초록 ▼

A bleed air buffer seal arrangement is provided for improved buffer sealing of oil sump seals in a gas turbine engine. In a multiple spool gas turbine engine, bleed air for buffer sealing is obtained through an annular bleed slot or annular array of bleed ports formed in the impeller shroud of a hig

A bleed air buffer seal arrangement is provided for improved buffer sealing of oil sump seals in a gas turbine engine. In a multiple spool gas turbine engine, bleed air for buffer sealing is obtained through an annular bleed slot or annular array of bleed ports formed in the impeller shroud of a high pressure centrifugal impeller at a location spaced aft or downstream from the leading edge thereof. Bleed air from this location exhibits significant pressure at low engine power conditions to provide satisfactory buffer sealing, without subjecting sump seals to excess pressure or temperature at high engine power conditions.

대표청구항 ▼

In a gas turbine engine having a main gas flow path and separately spooled first and second compressor stages for series compression of air flowing through said main gas flow path, bearing means for rotatably supporting rotating components of the engine, sump means including oil flow passages for ci

In a gas turbine engine having a main gas flow path and separately spooled first and second compressor stages for series compression of air flowing through said main gas flow path, bearing means for rotatably supporting rotating components of the engine, sump means including oil flow passages for circulating lubricant to said bearing means, and sump seals for preventing lubricant leakage from said oil flow passages, a bleed air buffer seal arrangement comprising: housing means defining a buffer chamber in flow communication with said main gas flow path via a bleed port formed at a location spaced aft from an upstream end of said second compressor stage to provide said buffer chamber with a supply of bleed air which has been compressed by said first compressor stage and partially compressed by said second compressor stage; and said housing means further defining duct means for communicating said bleed air from said buffer chamber to one side of each of said sump seals whereby said bleed air provides a pneumatic buffer to prevent lubricant leakage past said sump seals; and wherein said second compressor stage comprises a centrifugal compressor having a centrifugal impeller rotatably supported within an impeller shroud, said bleed port being formed in said impeller shroud.