Fig 1.
Effect of Bernstein and B-spline on profile control.
Fig 2.
Effect of Bernstein and B-spline on profile control.
Fig 3.
The mapping relationship between blade surfaces and Bezier surfaces.
Fig 4.
FFD technology.
Fig 5.
FFD parametric method modeling flow chart.
Fig 6.
Centrifugal compressor blade FFD method control body vertex distribution.
Fig 7.
Original impeller geometry: (a) front view, (b) Side view.
Table 1.
Aerodynamic parameters and geometrical dimensions.
Fig 8.
Grid-independence verification: (a) Mass Flow-Efficiency, (b) Mass Flow-Total Pressure Ratio.
Fig 9.
Comparison of numerical model calculation and experimental data: (a) Relative flow—Isentropic efficiency, (b) Relative flow—Total pressure ratio.
Fig 10.
Two-stage optimization process.
Fig 11.
Bezier surfaces control the distribution of vertices.
Table 2.
NSGA-IV optimization algorithm parameter configuration.
Fig 12.
Multi-condition global optimization process.
Fig 13.
Deformation cloud plot: (a) Main blade, (b) Splitter blade.
Table 3.
Aerodynamic performance of ROC before and after the global optimization.
Table 4.
Aerodynamic performance of NOC before and after the global optimization.
Fig 14.
Comparison of performance curves before and after global optimization for multiple operating conditions: (a) Flow Mass-Isentropic Efficiency, (b) Flow Mass-Total pressure ratio.
Fig 15.
Multi-condition local fine optimization process.
Fig 16.
FFD control body frame diagram.
Fig 17.
Isentropic efficiency distribution of the outlet: (a) ROC, (b) NOC.
Fig 18.
Optimization variable distribution chart: (a) Leading edge and middle design variables of the main blade, (b) Trailing edge design variables of the main blade, (c) Leading edge and middle design variables of the splitter blade, (b) Trailing edge design variables of the splitter blade.
Table 5.
Position of the optimization variable.
Fig 19.
Direction of change and range of change.
Fig 20.
Changes in main blades before and after optimization: (a) Change of leading edge and middle control point of main blade, (b) Change of trailing edge control point of main blade.
Fig 21.
Changes in splitter blades before and after optimization: (a) Change of leading edge and middle control point of splitter blade, (b) Change of trailing edge control point of splitter blade.
Fig 22.
ROC and NOC Performance Curve before and after optimization:(a) Mass Flow-Isentropic efficiency, (b) Mass Flow-Total pressure ratio.
Table 6.
ROC aerodynamic performance before and after optimization.
Table 7.
NOC aerodynamic performance before and after optimization.
Fig 23.
Entropy value of outlet S3 section after local optimization (NOC): (a) Original, (b) Optimized.
Fig 24.
Isentropic efficiency of outlet before and after local optimization (NOC).
Fig 25.
Relative Mach number of 90% height B2B surface before and after local optimization (NOC): (a) Original, (b) Optimized.
Fig 26.
Entropy of downstream outlet S3 section after local optimization (ROC): (a) Original, (b) Optimized.
Fig 27.
Relative Mach number of 30% height B2B surface before and after local optimization (ROC): (a) Original, (b) Optimized.
Fig 28.
B2B entropy of 90% blade height before and after local optimization (ROC): (a) Original, (b) Optimized.