Compressor Blade Tolerance Optimization

1
Compressor Blade Tolerance Optimization

• Objectives
• Quantify sensitivity of compressor blade
  aerodynamic performance to geometric variability
  in terms of commonly used geometric parameters
• Develop a method for implementing performance
  based compressor blade tolerancing

• Method
• Inputs Blade geometries from manufacturing
  model
• Outputs
• Meanline aerodynamic performance (loss, incidence
  range)
• Geometric parameters (ex LE thickness, chord
  length, etc)
• Performance calculated using MISES
• Geometric parameters calculated using tolerancing
  program

2
Tolerance optimization

• Optimizing to minimize P(incorrect decision)
  P(accepting a bad blade) P(rejecting a good
  blade)
• Attempt to minimize P by setting and adjusting
  upper and lower bonds on geometric parameters
• Search for minimum of P using Matlabs FMINSEARCH
  algorithm and some educated guessing
• Best measured indicators of performance are LE
  thickness, TE thickness, and measures of quality
  of the LE curve

3
Preliminary Results

• Diagram shows performance parameters of interest.
• Histogram on right show performance of
  tolerancing scheme with acceptance limit set at 3
  StdDev from nominal. Blades are predominately
  sorted based on LE thickness.

Incidence at 2x Nominal Loss
Incidence at 2x Measured Loss
2x Min Nominal Loss
Aerodynamic Loss
Nominal Blade
Measured Blade
Min Nominal Loss
Measured Loss at Nominal Angle
Minimum Measured Loss
Angle of Incidence