Abstract: The primary objective of pneumatic conveying system design is to achieve energy-efficient, continuous, and stable material transportation, where the system performance is fundamentally governed by pressure drop characteristics. Although dense-phase pneumatic conveying exhibits superior transport efficiency and energy-saving potential compared to dilute-phase systems, its industrial application is constrained by complex gas-solid flow dynamics. These dynamics induce significant pressure fluctuations and unstable pressure drops, particularly in the horizontal conveying section downstream of the feeding outlet, which must be prioritized in system optimization. This study employs carbon black masterbatch as the experimental material and utilizes a pneumatic conveying cycle test bench to investigate the pressure drop characteristics in the horizontal feeding outlet section of the dense-phase system, focusing on steady-state pressure drop characteristic. Experimental protocols involve modulating rotary valve frequencies to generate solid-gas ratios ranging from 12 to 32, enabling the acquisition of pressure drop variation data in the feeding outlet section. Further analysis and prediction of total acceleration section pressure drop are conducted using empirical formulas and response surface methodology (RSM). The results show that the pressure drop of filling shoe is dominant in the pressure drop change of the filling shoe acceleration section L12, and both of them increase approximately linearly with the increase of solid-gas ratio. In the feeding outlet acceleration section L23, the prediction model of the pressure drop calculation coefficient (solid-phase friction coefficient) model is established by response surface method. When the solid-gas ratio is 12~26, the relative error between the model predicted pressure drop and the experimental value is within 15%. However, when the solid-gas ratio is 26~32, the pressure drop exhibits unstable fluctuation characteristics, and the prediction method based on the additional pressure drop method is no longer applicable.

Key words: pneumatic conveying, two-phase flow, response surface method, pressure drop, solid-phase friction coefficient, solid-gas ratio

摘要： 以较低成本使物料能够连续稳定输送是气力输送系统设计的目标。本工作以炭黑母粒为实验物料，基于气力输送循环试验台，对密相气力输送给料口加速段中加速压降和稳态压降的特性进行了研究。实验过程中通过改变旋转阀频率，得到了固气比为12~32时给料口加速段压降的变化数据，并采用经验公式和响应面法，对给料口加速段总压降进行了进一步分析和预测。结果表明，料靴压降在料靴加速段L12的压降变化中占主导地位，且两者均随固气比增大近似线性增加。在给料口加速段L23中，基于响应面法建立了压降计算系数(固相摩擦系数)预测模型，当固气比为12~26时，模型预测压降与实验值的相对误差在15%以内；当固气比增至26~32时，压降呈现不稳定波动特征，此时基于附加压降法的预测方法已不再适用。

关键词: 气力输送, 两相流, 响应面法, 压降, 固相摩擦系数, 固气比