University Research Initiative for Rotorcraft Engine Unsteady Aerodynamics
Abstract
Two problems driven by unsteady flow phenomena critical to advanced rotorcraft engines are addressed (1) The surge line must be extended to higher pressure ratios (2) Blade rows are susceptible to flow induced vibrations The onset and control of instability in low and high, speed centrifugal compressors was addressed Low speed experiments obtained unique detailed flow field data during a stall event Also, both passive dynamic and active control techniques for the suppression of rotating stall were investigated A unique facility representative of a high speed, high pressure ratio centrifugal compressor was developed in cooperation with Allison Gas Turbines Experiments were then performed to characterize the surge initiation process, including transient operation and passive control Experiments addressed the combined and simultaneous motion and gust induced unsteady aerodynamic response of compressor rotor blades from both flutter and forced response perspectives Also, PIV was used to obtain a time-history of the velocity field over a chordwise bending oscillating cascaded airfoil at design and off-design. Models were developed to analyze the unsteady flow, including separatation, through an oscillating cascade and also the feasibility of active suppression of nonlinear stall flutter using piezoelectric actuators, including limit cycle, chaotic and quasi-periodic separated flow induced vibrations
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1998
- Accession Number
- ADA365263
Entities
People
- Sanford Fleeter
Organizations
- Purdue University