Mr. Feulner et al., MODELING FOR CONTROL OF ROTATING STALL IN HIGH-SPEED MULTISTAGE AXIALCOMPRESSORS, Journal of turbomachinery, 118(1), 1996, pp. 1-10
Using a two-dimensional compressible flow representation of axial comp
ressor dynamics, a control-theoretic input-output model is derived, wh
ich is of general utility in rotating stall/surge active control studi
es. The derivation presented here begins with a review of the fluid dy
namic model, which is a two-dimensional stage stacking technique that
accounts for blade row pressure rise, loss, and deviation as well as b
lade row and interblade row compressible flow. This model is extended
to include the effects of the upstream and downstream geometry and bou
ndary conditions, and then manipulated into a transfer function form t
hat dynamically relates actuator motion to sensor measurements. Key re
lationships in this input-output form are then approximated using rati
onal polynomials. Further manipulation yields an approximate model in
standard form for studying active control of rotating stall and surge.
As an example of high current relevance, the transfer function from a
n array of jet actuators to an array of static pressure sensors is der
ived. Numerical examples are also presented including a demonstration
of the importance of proper choice of sensor and actuator locations, a
s well as a comparison between sensor types. Under a variety of condit
ions, it was found that sensor locations near the front of the compres
sor or in the downstream gap are consistently the best choices, based
on a quadratic optimization criterion and a specific three-stage compr
essor model. The modeling and evaluation procedures presented here are
a first step toward a rigorous approach to the design of active contr
ol systems for high-speed axial compressors.