Sensitivity investigation of a subsonic cascade performance to geometric deviations based on statistical method

Abstract

This paper has established an evaluation system for the sensitivity analysis of cascade/compressor aerodynamic performance to geometric deviations. The system includes blade profile parameterization with non-uniform rational B-spline (NURBS), uniform Latin hypercube sampling in association with Monte Carlo algorithm and statistical investigation methods. The sensitivity of a subsonic cascade performance to its geometric deviations is investigated under different typical inflow conditions. Results show that there is an approximately linear relationship between the geometric deviations and the aerodynamic parameters. The total pressure loss coefficient is the most sensitive to the leading edge profile deviation at i=2°. However the suction profile deviation and the leading edge profile deviation dominate the total pressure loss when the incidences are i = −4° and i = −8°. The blocking effect of the increased leading edge profile moves forward the separation point of the boundary layer. Therefore the scale of the separation vortex is enlarged, the total pressure loss is increased at i = 2° condition. Regarding i = −8°, the enlarged suction profile deviation reduces the circumferential static pressure gradient, resulting in an increase of the scale of separation vortex on the pressure side. The work is helpful to robust design of compressor blade profile and manufacturing & maintenance techniques of compressor blades.

Keywords

• geometric deviation
• statistical analysis
• spearman’s rank correlation
• sensitivity
• latin hypercube sampling