초록 ▼

A cooling system is provided for cooling a turbine of a gas turbine engine. The system has first and second flow paths for guiding cooling air received from the compressor of the engine. The routes of both flow paths bypass the combustor of the engine. The system also has a preswirler for receiving

A cooling system is provided for cooling a turbine of a gas turbine engine. The system has first and second flow paths for guiding cooling air received from the compressor of the engine. The routes of both flow paths bypass the combustor of the engine. The system also has a preswirler for receiving the cooling air at the ends of the two flow paths, swirling the cooling air tangentially to the engine axis, and delivering the swirled cooling air to a rotor of the turbine. The first flow path is routed through a heat exchanger which cools the cooling air guided by the first flow path relative to the cooling air guided by the second flow path.

대표청구항 ▼

1. A cooling system for cooling a turbine of a gas turbine engine, the system comprising: a first flow path and a second flow path that guide cooling air received from a core flow of a compressor of the engine, the start of both flow paths being at the core flow and the routes of both flow paths byp

1. A cooling system for cooling a turbine of a gas turbine engine, the system comprising: a first flow path and a second flow path that guide cooling air received from a core flow of a compressor of the engine, the start of both flow paths being at the core flow and the routes of both flow paths bypassing a combustor of the engine, the combustor comprising a combustion chamber having a wall, a compressor exit downstream of the compressor and upstream of the combustor, the first flow path flowing radially outwardly from the compressor exit, the second flow path at least partially defined by the combustion chamber wall; anda preswirler including a plurality of interconnected walls that define a receiving chamber that receives the cooling air through a first inlet and a second inlet at the ends of the first flow path and the second flow path, respectively, the preswirler swirling the cooling air tangentially to an engine axis, and delivering the swirled cooling air to a rotor of the turbine, whereinthe first flow path is routed through a heat exchanger which cools the cooling air guided by the first flow path relative to the cooling air guided by the second flow path, whereinbetween the heat exchanger and the preswirler the first flow path is routed through nozzle guide vanes of the turbine,the receiving chamber includes flow-metering outlet nozzles through which flow exits from the receiving chamber, the outlet nozzles having a flow area that determines the volume flow rate of cooling air delivered from the receiving chamber to the turbine rotor,the rotor is defined by a set of interconnected walls that are different from the plurality of interconnected walls of the receiving chamber, andwhen the flow is obstructed in either the first flow path or the second flow path, the non-obstructed flow path increases the flow of cooling air to the receiving chamber in order to compensate for the obstructed flow path and maintain the volume flow rate of cooling air delivered to the receiving chamber. 2. The cooling system according to claim 1, wherein the turbine nozzle guide vanes are upstream of the rotor. 3. The cooling system according to claim 1, wherein the nozzle guide vanes have respective internal cavities which receive, in use, a flow of further cooling air; and each vane further has one or more transfer passages which form the route of the first flow path through the vane, the or each passage traversing the respective internal cavity so that the cooling air which flows along the first flow path through the or each passage reduces the temperature of the further cooling air received by the internal cavity. 4. The cooling system according to claim 3, wherein the or each transfer passage has one or more bleed holes which allow a portion of the cooling air guided by the first flow path to be bled into the flow of further cooling air. 5. The cooling system according to claim 1, wherein the preswirler includes the receiving chamber which receives the cooling air of both flow paths, the chamber being arranged so that the cooling air from the second flow path is swirled in the chamber to reduce its static pressure and thereby educe the cooling air from the first flow path into the chamber. 6. A cooling system for cooling a turbine of a gas turbine engine, the system comprising: a first flow path and a second flow path that guide cooling air received from a core flow of a compressor of the engine, the start of both flow paths being at the core flow and the routes of both flow paths bypassing a combustor of the engine, the combustor comprising a combustion chamber having a wall, a compressor exit downstream of the compressor and upstream of the combustor, the first flow path flowing radially outwardly from the compressor exit, the second flow path at least partially defined by the combustion chamber wall; anda preswirler that receives the cooling air through a first inlet and a second inlet at the ends of the first flow path and the second flow path, respectively, swirling the cooling air tangentially to an engine axis, and delivering the swirled cooling air to a rotor of the turbine, whereinthe first flow path is routed through a heat exchanger which cools the cooling air guided by the first flow path relative to the cooling air guided by the second flow path,the preswirler includes a plurality of interconnected walls that define a receiving chamber which receives the cooling air of the first flow path and the second flow path, the chamber being arranged so that the cooling air from the second flow path is swirled in the chamber to reduce its static pressure and thereby educe the cooling air from the first flow path into the chamber,the receiving chamber includes flow-metering outlet nozzles through which flow exits from the receiving chamber, the outlet nozzles having a flow area that determines the volume flow rate of cooling air delivered from the receiving chamber to the turbine rotor,the rotor is defined by a set of interconnected walls that are different from the plurality of interconnected walls of the receiving chamber, andwhen the flow is obstructed in either the first flow path or the second flow path, the non-obstructed flow path increases the flow of cooling air to the receiving chamber in order to compensate for the obstructed flow path and maintain the volume flow rate of cooling air delivered to the receiving chamber. 7. The cooling system according to claim 1, wherein: the receiving chamber includes a first receiving chamber and a second receiving chamber; andthe first receiving chamber receives the cooling air of the first flow path, the second receiving chamber receives the cooling air of the second flow path, and the outlet nozzles include at least a first outlet nozzle for the first receiving chamber and at least a second outlet nozzle for the second receiving chamber, the outlet nozzles delivering the cooling air to the rotor. 8. The cooling system according to claim 5, wherein the receiving chamber is an annular passage coaxial with the engine axis. 9. The cooling system according to claim 1, wherein the engine is a turbofan engine, and the cooling air guided by the first flow path is cooled in the heat exchanger by bypass air received from the fan of the engine. 10. The cooling system according to claim 6, wherein the engine is a turbofan engine, and the cooling air guided by the first flow path is cooled in the heat exchanger by bypass air received from the fan of the engine. 11. The cooling system according to claim 1, wherein the amount of cooling air cooled by the heat exchanger relative to the total amount of cooling air guided by the first and second flow paths is controllable. 12. The cooling system according to claim 6, wherein the amount of cooling air cooled by the heat exchanger relative to the total amount of cooling air guided by the first and second flow paths is controllable. 13. A gas turbine engine having the cooling system of claim 1. 14. A gas turbine engine having the cooling system of claim 6.