The impact of pulsating parameters on particle dynamics in vertical pipe during hydraulic conveying with pulsating inlet flow

This paper presents a numerical investigation of the hydraulic conveying performance of coarse particles with the inlet pulsating fluid velocity in a vertical pipe. The influence of pulsating parameters, in terms of pulsating amplitudes and frequencies, on hydraulic conveying is mainly considered. The pulsations of particle and slip velocity are as periodic and regular as the inlet pulsating velocity. The variation of the normalized force in one pulsating time cycle is also analyzed. Then the laws of particle group distribution with transient time and vertical distance are obtained: the plug phenomenon is more obvious at the larger pulsating amplitude, further leading to pipe blockage, while a larger pulsating frequency is beneficial to the weakening of the plugs. Particle relaxation time is introduced to explain the changes in particle group distribution. Additionally, the temporal variations of flow fields are also used to illustrate the propagation of kinematic waves.