Gas turbine engine with outer case ambient external cooling system

A gas turbine engine comprising:

• an outer case defining a central longitudinal axis, and an outer case surface extending circumferentially around the central longitudinal axis;
• a thermal barrier/cooling system for controlling a temperature of the outer case, the thermal barrier/cooling system including:
• an internal insulating layer supported on an inner case surface opposite the outer case surface, the internal insulating layer extending circumferentially along the inner case surface and providing a thermal resistance to radiated energy from structure located radially inwardly from the outer case;
• and
• a convective cooling channel defined by a panel structure located in radially spaced relation to the outer case surface and extending around the circumference of the outer case surface, the convective cooling channel is generally axially aligned with the internal insulating layer and forms a flow path for an ambient air flow cooling the outer case surface;
• and
• the panel structure comprises a plurality of circumferentially located panel segments joined at axially extending joints, the air flow through the cooling channel creating a pressure lower than an ambient air pressure such that any air leakage through the joints comprises leakage of ambient air into the cooling structure.

A gas turbine engine comprising:

• an outer case comprising a turbine exhaust case defining a central longitudinal axis extending in a generally horizontal direction, the exhaust case having an upstream exhaust case flange, a downstream exhaust case flange, and an outer case surface between the upstream and downstream exhaust case flanges extending circumferentially around the central longitudinal axis, the upstream and downstream exhaust case flanges extending radially outward from the outer case surface;
• a thermal barrier/cooling system for controlling a temperature of the outer case, the thermal barrier/cooling system including:
• an internal insulating layer supported on an inner case surface opposite the outer case surface and spanning axially from the upstream exhaust case flange to the downstream exhaust case flange, the internal insulating layer extending circumferentially along the inner case surface and providing a thermal resistance to radiated energy from an exhaust diffuser located radially inwardly from the outer case;
• and
• a convective cooling channel including at least a first portion defined by a panel structure located in radially spaced relation to the outer case surface and extending continuously around the circumference of the outer case surface and located within a space defined between the upstream and downstream exhaust case flanges, and the convective cooling channel is axially aligned with the internal insulating layer and forms a flow path for directing an ambient non-forced air flow in an upward direction to cool the outer case surface.