Liu Ruitao,Xu Zhong
(Institute of Fluid Machinery,Xi'an Jiaotong University,Xi'an 710049,China)
Abstract: The time marching method is adopted to solve the governing equations,and the computational analysis to the flow field in a centrifugal compressor with shrouded impeller,vaneless diffuser,bend and return channel compressing perfect and real gas respectively,is carried out,where the three-dimensional N-S code with the Yang & Shih two-equation turbulence model is employed,and a user-defined real gas property program is applied for the thermodynamic analysis.The calculations are performed with a central space discretization scheme and second/fourth order artificial dissipation terms.A special attention is focused on the flow characteristic of the bend and return channel, the different distribution pattern of the flows in compressor compressing the perfect and real gas.The simulated results demonstrate that the flow parameters in the outlet of the impeller compressing real gas are quite different from that compressing perfect gas and the differences are observed mainly near the hub and shroud of the impeller. The static pressure coefficient along the bend and the return channel for the perfect gas is higher than that for the real gas.The characteristic of the compressor compressing real gas approaches more closely to the experimental data.
Keywords: real gas; close impeller; flows of the stage; numerical analysis; full multigrid