Numerical Simulation Of Dense Phase Pneumatic Conveying Of Slug Flow With Distinct Element Method

Dense phase pneumatic conveying of slug flow is widely applied in industry. Because of its complication, the detailed information of fluid flow has not been well understood. Besides, the numerical simulation on the process is seldom found in the literates, so it is worth to be studied from both theoretical aspect and engineering application aspect.In this dissertation, a dense phase gas-solid two-phase flow model is developed, which includes two parts: fluid model and solid particle model. In the model fluid field is obtained by solving N-S equation under Euler coordinate system, while solid particle movement is simulated by trajactory model under Lagrange coordinate system, where two-way coupling effect between gas and solid phase is considered. Distinct Element Method(DEM),a powerful tool in the mechanical analysis of discontinuous medium, is introduced to simulate the contact force between parti lcles. In order to test the accuracy of the model and the correctness of the programme, the free falling movement of particles and fluidized bed performance is calculated. The results are satisfactory.It is the first time that distinct element method attached in a Eulerian-Lagrangian model is used to numerically simulate pneumatic conveying of multi-slug flow in a horizontal pipe. The movement of the slug is reproduced in the simulation, which repeats the performance shown in experiment as a whole. Furthermore, effects of the innet velocity and initial length of slug are studied.The result indicates that DEM has wide prospects in numerical simulation of the dense solid-gas flow.