GAS TURBINE ENGINE TWO DEGREE OF FREEDOM VARIABLE BLEED VALVE FOR ICE EXTRACTION

摘要

A gas turbine engine variable bleed apparatus (48) includes a variable bleed valve door (50) disposed in a bleed inlet (47) in a transition duct (29), rotatable about two or more separate pivot points (160), operable to open and close an aft bleed slot (170) extending outwardly from transition duct (29), and operable to open and close a forward bleed slot (180) extending inwardly into transition duct (29). Door (50) is operable to transition between a first position with aft bleed slot (170) open and forward bleed slot (180) closed to a second position with aft bleed slot (170) closed and forward bleed slot (180) open without fully closing door (50). Door (50) is rotatable about an axis (160) translatable between the two or more separate pivot points. Transition duct (29) having a transition duct conical angle (Al) at least about 10 degrees greater than a booster conical angle (A2) of a booster outer shroud (222) upstream of transition duct (29).