| 摘要 |
Cooling airflow is modulated by means of interacting metering apertures formed in members 42, 46 that can move in relation to each other according to changes in operating temperature. The modulation method may be applied to a gas turbine engine airfoil, having a wall (42) provided with a cooling effusion hole 40 therein for film cooling the external surface 52 of the wall 42. A member 46 attached (at one edge or at a point between two metering apertures) to the internal surface 48 of the wall 42 is provided with an aperture 44 which at least partially overlaps the cooling effusion hole 40. The airfoil wall 42 and member 46 are formed from materials having different coefficients of thermal expansion whereby over a temperature range, the aperture 44 and cooling effusion hole 40 interact to a greater or lesser extent to modulate the flow of cooling air therethrough.
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