Abstract

LEWIS, K. L.. Prediction of stall inception in an axial flow compressor. R&D j. (Matieland, Online) [online]. 1991, vol.7, pp.19-25. ISSN 2309-8988.

The small perturbation stability analysis of Nenni and Ludwig [1] to predict stall inception of a high hub-to-tip ratio blade row was extended by establishing the blade row compatibility equations in the relative frame of reference and applying them to a diffusing control volume. This control volume represents a simplified form of the flow passage found between two blades in a compressor rotor or stator. The model predicts a neutral stability point at which a disturbance is neither amplified nor damped, as well as the frequency of the resulting disturbance. The model was applied to a rotor in a single stage environment for which extensive experimental data was available. The correlation of experimental and model results was acceptable. Stall inception was predicted in terms of stalling inlet angle to within 0,5 degrees in the tip region. The corresponding disturbance velocity was predicted as 0,56 blade speed compared to the measured value of 0,62 for the complete annulus. The predictive capability of the model was found to be very sensitive to the blade row performance characteristic. A parametric study was performed to study the influence of the area ratio of the diffusing control volume. It was found that an increase in area ratio of the diffusing passage tended to delay stall inception but decrease the disturbance velocity.

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