Local Friction Forces between Plug and Pipe Wall in Dense Phase Pneumatic Conveying

Dense phase pneumatic conveying is widely used to transport granular materials or powder due to its efficiencies gained on cost and abrasion and erosion. To date these systems have been designed and analyzed using average frictional representation for the conveyed plug. This study explores the effect of this friction force by measuring strains on the pipe wall when the plug is moving passed the region where strain gauges installed on the outer pipe wall. Strains on axial direction of plug flow measured from four different locations, top, bottom, front side, and backside of outer pipe wall. Dynamics strains with the sampling frequency of 10 KHz were measured by using data acquisition card with related software. With this strain, the frictional force can be determined. In this study, comparison the magnitude of the strain under different plug length, and different material transported will be presented. It was found that the magnitude of the axial direction of strain due to the frictional force was affected on the length of the plug. In addition, it was found that the magnitude of strain was different with its measuring location. The plug can now be models with realistic frictional representation of the conveyed plug. Finally, the voidage variation within the plug was calculated based on the Ergun’s Equation.