Experimental And Numerical Study On Viscosity Liquid And Dense Granular Jets Impingement On The Wall

This study investigated the characteristics of viscosity liquid and dense granular jets impingement on the wall. Firstly, the characteristics of the viscosity liquid sheet have been experimentally studied by a high-speed camera. The effects of Weber number, the viscosity of liquid and the diameter of the wall were investigated. Secondly, the process of dense granular jets impingement on the wall have been experimentally studied by a high-speed camera and numerically studied by engineering discrete element method (EDEM). The effects of velocity of the jet, diameter of the particle, diameter of the nozzle and the solid content on the granular sheet and surface waves were investigated. The liquid-like characteristic and reasons of the dense granular jet impingement on the wall have been researched. The main contents and results are summarized as follows:1. The shape of liquid sheet, the generation and propagation process of surface wave of liquid sheet were analyzed. The experimental results show that the viscosity of liquid and the diameter of wall have important impact on the shape of liquid sheets. As the viscosity increase, the size of liquid sheet become bigger. As the diameter of wall increase, the liquid sheet transforms the shape from the water bell to the hydraulic jump. At We> 1000, the surface wave appears on the liquid sheet. And the anti-symmetric wave plays an important role in promoting the liquid sheet breakup. The merging process happens along radial direction of liquid sheet.2. The shape of dense granular impingement on the wall, the generation and propagation process of surface wave of dense granular sheet were studied. The experimental results show that the dense granular jet impingement on the wall presents the liquid-like shape. As the diameter of particle increases, the solid content of dense granular jets decreases, and the interaction between the particle and air becomes intense, the dense granular jet impingement on the wall scatters to all directions. In additional, the surface wave appears on the granular sheet. Compared with the liquid sheet, the merging phenomenon becomes intense. The flux pulsation of granular jet is the main reason of the surface wave of dense granular jet impingement on the wall.3. The numerical simulation of dense granular jet impingement on the wall have been taken by the EDEM. The simulation results show that the opening angle and particle velocity of both simulation and experimental are in good agreement at different velocities of granular jets and diameters of particles. The simulation explains the reasons of granular sheet and scattering model well. Based on the space distribution, velocity distribution and energy distribution of the computational domain, we find that as the solid content increase, the probability of particle rebound decreases, the velocity and energy of particle is more uniform, and then the dense granular jet impingent on the wall presents the granular sheet easier.