稠密颗粒系统辐射换热算法研究

Study on Particle Thermal Radiation Algorithm in Dense Granular Systems

本文在不同空间尺度下研究稠密颗粒系统的辐射换热,提出短程辐射模型、长程辐射模型和微观模型.长程辐射模型考虑了所有存在辐射换热关系的颗粒对,而短程辐射模型仅考虑距离较近的颗粒球。通过和现有的经验关联式比较,当材料热导率远大于辐射等效热导率时(Λ>10),长程辐射模型能准确地预测辐射换热。而当两者在同一量级上时,辐射换热被严重高估。此时,短程辐射模型显示出更好的计算精度,

In this paper, particle thermal radiation of dense granular systems under different spatial scale is investigated and short-distance radiation model, long-distance radiation model and microscopic model are presented. All possible particle pairs related by thermal radiation are considered in long-distance radiation model and only the ones which are very close to each other are taken into account in short-distance radiation model. By comparing the results with empirical correlations, long-distance radiation model can predict particle thermal radiation in good accuracy when solid conductivity is far greater than effective thermal conductivity （A 〉 10）. But when the conduetivities are in the same order, particle radiation is overestimated greatly in long-distance radiation model. And then short-distance radiation model provides good prediction for particle radiation.