Hi! I model axial compressor. Results near optimum point have good coincidence with experimental data. But they are very different for left and right parts of Pressure Ratio vs. Flow Rate curve. I had similar difficulty with centrifugal pump. So my questions are following. 1. What are the reasons of discrepancy between estimated and observed data? Can the separated flows and transient effects on non-optimal regimes be the main reasons? 2. What should I do to improve results? 3. Can CFD give good results for all curve (far from optimum too)? Thanks a lot for advices!

Georg,

The left and right parts of the performance chart are surge and choke area for compressor. Runs in these conditions are not as stable as optimum points. So it is normal to be different to the test data. I am also wondering the ways to improve CFD results. Maybe some other will show us some tips. ^_^