Influence of Variable Geometry Compressor on Transient Performance of Counter-Rotating Open Rotor Engines

Abstract

This work describes a methodology used for counter-rotating (CR) propellers performance estimation. The method is implemented in an in-house program for gas turbine performance prediction, making possible the simulation of the counter-rotating open rotor (CROR) architecture. The methodology is used together with a variable geometry compressor control strategy to avoid surge conditions. Two cases are simulated under transient operation for both fixed and variable geometry compressor. The influence of the variable geometry control on the transient performance of CROR engines is evaluated and a comprehensive understanding on the transient behavior of this type of engine could be obtained. It is shown that the use of the variable geometry compressor control does not significantly affect the overall engine performance, while avoiding the surge conditions, thus ensuring the engine operation safety.

Transient Behavior in Variable Geometry Industrial Gas Turbines: A Comprehensive Overview of Pertinent Modeling Techniques

“…The purpose of some the studies is merely model synthesis, i.e., only model development at certain operational behavior, while rest of the studies cover model analysis, i.e., FDD, prognostics, condition monitoring, and control system design as mentioned in the introduction section. Recently, Silva et al [ 60 ] have developed a transient model for a three-shaft counter rotating open rotor (CROR) marine engine. The intended purpose of this research was to observe the effect of VIGV angle modulation on the load change transient, i.e., load increase (acceleration) and load decrease (deceleration), and incorporation of VIGVs resulted in increased surge margin during load increase phase.…”