ABSTRACT The Ergun equation is commonly used to predict velocity-pressure drop behaviour in packed beds. For many particular systems, the measurements deviate significantly from this relationship. Because of this, the equation is often treated as a purely empirical relationship, and its factors as fit parameters. This paper shows that the physics-based model underlying the Ergun equation should be treated by careful investigation of the included parameters. It is shown that discrepancies between experiment and theory for particle collectives in the millimetre range and above are caused by insufficient methods to determine the specific surface area. This effect is especially large for coarse particles with very rough surfaces. As a 2D measurement method, dynamic image analysis can not provide a good measure of specific surface area. It does not account for both macroscale particle shape and microscale surface roughness, which is confirmed by an analysis of 3D particle measurements from X-ray microscopy.

中文翻译：

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通过粗颗粒床的气流：比表面积的作用

摘要 Ergun 方程通常用于预测填充床中的速度-压降行为。对于许多特定系统，测量值明显偏离这种关系。正因为如此，方程通常被视为纯粹的经验关系，其因子作为拟合参数。本文表明，应该通过仔细研究包含的参数来处理 Ergun 方程背后的基于物理的模型。结果表明，毫米级及以上粒子集合的实验与理论之间的差异是由确定比表面积的方法不足造成的。对于具有非常粗糙表面的粗颗粒，这种影响尤其大。作为一种 2D 测量方法，动态图像分析不能很好地测量比表面积。