The dynamic response of the compression system is a key factor in determining the operability characteristics of an aircraft gas turbine engine subjected to various transient environmental and control inputs. Computer models have been developed to simulate this response. The primary inputs to these models are the wide-range, steady-state compressor stage characteristics. To reduce the dependence of these dynamic models on experimental performance data, significant effort has been devoted to the development of stage characteristic prediction techniques.
As part of this ongoing effort, a model to simulate rotating stall inception and development in axial-flow compressor stages was constructed. This model was applied to an isolated rotor build to investigate the sensitivity of the predicted stall behavior to the shape of the high-incidence portions of the blading relative total pressure loss and turning angle characteristics, as well as to the rotor speed. In addition, the predicted steady-state, stalled rotor performance was compared with corresponding low-speed, experimental data.
By superimposing small flow perturbations on the rotor flow field over a range of initial operating conditions, it was demonstrated that stall inception occurs only for initial relative flow incidence near some critical value, defined as the incidence for which the relative total pressure losses incurred in the blade passage increase sharply. For initial operating points away from the critical one, no propagating disturbance was predicted. Also, a strong sensitivity of the predicted stall behavior to the shape of the high-incidence portion of the relative total pressure loss characteristic was observed with increased-slope curves resulting in earlier stall inception and larger amplitude stall disturbances. The effect of increased-slope loss curves on the predicted steady-state rotor performance was to cause a more abrupt drop in the flow and total pressure rise coefficients at the stall limit. Comparatively, varying the shape of the turning angle characteristic or the rotor speed had only a slight effect on the simulated rotating stall phenomena. Finally, the predicted install total pressure characteristic for a selected low-speed case was compared with experimental data with favorable results. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/44165 |
| Date | 04 August 2009 |
| Creators | Nowinski, Matthew C. |
| Contributors | Mechanical Engineering |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | xv, 103 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 28912199, LD5655.V855_1993.N697.pdf |
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