| 摘要 |
A tangential on board injector with auxiliary supply of further cooled compressed air, from an external heat exchanger or air cooled bearing galler y for example, serves to reduce the volume of cooling air directed tangentiall y toward a cooled rotor of a gas turbine engine. The tangential on board injector has an array of injector blades (21) between two injector walls defining circumferential main flow nozzles for directing a main compressed a ir flow tangentially. Each blade has an interior chamber (25) in flow communication with a source of auxiliary compressed air with at least one bo re (27, 28) extending between the chamber and an exterior surface of the blade. The bores eject further cooled air from the heat exchanger and merge with th e primary compressed air flowing through the injector nozzles. The bores (27, 28) may also produce a cooling film of air that reduces drag over the inject or blades. Advantages of the further cooling bores (27, 28) include: reduction in injector air temperature and corresponding reduction in cooling air flow requirements; added control over injector flow volume and temperature to fin e tune the delivery of cooling air to the rotor blades; improved cooling air control results in extended durability and service life of air cooled rotor blades; and the ejection of air near the trailing edge of the injector blade s results in less drag and air pressure requirements.
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