Study on Wall Slip in Pipeline Flow of Dense Paste

Abstract

The apparent wall slip flows of incompressible and viscoplastic fluids in plane pipeline were analyzed assuming that the apparent slip layer consists solely wall slip layershear layerslug flow part and they are independent of the flow rate. Taking coal slurry for example,the experiment is conducted on pressure pipe rheological and resistance characteristic test system. It studies how two key factors (the particle concentration and the pipe diameter) influence the dense paste wall slip velocity. The assumed apparent slip mechanism provides methodologies for the determination of the slip velocity values that are consistent with the traditional Mooney method and furthermore allows the determination of the true shear rate of the dense paste at the wall and the yield stress. The analysis of the slip data of various dense pastes of rigid particles reveals that the apparent slip layer thickness is related to the particle concentration and the pipe diameter.