Compressor Stall :: Essays Papers

Compressor StallGas turbine locomotive engine performance is express mail by aerodynamic instabilities called rotating booth and surge. Currently there are several(prenominal) aver strategies for enhancing the operability boundary of laboratory compressors by actively controlling rotating stall and surge. Models which capture the qualitative behavior of the aerodynamic instabilities have been found to read abundant dynamic behavior and to be useful for designing control laws. Operability boundary is defined as the operating point where steady axisymmetric race is unstable and untolerable amount of rotating stall and surge is present in the arrangement. Operability sweetening is defined as the gap between the operability boundary for the controlled system and that for the unrestrained system. Operability enhancement is one of the main goals for active control of rotating stall and surge. Actuator limits and system noise are found to limit the operability enhancement. We are i nterested in two problems Analysis problem given a controller with actuator limits and plastered noise level, find the operability enhancement Synthesis problem given a set of controllers with actuator limits and certain noise level, find one that maximize the operability enhancement. It turns bug out that the synthesis problem is a minimax problem. We try to answer the analysis problem and the synthesis problem by nonlinear diminution using bifurcation hypothesis and invariant entangled theory. For stall control with bleed valve actuators, we have derived analytical formulas that agree qualitatively with the experimental results on a low zip rig. We have solved the synthesis problem for the case when surge line of descent is close to stall inception by normal form reduction for a low order compressor model. We are also interested in extending the above control problems to general dynamical systems. We think center manifold reduction and normal form reduction are potential t ools.Gas turbine engine performance is limited by aerodynamic instabilities called rotating stall and surge.