Active clearance control system for a turbomachine
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsRichard P. Johnston, Malcolm H. Knapp, Charles E. Coulson
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Abstract
An axial compressor is provided with a cooling air manifold surrounding a portion of the shroud, and means for bleeding air from the compressor to the manifold for selectively flowing it in a modulating manner axially along the outer side of the stator/shroud to cool and shrink it during steady-state operating conditions so as to obtain minimum shroud/rotor clearance conditions. Provision is also made to selectively divert the flow of cooling air from the manifold during transient periods of operation so as to alter the thermal growth or shrink rate of the stator/shroud and result in adequate clearance with the compressor rotor.
Claims17
An improved clearance control system for a turbomachine including a compressor of the type having a plurality of rotor stages surrounded in close radial relationship by a stator structure, wherein the improvement comprises:
- (a) means for introducing the flow of cooling air along an axial path at the outer surface of said stator structure to inhibit thermal growth thereof, said flow-introducing means including means for bleeding motive fluid from said compressor;
- and
- (b) means for selectively diverting the flow of cooling air from said axial path during predetermined conditions of turbomachine operation, said flow-diverting means comprising an air exit duct which fluidly communicates with said flow-introducing means.
A clearance control system for an axial compressor having a plurality of axially spaced compressor stages surrounded by a closely spaced casing comprising:
- means for selectively causing the flow of cooling air axially along the outer surface of the casing to control the temperature and size thereof;
- and
- means for selectively diverting the axial flow of cooling air from the outer surface of the casing wherein said flow-diverting means comprises a diverting duct and a valve for controlling the flow of cooling air therein.
A clearance control system for an axial compressor having a plurality of axially spaced compressor stages surrounded by a closely spaced casing comprising:
- means for selectively causing the flow of cooling air axially along the outer surface of the casing to control the temperature and size thereof within said flow-causing means includes a cooling air manifold extending axially along said plurality of axially spaced compressor stages and having a flow entrance port and a flow discharge port;
- and
- means for selectively diverting the axial flow of cooling air from the outer surface of the casing wherein said flow-diverting means comprises a diverting duct which fluidly communicates with said flow entrance port.
Dependencies are inferred from the claim text.