Patent ID: 9617916
Date: 2017-04-11
CPC Classifications: F01D,F02C

Claim:
1. A gas turbine engine having an annular gas path between a radially outer wall and a radially inner wall, leading successively across at least one compressor stage, a combustor section, and at least one turbine stage, the gas turbine engine comprising: a bleed air aperture in the radially outer wall upstream from the combustor, the bleed air aperture drawing pressurized bleed air from the at least one compressor stage which is carried along a bleed air path, at least a portion of the pressurized bleed air being used for pressurizing an aircraft cabin; a bearing cavity formed within the radially inner wall, having at least one bearing therein rotatably supporting at least one shaft of the gas turbine engine, at least two bearing seals enclosing the at least one bearing in the bearing cavity and separating the bearing cavity from at least one buffer air entry point, and at least one scavenge passage inlet in the bearing cavity; an oil supply system including at least one oil path leading to the at least one bearing; a buffer air supply system including at least one buffer air path leading to the at least one buffer air entry point; and a baffle extending across the at least one buffer air path and partitioning said buffer air path into first and second portions, the first portion being upstream of the second portion relative to normal flow through the at least one buffer air path during normal flow conditions of the gas turbine engine, the first portion communicating with the at least one buffer air entry point and a secondary path flowing to a portion of the gas path upstream of the bleed air aperture relative to normal flow through the gas path during normal flow conditions of the gas turbine engine, the secondary path being downstream of the baffle relative to the normal flow through the gas path during normal flow conditions of the gas turbine engine, a first flow restrictor being disposed within the secondary path, the second portion being exposed to one of the at least two bearing seals and communicating with a deviation path flowing to a deviation outlet separate from the portion of the gas path upstream of the bleed air aperture, the deviation path having a second flow restrictor sized to maintain flow from the first portion toward the second portion across the baffle and from the second portion toward the bearing cavity across the bearing seal during normal flow conditions of the gas turbine engine, said baffle guiding fluid within the second portion through the deviation path, upon flow reversal.