关键词: 粉末输送;弯管;气固两相流;颗粒碰撞;铝粉;压力损失

Abstract: The bending pipe is an important part of the fuel delivery system of powder fuel ramjet. In order to study the flow field structure， collision effect and the variation rules of total pressure loss for gas-solid two-phase flow in bending pipe， with the collision force and elastoplastic deformation of particles were considered， the numerical simulation was carried out to investigate the flow status of aluminum powder in bending pipe by the CFD-DEM coupling method. The results show that， compared with the traditional two-fluid model and orbit method， the CFD-DEM algorithm can more accurately describe the collision information of particle flow and the change of two-phase flow field. With the increase of fluidizing gas flow rate， the trend of total pressure loss in the bending pipe decreases first and then increases. Under the conditions studied in this paper， the best mass flow rate of fluidizing gas is 6~7g/s（fluidizing gas velocity is 3.0~3.5m/s）. Under the low flow rate， the particle-particle collisions are much larger than particles-wall. With the increases of fluidizing gas velocity， particle-outer wall collisions increase rapidly， which causes that the particle-wall collisions exceed particle-particle collisions. It also shows that the larger the bending radius is， the greater the total pressure loss in the bending pipe is， but the collision numbers of particle-particle and particle-wall are reduced.

Key words: Powder conveying;Bending pipe;Gas-solid two-phase flow;Particle collision;Aluminum powder;Pressure loss