| 摘要 |
PROBLEM TO BE SOLVED: To switch the steam cooling system and the air cooling system by fitting a switching ring to cover a space between internal an external walls to an upstream side end portion of the internal and external walls, and selectively fitting the switch ring having an annular projection member to cover a film cooling hole and one having no annular projection member. SOLUTION: When a hybrid combustor is switched from the steam cooling system to the air cooling system, an external compressor 13 is installed in advance, after the air in a gas turbine casing 11 is extracted and cooled by a cooler 12, the cooled air is led to the external compressor 13 and boosted. It is further fed to a convection cooling passage 15 to cool inner surfaces of the combustor tail cylinder 2, and cool an inner circumferential surface of an internal wall 2a of the tail cylinder 2 by ejecting the air from a film cooling hole 17. On the other hand, in the steam cooling system, a switching ring 18a is inserted from an upper portion of the tail cylinder 2 to cover the film cooling hole 17, and the cooling steam extracted from an exhaust gas boiler 21 through a selector valve 14a is introduced into the cooling passage 15 to cool the inner surface of the tail cylinder 2.
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