changes with time depending on applied pressure and deformation in crystal structure, it is important to develop an method for evaluating contact states. In this study, we applied an ultrasonic wave technique for crack-search to our thermal contact resistan … More ce problem. We made macroscopic experiments on ultrasonic wave reflection on a metal-metal contact interface and heat transmission through the interface. Second, we investigated ultrasonic wave reflection and transmission characteristics at an interface of media by an elastic wave theory. That is, we described propagation and distinction of pulse ultrasonic/ elastic wave or wave packet, interface reflection, interface transmission and diffraction phenomena of ultrasonic wave by an elastic wave theory and completed the inversion analysis system. We made basic experiments on ultrasonic wave reflection and transmission characteristics on smooth and systematically rough surfaces, and confirmed the ability of the analysis system. Third, we made a microscopic study of molecular dynamics on inhomogeneous thermal energy flow through a finite-size atom column. Such a study must be an elementary unit of a study on micromechanism of thermal contact resistance. It was demonstrated that in a micro-channel of atoms of a finite size, where influence of the surface of the channel is effective, thermal energy does not flow homogeneously but flows more in the center part of the channel and that it is one of the main factors of thermal contact resistance. Less