Aeromechanical Control of High-Speed Axial Compressor Stall and Engine Performance—Part II: Assessments of Methodology

Abstract

A theoretical assessment was made explaining how aeromechanical feedback control can be implemented to stabilize rotating stall inception in high-speed axial compression systems. Ten aeromechanical control strategies were quantitatively evaluated based on the control-theoretic formulations and dimensionless performance analysis outlined in the Part I companion paper (McGee and Coleman, 2013, “Aeromechanical Control of High-Speed Axial Compressor Stall and Engine Performance—Part I: Control-Theoretic Models,” ASME J. Fluids Eng., 135(3), p. 031101). The maximum operating range for each aeromechanical control scheme was predicted for optimized structural parameters. Predictability and changeability in the hydrodynamic pressure, temperature, density, operability, and aeromechanical performance of dynamically-compensated, high-speed compressor maps of corrected pressure, corrected mass flow, corrected speeds, temperature ratios, and optimum efficiency were compared for the various aeromechanical control strategies. Compared with dynamically-compensated, low-speed compressor maps of pressure rise and flow coefficient (Gysling and Greitzer, 1995, “Dynamic Control of Rotating Stall in Axial Flow Compressors Using Aeromechanical Feedback,” ASME J. Turbomach., 117(3), pp. 307–319; McGee et al., 2004, “Tailored Structural Design and Aeromechanical Control of Axial Compressor Stall—Part I: Development of Models and Metrics, ASME J. Turbomach, 126(1), pp. 52–62; Fréchette et al., 2004, “Tailored Structural Design and Aeromechanical Control of Axial Compressor Stall—Part II: Evaluation of Approaches,” ASME J. Turbomach., 126(1), pp. 63–72), the present study shows that the most promising aeromechanical designs and controls for a class of high-speed compressors were the use of dynamic fluid injection. Dynamic compensations involving variable duct geometries and dynamically-re-staggered IGV and rotor blades were predicted to yield less controllability under high-speed flow environments. The aeromechanical interaction of a flexible casing wall was predicted to be destabilizing, and thus should be avoided in high-speed compression systems as in low-speed ones by designing sufficiently rigid structures to prevent casing ovalization or other structurally-induced variations in tip clearance.

Fluid Dynamics of a Bistable Diverter Under Ultrasonic Excitation—Part I: Performance Characteristic

“…Over the last two decades this has led to a renaissance in flow control research focusing on both passive and active methods. The variety of applications and concepts is vast and includes boundary layer separation control [1][2][3][4][5][6][7], drag reduction of ground vehicles [8][9][10], unsteady film cooling [11,12], combustion instability control [13], jet vectoring [14], mixing enhancements [15,16], cavity tone and resonance suppression [17,18] as well as the control of secondary flow phenomena in inlet ducts or highly loaded compressors and turbines [19][20][21][22][23]. The enormous amount of published articles regarding different strategies and applications demonstrate not only the huge interest within the aerospace community but also the difficulties and challenges that still FE-20-1221, MAIR persist.…”