Study on the Dynamic Thermal Contact Resistance and Its Evaluation

本文旨在了解滚动接触中圆柱表面动态接触热阻的物理机制。作为澄清这一复杂现象的第一步，静态接触圆柱表面的TCR已被详细研究。本文提出了一种计算TCR的瞬态方法，以便将其应用于动态情况。该技术用于估计由钢（S45 C）或铝合金（A6061）制成的辊的TCR值。对直径60 mm、长180 mm的接触辊，在10-120 kgf（98 ~ 1180 N）载荷条件下的TCR进行了一系列实验和计算评价。本研究的主要结论如下：（1）测量和估算的总TCR随辊上载荷的增加而减小。(2)在当前条件下，对于大于20 kgf的载荷，接触线处的微观收缩阻力变得可以忽略不计 关于我们 问题。相反，由于热流会聚到接触线的宏观收缩阻力在总体TCR中变得占主导地位。(3)这种宏观收缩阻力取决于接触线的宽度。宽度估计为约1.4-2.4毫秒，由弹性接触的赫兹理论给出的值。这种差异可能是由于表面上存在的粗糙度。(4)通过存在于接触表面之间的空气的传导热传递对总热传递具有重要贡献。（5）微观收缩阻力中接触电阻层热容的影响可以忽略不计，这表明滚动接触圆柱表面的整体动态TCR可以由静态微观TCR加上动态宏观TCR来计算，后者可以通过传统的计算方法进行数值预测。少

This study aims at understanding the physical mechanisms of dynamic thermal contact resistance (TCR) of cylindrical surfaces in rolling contact. As a first step to clarifying this complex phenomenon, the TCR of statically-contacting cylindrical surfaces has been investigated in detail. A transient method for the evaluation of TCR is developed with a view to applying it to the dynamic case. The technique is used to estimate the value of TCR for rollers made of either steel (S45C) or aluminum alloy (A6061). A series of experimental and computation evaluations is made for TCR of contacting rolls, whose dimension is 60 mm in diameter and 180 in length, under the loading conditions of 10-120 kgf(98-1 1 80 N). The conclusions gained by the present study are summarized as follows :(1) The total TCR measured and estimated decreases with load applied to the rollers.(2) Microscopic constriction resistance at a contact line becomes negligible for the load larger than 20 kgf under the present cond … More itions. Instead, macroscopic constriction resistance due to the heat flow's converging to the contact line becomes dominant in overall TCR.(3) This macroscopic constriction resistance is dependent on the width of the contact line. The width is estimated to be about 1.4-2.4 mes, the value given by the Hertz theory of elastic contact. This discrepancy is likely due to the roughness present on the surfaces.(4) The conduction heat transfer through the air present between the contacting surfaces has an important contribution to the overall heat transfer. The consideration of the rarefied gas effect is also important for very thin air layer near the contact line(5) The effect of heat capacity of the contact resistance layer responsible for the microscopic constriction resistance can be neglected.This suggests that the overall dynamic TCR of cylindrical surfaces in rolling contact may be evaluated from the static microscopic TCR plus the dynamic macroscopic TCR, the latter can be predicted numerically by conventional computational methods. Less