Experimental validation of indirect conduction theory and effect of particle roughness on wall‐to‐particle heat transfer
Experimental validation of indirect conduction theory and effect of particle roughness on wall‐to‐particle heat transfer
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DOI：
10.1002/aic.16703
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发表时间：
2019-10
期刊：
影响因子：
3.7
通讯作者：
I. Mishra;A. Lattanzi;C. Lamarche;A. Morris;C. Hrenya
中科院分区：
文献类型：
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作者：
I. Mishra;A. Lattanzi;C. Lamarche;A. Morris;C. Hrenya
在各种工业单元操作中，平壁与固体颗粒之间的传导对于传热是重要的。预测这种系统中的传热需要两种相关传热模式的理论：通过颗粒壁接触区域的传导（直接传导）和通过近壁区域中颗粒周围的间隙流体的传导（间接传导）。虽然前者的机制是很好的理解，后者缺乏实验探索。在这里，玻璃和钢颗粒填充床的实验传热系数与计算流体动力学-离散元方法模拟进行了比较，其中包括现有的间接传导理论。当颗粒的毕奥数（Bi）远小于1（钢）时，发现合理的一致性，但Bi ~ 1（玻璃）出现显著差异。此外，玻璃颗粒的表面形态被修改，以实验阐明粗糙度对颗粒壁传热的影响。
Conduction between a flat wall and solid particles is important to heat transfer in various industrial unit operations. Predicting heat transfer in such systems requires theories for the two relevant modes of heat transfer: conduction through the particle‐wall contact area (direct conduction), and conduction through the interstitial fluid surrounding the particles in the near‐wall region (indirect conduction). While the former mechanism is well understood, experimental exploration of the latter is lacking. Here, experimental heat transfer coefficients for packed‐beds of glass and steel particles are compared to computational fluid dynamics–discrete element method simulations, which include an existing theory for indirect conduction. Reasonable agreement is found when the particle Biot number (Bi) is much less than unity (steel), but significant differences occur for Bi ~ 1 (glass). Additionally, the surface morphology of the glass particles is modified to experimentally elucidate the effects of roughness on particle‐wall heat transfer.