中文摘要：

根据垂直井筒煤粉沉降模型，设计了煤粉沉降试验装置，结合不同颗粒粒径和不同质量浓度下颗粒的沉降规律，利用试验得出的数据拟合出煤粉自由沉降末速公式，将试验给出的拟合公式与理论推导的沉降末速公式对比，修正了理论公式。试验结果表明，煤粉颗粒力学性能差，在垂直井筒沉降过程中易破碎，沉降时粒径会发生变化，使用砂粒的沉降公式进行研究时偏差较大。利用试验拟合的煤粉颗粒沉降公式对理论公式的系数进行了修正，修正后的公式可更好地反映煤粉颗粒在垂直井筒中的沉降规律，为新型排煤粉井下泵的设计提供依据。

英文摘要：

According to coal fines settlement model in the vertical wellbore, test apparatus for coal fines set- tlement is designed. Combined with the settlement law of coal fines with different particle size and different concen- trations, the terminal velocity formula for coal fines free settling is obtained using experimental data. Then, the theoretical terminal velocity formula is revised based on the formula got by the test. The test results show that the coal fines are prone to broken during settling in the vertical wellbore owing to their poor mechanical properties. Therefore, the sizes of the coal fines will change during settlement and would lead to a relatively large error while studying the coal fines settlement using sand settlement formula. The revised coal fines settling formula coefficient based on the test could better reveal the laws of coal fines settling in vertical wellbore, thus providing basis for design of novel downhole pump for coal fines removal.