| In recent years, the study of inner flow of multistage compressor has become one of the main research areas in turbomachinery. This paper dealt with complex flow numerical simulation of the one blade channel which was abstracted from a centrifugal compressor's intermediate level. Combined with physical experiment data, the analysis concentrated on each part's inner flow characteristics and flow pattern.First, taking the experimental data of classical back step flow as foundation, the several turbulence models were compared with each other by amounts of simulating results data including velocity profile, pressure coefficient, friction coefficient etc, where grid quantity, time of calculation, CPU occupation were also considered. The standard k- model was ultimately selected for compressor single channel numerical simulation.The compressor model's impeller tip diameter is 400mm, Mach number is 0.8 and impeller rotating velocity is 13366 rpm. Experiment data was provided by some compressor enterprise's research center. The numerical analysis was carried out in nine working conditions. Results comparison showed that the performance parameters curves based on calculation were in line with the experiment curves, and the difference of the peak efficiency between them was less than 4 percent. Choosing three different flux coefficient operating conditions(one design condition and two off-design conditions), this paper analyzed internal flow characteristics of important parts such as impeller, diffuser, return channel etc in detail, also the contrast graphs of velocity distribution, pressure profile were given. By comparison, it was found that off-design operating conditions led to much loss and low efficiency while uniform flow pattern near the design conditions could postpone separation and have higher efficiency. The research results provided valuable numerical study data to the design approach, modification and optimization of centrifugal compressor. |
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