Three-component LDA measurements in an axial-flow compressor

A three-color, three-component laser Doppler anemometer (LDA) was used to simultaneously measure the three components of velocity in a low speed (2900 rpm), axial-flow-compressor, rotor-blade passage. It is demonstrated that accurate measurements in the mean motion are possible over much of the blade passage and that the secondary motions can be captured. Confirmation of the observed mean-flow results is obtained through a comparison of the three-dimensional flow with limited stationary pressure probe measurements and simple irrotational flow assumptions. The presentation of the measurements is followed by a discussion of the difficulties encountered in making simultaneous three-component velocity measurements in blade passages with LDA, and suggestions are made for improving the present system for this task.