A Method for Design of Silo Ejector Concerning with Wall Friction

Aiming at the problem of silo design, a quasi-one dimensional method concerning with wall friction was proposed based on the ejector function method. A mathematical model of wall friction was proposed and ejector functions and static pressure matching functions concerning with wall friction were established. The analysis results prove that the velocity at the stagnation critical point is less than sonic speed, the stagnation critical point of ejector can be achieved and the third critical point is impossible to achieve. And then, the characteristics were analyzed with practical examples, considering the engine total pressure, the cross-sectional area of the silo and the outlet pressure of the mixing chamber changed respectively, and the characteristic curves were drawn. The flow patterns of supersonic jet ejectors were analyzed by CFD method, considering respectively the engine total pressure, the cross-sectional area of the silo and the outlet pressure of the mixing chamber changed. At the same time, the inlet pressures of ejectors obtained by CFD were compared with that obtained by the quasi-one dimensional method. The results show that the errors between the CFD method and the quasi-one dimensional method are little on characteristic curves and their largest value is 4.31% when the backpressure changes, which verified the quasi-one dimensional method.