Comparison of Axial Flow and Swirling Flow on Particle Pickup in Horizontal Pneumatic Conveying

Pneumatic conveying is widely used in coal mining. As the lowest conveying velocity of materials, the pickup velocity is the key to the study of gas-solid two-phase flow. In this study, the pickup velocity of pebble particles was experimentally investigated. When the particle size is 3-9 mm, the airflow velocity was found to suitably describe the results as a function of the pickup velocity and have a high correlation. When the swirl number is 0.2, the optimal swirl number was found for which the highest particle pickup ratio was observed. Based on four different methods, namely, visual observation, mass weighing, coefficient of difference analysis, and determination of the peak-average ratio of the pressure drop in the flow field to measure the pickup velocity of the spraying material, the results showed that the accuracy of the particle pickup velocity obtained through visual observation was the lowest, and when the mass-loss rate of the particle was selected as the measurement index of the pickup velocity, the accuracy was the highest. The results will help to realize the long-distance transportation of spraying materials in inclined roadway under the shaft.

Automated summary

Pneumatic conveying is widely used in coal mining, and the pickup velocity is a key factor in the study of gas-solid two-phase flow. This study experimentally investigated the pickup velocity of pebble particles and found that the airflow velocity can suitably describe the relationship between pickup velocity and particle pickup ratio. The optimal swirl number for the highest particle pickup ratio was also determined. Different methods were used to measure the pickup velocity, and the accuracy was found to be highest when using the mass-loss rate of the particle as the measurement index. These findings contribute to the long-distance transportation of spraying materials in inclined roadways under the shaft.