COOLED STATIONARY BLADE OF A GAS TURBINE

摘要

A gas turbine cooling stationary blade, in which steam cooling and air cooling are used in combination to reduce an amount of cooling air, and which comprises outer and inner shrouds (1, 21), steam passages (10A, 10B, 10C, 10D, 10E) which communicate to one another, and a sealing air supply tube (2) passing through the center thereof, wherein the outer shroud (1) is provided with steam lids (3, 4) for introduction of steam (S) from a stream supply port (5), the steam (S) going through an impinge plate (8) to cool the center portion of the outer shroud (1) and passing through a serpentine passage composed of the steam passages (10A-10E) to be recovered from a steam outlet (12). A part of the steam in the passage (10A) enters a steam receiver (24) from an impinge plate (25) to cool the center portion of the inner shroud (21) to pass through the passage (10D) to be recovered from the steam outlet (12). Meanwhile, a cooling air is supplied to the vicinities of the outer and inner shrouds (1, 21) from cooling air supply ports (6, 26) to be discharged outside from the backward thereof, and a cooling air is supplied to the passage (10E) on a trailing edge side of the blade from a cooling air supply port (7) to cool a trailing edge of the blade. Air cooling is effected only on narrow portions, through which the steam hardly passes, to reduce an amount of cooling air.