Numerical Simulation of Unsteady Discharge Flow with Fluctuation in Positive Discharge Blower
The operating performance of positive discharge blower/s markedly influenced by the pulsation of the discharge flow, but difficult to be measured with experimental methods. The internal and discharge flow of positive discharge blower with involute type three-lobe are numerically investigated, both in air cooling and countercurrent cooling conditions by means of computational fluid dynamics (CFD). The unsteady compressible flow equations are solved using RNG κ-ε turbulent model. The finite difference method and the second order upwind difference scheme are applied into discrete equations. In the numerical simulation, the dynamic mesh techniques are used to approach the rotating displacement of cell cubage and the alterability of inlet, outlet flow area. The non-uniform mesh is applied to the rotor-stator coupled area. The reliability of the numerical method is verified by simulating the inner flow and comparing with the semi-empirical theory. The flow flux curves and the distributing of velocity vector showed obvious vortex motion in all the discharge process, both in air cooling and countercurrent cooling conditions. These vortexes with different positions, intension and numbers at different rotating angles have remarkable influences on the discharge flux. For air cooling, the vortex produced a second pulsation with big-amplitude in a cycle, and led to the early appearance of maximum of backflow. For countercurrent cooling, the frequency of pulsation increased due to the pre-inflow, but the hackflow at the outlet is prevented, also the pulsation strength has greatly decreased.......
【作者名称】: LIU Zhengxian
, WANG Dou
, XU Lianhuan
【作者单位】: School of Mechanical Engineering, Tianjin University, Tianjin 300072, China
, State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
, Xi'an Shaangu Power Co., Ltd, Xi'an 710075, China
, School of Mechanical Engineering, Tianjin University, Tianjin 300072, China
, Shandong Power Equipment Company, Jinan 250022, China
【关 键 词】: Numerical Simulation of Unsteady Discharge Flow with Fluctuation in Positive Discharge Blower
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