Flow control method and means
First Claim
1. A method of controlling gas flow in a compressor comprising the steps of sensing the flow at a series of circumferentially spaced positions at a chosen axial station in a direction of flow through the compressor to detect variations in the flow above a predetermined limit of variation and, upon at least one of the variations being detected, injecting higher-pressure gas from a region downstream of said chosen station into the flow through the compressor upstream of said region generally in said direction of flow and in a circumferentially selective manner dependent upon the circumferential origins of said variations, to act against flow disturbances indicated by said variations.
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Accused Products
Abstract
The method controls gas flow in an axial flow compressor in which the flow at one or more chosen station in the direction of flow through the compressor is sensed at a series of circumferentially spaced positions. Flow variations above a predetermined limit are evaluated to initiate a response if a disturbance above a predetermined acceptable level is detected. When such a disturbance is detected, higher pressure gas bled from downstream is injected at a station to supplement the main gas flow. An incipient rotating stall cell will appear as a variation occurring sequentially at the circumferentially spaced positions. By responding to such a condition with a pressure injection, it is found possible to suppress both rotating stall and surge conditions in the compressor before this disturbance develops fully. The same method can be arranged to counter steady state distortion.
69 Citations
33 Claims
- 1. A method of controlling gas flow in a compressor comprising the steps of sensing the flow at a series of circumferentially spaced positions at a chosen axial station in a direction of flow through the compressor to detect variations in the flow above a predetermined limit of variation and, upon at least one of the variations being detected, injecting higher-pressure gas from a region downstream of said chosen station into the flow through the compressor upstream of said region generally in said direction of flow and in a circumferentially selective manner dependent upon the circumferential origins of said variations, to act against flow disturbances indicated by said variations.
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16. A method of controlling gas flow in a compressor comprising the steps of sensing the flow at a series of circumferentially spaced positions at a chosen axial station in the direction of flow through the compressor to detect variations in the flow above a predetermined limit of variation, the sensing of said variations at a series of said positions in circumferential sequence actuating the injection of gas at a higher pressure than that prevailing at said station to act against a flow disturbance indicated by said variations, and performing the gas injection in a series of different sectors around the compressor, said injection being generally in said direction of flow through the compressor and the flow being independently sensed in each of said sectors.
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17. A method of controlling gas flow in a compressor comprising the steps of sensing the flow at a series of circumferentially spaced positions to detect a variation in the flow in one circumferential region relative to another and, upon the variation being detected injecting, generally in the direction of flow through the compressor, higher-pressure gas from a region downstream of said series of circumferentially spaced positions toward a circumferential region in which said variation has been detected.
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18. Apparatus for controlling gas flow in a compressor comprising flow sensing means for a series of circumferentially spaced positions at a chosen axial station in a direction of flow through the compressor, means for detecting from signals from the sensing means at the individual positions flow variations above a predetermined limit of variation, means for injecting gas at a higher pressure than that prevailing at said station and generally in the direction of flow, means for actuating said injection means in response to the sensing of said variations at a series of said positions in circumferential sequence thereby to act against a flow disturbance indicated by said variations.
- 19. Apparatus for controlling gas flow in compressor comprising sensing means for sensing variations in flow at a series of circumferentially spaced positions at a chosen axial station in a direction of main flow through the compressor, means for tapping higher-pressure gas from a region downstream of said chosen station, means for injecting said higher-pressure gas into the compressor generally in said direction of flow, to act against a flow disturbance indicated by said variations, and control means for controlling said injection, the sensing means actuating said injection through said control means in a circumferentially selective manner dependent upon the circumferential origins of said variations.
Specification