Transients in Turbocompressors.
Final rept. Jan 75-Feb 76,
NORTH CAROLINA STATE UNIV RALEIGH ENGINEERING DESIGN CENTER
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This report describes the work done between the Spring of 1975 and February 1976 on a cooperative program between North Carolina State University and the United Technologies Research Center. The effect of unsteady flow on compressor performance is being investigated experimentally in the UTRC Large Scale Rotating Rig and theoretically at NCSU with a refined computer-based flow model. The goal of the program is to provide improved predictive techniques for use in turbocompressor design based upon an improved understanding of the basic coupling between distorted inlet flow, the onset and disappearance of rotating stall, and compressor stage performance. The diameter is 5 ft. with the maximum rotational speed of 600 RPM. The blade chord of 6 in. coupled with an inlet velocity of 100 ftsec gives a blade RE approx. 0.000005. Upstream screens provide a 20 sinusoidal variation in axial velocity once per revolution. Rotating instrumentation will measure steady and unsteady surface pressures on the rotor blade, the boundary layer behavior on the blade, and will allow a complete investigation of the 3-D properties of the near wake of the rotor. Stationary frame measurements will include mean and transient inlet and downstream conditions. A 45 channel slipring assembly, with on-board excitation and amplification electronics developed under this program will give high quality signals on 18 transient data channels. A refined theoretical flow model has been developed at NCSU for use in data interpretation, with runs planned for early spring. The program is continuing under a follow-on contract with the AFOSR. Author
- Fluid Mechanics
- Jet and Gas Turbine Engines