GAS TURBINE ENGINE VARIABLE BLEED VALVE FOR ICE EXTRACTION

摘要

A variable bleed valve (49) includes a variable bleed valve door (50) disposed in a bleed inlet (47) in transition duct (29) and rotatable about an axis (160) at or near a forward end (53) of door (50). Valve (49) is operable to open and close a bleed slot (170) open to a booster bleed flowpath (46) located outwardly of transition duct (29) and having an airflow restrictor (88). Airflow restrictor (88) may be variable such as a flapper valve (92). Booster bleed flowpath (46) may pass through a bifurcated bleed duct (64) including an inner passage (60) radially bound by spaced apart inner and middle bleed walls (70, 72) and an outer passage (62) radially bound by middle bleed wall (72) and an outer bleed wall (74). Airflow restrictor (88) may include an outlet area (AO) smaller than an inlet area (AI) of inner passage (60). Door (50) seals against middle bleed wall (72) to open inner passage (60) and against outer bleed wall (74) to open both passages (60, 62).