Abstract For the reliable design of a pneumatic conveying system, accurate estimation of solids friction factor through horizontal straight pipe is of paramount interest. Although the “straight pipe” method is fundamentally more appropriate, the “back calculation” approach provides several practical advantages for testing and modeling. However, earlier literature reports that “back calculation” approach suffers from 40 to 150% inaccuracy in prediction of total pipeline pressure drop in scale-up pipes, which had been discouraging for its use. In the present work, it has been argued that much of the criticism for the inaccuracy of back calculation method lies with the choice of its format of modeling solids friction factor. In this paper, “back calculation” method of modeling has been used by employing a “two layer” model format for solid friction factor for fly ash, ESP dust and cement. These models, when scaled up to predict the total pipeline pressure drop in larger and longer pipelines, have resulted in overall deviation from experimental data ranging from 3 to 35%, which is a significant improvement in prediction capability. The results prove that the selection of a better format of model for solids friction factor could significantly improve the reliability of “back calculation” method.

中文翻译：

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细粉流化密相气力输送的固体摩擦因数测试和建模程序评估

摘要 对于气力输送系统的可靠设计，通过水平直管准确估算固体摩擦系数至关重要。尽管“直管”方法从根本上来说更合适，但“反向计算”方法为测试和建模提供了几个实际优势。然而，较早的文献报道“反向计算”方法在预测放大管道中的总管道压降时存在 40% 到 150% 的不准确率，这一直不利于其使用。在目前的工作中，有人认为，对反向计算方法不准确的批评主要在于其建模固体摩擦系数的格式的选择。在本文中，通过对粉煤灰、ESP 粉尘和水泥的固体摩擦系数采用“两层”模型格式，使用了“反算”建模方法。这些模型在放大以预测更大和更长管道中的总管道压降时，导致与实验数据的总体偏差为 3% 至 35%，这是预测能力的显着提高。结果证明，选择更好的固体摩擦系数模型格式可以显着提高“反算”方法的可靠性。