A geometrical–mechanical–thermal predictive model for thermal contact conductance in vacuum environment
A geometrical–mechanical–thermal predictive model for thermal contact conductance in vacuum environment
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DOI：
10.1177/0954405415611358
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发表时间：
2016-08
期刊：
影响因子：
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通讯作者：
Chi Ma;Liang Zhao;Hu Shi;X. Mei;Jun Yang
中科院分区：
文献类型：
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作者：
Chi Ma;Liang Zhao;Hu Shi;X. Mei;Jun Yang
本文建立了一个综合的几何-力学-热的粗糙表面接触热导预测模型。用Weierstrass-Mandelbrot分形函数对粗糙表面进行了表征。利用激光显微镜对试样的微观形貌进行了测量，确定了分形参数，并将其应用于力学和热模拟。提出了一种新的接触力学模型来计算接触参数，并考虑了微凸体与弹性、弹塑性和全塑性三种变形模式之间的不同接触尺度。法向接触压力应等于外载荷，它是给定表面的分形参数、最大接触面积和材料物理性质的函数。在接触力学模型的基础上，首先提出了一对接触微凸体，然后将多个接触微凸体组合起来，得到了接触总导热系数。利用该模型研究了接触载荷、表面粗糙度、微凸体顶部半径、接触面积以及温度对接触热导的影响。研究结果表明，接触热导随接触载荷和接触面积的增大而增大。表面粗糙度越大，接触热导率越小。最后，通过实验验证了接触导热模型的有效性。将该几何-力学-热力学预测模型与现有的两种预测模型及一系列实验数据进行了比较。计算结果与实验结果吻合较好，验证了模型的有效性，为进一步研究接触表面间的传热提供了依据。
In this article, a comprehensive geometrical–mechanical–thermal predictive model is developed for thermal contact conductance between two flat metallic rough surfaces. The rough surface was characterized by Weierstrass–Mandelbrot fractal function. The micro-morphology was measured by laser microscope to identify the fractal parameters that were then applied to mechanical and thermal modeling. A new contact mechanics model was then proposed to calculate the contact parameters, and different contact scales between asperities and three modes of deformation, elastic, elastic–plastic and fully plastic, were taken into account. The normal contact pressure, which should be equal to the exterior load, was formulated as a function of the fractal parameters, the maximum contact area and the material physical properties of the given surface. Based on the contact mechanics model, first a single pair of contacting asperities was proposed and then multi-contacting asperities were combined to get total thermal contact conductance. The influences of contact load, surface roughness, asperity top radius and contact area as well as the temperature on the thermal contact conductance were investigated by using the proposed model. The investigation results showed that thermal contact conductance increases with the contact load and contact area. The larger the surface roughness, the smaller is the thermal contact conductance. Finally, the experiments were conducted to validate the effectiveness of the thermal contact conductance modeling. This geometrical–mechanical–thermal predictive model was compared with the two existing predictive models and a series of experimental data. The results showed good agreement, demonstrating the validity of the model and providing certainty for further study on the heat transfer between contact surfaces.