Chaotic time series analysis tools for identification and stabilization of rotating stall precursor events in high speed compressors.

摘要

This research is a culmination of analytic and experimental results in the application of chaotic time series methods for rotating stall precursor identification in transonic compressors. This is the first known application of such techniques in a turbomachinery application. The nonlinear analysis methods used in this research are distinguished from previous methods in that they use a single pressure transducer to capture the fluid physical dynamics to detect stall inception behavior. The major objective of this research is two-fold: to present a new technique for stall precursor identification in high speed compressors and to reveal through preliminary open-loop control testing that nonlinear instabilities can be controlled through jet injection. The technique to be researched is a pseudo-correlation integral method referred to as the correlation method. To provide a basis for comparison, the traveling wave energy technique, which has been used extensively to study pre-stall data, is also briefly presented and applied. The correlation method is shown to have a potential advantage over the traveling wave energy method, because it uses a single sensor for detection and requires no predisposition of the data to distinguish changes in the behavior of the compressor. The correlation integral method will identify incipient stall formation (or varying dynamics in the compressor) for data captured from many compressor configurations. The compressors used include the NASA Lewis single stage high speed compressor, the Allied Signal T-55 axi-centrifugal multistage core compressor, and the NASA CC3 high speed centrifugal compressor. An additional method, the structure function algorithm, is also shown as a single sensor incipient stall detector. Both these algorithms are successful in the prediction of compressor stall. A control example in the final chapter using reduced order, high velocity, jet injection is shown to reduce stalling mass flow of the compressor. It is concluded that a single sensor stall detector may be used in conjunction with a small array of air injectors to control rotating stall.