Gas turbine outer case active ambient cooling including air exhaust into sub-ambient cavity

A gas turbine engine including an exhaust section comprising:

• an outer case defining a central longitudinal axis, and an outer case having an upstream flange and a downstream flange and an exterior surface extending circumferentially between the upstream and downstream flanges around the central longitudinal axis, the upstream and downstream flanges extending radially outward from the exterior surface of said outer case;
• a panel structure extending circumferentially around said outer case and having upstream and downstream ends affixed to said exhaust section, said panel structure is radially spaced away from said exterior surface to define a cooling channel and said exterior surface;
• an exhaust duct located within said outer case and defined between an outer duct wall and an inner duct wall, said exhaust duct defining a passage for hot exhaust gases flowing in an axially downstream direction and exiting a turbine section of said gas turbine engine;
• a rear bearing housing located radially inward from said inner duct wall;
• a strut extending from said outer case to said bearing housing;
• a shield structure surrounding said strut to shield said strut from said exhaust gases;
• an air opening formed through said outer case exterior surface in fluid communication with said cooling channel, said air opening being in fluid communication with a radial passage extending between said strut and a portion of said shield structure;
• and
• a disk cavity located adjacent a stage of said turbine section and in fluid communication with said radial passage, said disk cavity being at a pressure lower than an ambient air pressure outside of said turbine engine for effecting a flow of ambient air through said air opening into said disk cavity,
• wherein ambient air entering said air opening passes through said panel structure and into said cooling channel, and
• wherein said cooling channel extends circumferentially around said outer case, and said panel structure comprises plural panel sections with axially extending gaps defined between adjacent panel sections at spaced circumferential locations, said gaps permitting passage of ambient air into said channel.

A gas turbine engine comprising:

• an outer case defining a central longitudinal axis, and the outer case defining an surface extending circumferentially around the central longitudinal axis;
• an exhaust gas passage defined within the outer case for conducting an exhaust gas flow from a turbine section of the gas turbine engine;
• a cooling channel defined between the outer surface of said outer case and a panel structure supported on said outer case, said cooling channel having a channel inlet and a channel outlet;
• said panel structure comprises plural panel sections with axially extending gaps defined between adjacent panel sections at spaced circumferential locations, said gaps permitting passage of ambient air into said cooling channel;
• an air duct structure including an inlet end in fluid communication with said channel outlet and an outlet end in fluid communication with an area of reduced pressure relative to said air duct structure inlet end;
• and
• an exit cavity at said air duct structure outlet end, said exit cavity effecting a reduced pressure at said outlet end to draw air from said cooling channel into said air duct.