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Theory of finite disturbances in a centrifugal compression system with a vaneless radial diffuser
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Moore, F. K. |
| Copyright Year | 1990 |
| Description | A previous small perturbation analysis of circumferential waves in circumferential compression systems, assuming inviscid flow, is shown to be consistent with observations that narrow diffusers are more stable than wide ones, when boundary layer displacement effect is included. The Moore-Greitzer analysis for finite strength transients containing both surge and rotating stall in axial machines is adapted for a centrifugal compression system. Under certain assumptions, and except for a new second order swirl, the diffuser velocity field, including resonant singularities, can be carried over from the previous inviscid linear analysis. Nonlinear transient equations are derived and applied in a simple example to show that throttling through a resonant value of flow coefficient must occur in a sudden surge-like drop, accompanied by a transient rotating wave. This inner solution is superseded by an outer surge response on a longer time scale. Surge may occur purely as result of circumferential wave resonance. Numerical results are shown for various parametric choices relating to throttle schedule and the characteristic slope. A number of circumferential modes considered simultaneously is briefly discussed. |
| File Size | 2000279 |
| Page Count | 72 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910004145 |
| Archival Resource Key | ark:/13960/t3zs7nf12 |
| Language | English |
| Publisher Date | 1990-12-01 |
| Access Restriction | Open |
| Subject Keyword | Aircraft Propulsion And Power Vaneless Diffusers Throttling Nonlinear Equations Small Perturbation Flow Velocity Distribution Rotating Stalls Displacement Boundary Layer Separation Flow Stability Flow Coefficients Centrifugal Compressors Flow Distribution Inviscid Flow Singularity Mathematics Resonance Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
