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摘要
本文基于热力比拟的思路提出了一种新型颗粒间接触导热热阻模型，通过假设热通量在接触表面上的分布类似于应力的分布，消除了传统热阻模型在接触边缘处温度奇异性的问题。该模型在基本堆积方式和实际堆积方式下与现有的理论公式和实验进行比较，验证了使用该热阻模型预测颗粒材料导热系数的可行性。将该热阻模型运用到热离散单元法中，分析了高温试验装置内卵石床的温度和有效导热系数分布。由热传导方式得到的平均有效导热系数在20 kW和82 kW功率输入时分别为2.99和2.61 W/m·K。对于该空心圆柱构成的球床，当外壁温度从200 °C增加到1000 °C时，有效热扩散系数大约增加了20%。
Abstract
This study introduces a novel particle-to-particle contact thermal resistance model, which is developed based on the concept of analogical correspondence between force dynamics and heat transfer phenomena. By presuming a likeness between the distribution of heat flux across the contact surface and the distribution of stress, the issue of temperature singularity at the contact edge is effectively mitigated. The proposed model undergoes rigorous validation against existing theoretical frameworks and experimental data, exhibiting commendable concurrence. Furthermore, the combined utilization of this model alongside the thermal discrete element method is employed to scrutinize the temperature profiles and effective thermal conductivity distributions within a pebble bed confined within a high-temperature test unit. The computed average effective thermal conductivity values, derived from thermal conduction analyses, stand at 2.99 W/m·K and 2.61 W/m·K for power inputs of 20 kW and 82 kW, respectively. Remarkably, a notable approximately 20% augmentation in effective thermal diffusivity is observed as the outer wall temperature ascends from 200 °C to 1000 °C.
| 关键词 | 热力比拟，接触热阻模型，热离散单元法，有效导热系数，有效热扩散率 |
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| Keywords | thermal analogy, contact thermal resistance model, thermal discrete element method, effective thermal conductivity, effective thermal diffusivity |
