A gas turbine engine includes a lubrication system, fuel system and thermoelectric heat exchanger adapted for selective operation in response to operational states of the gas turbine engine.

A vacuum insulated blast tube includes an insulating layer of a burn resistant material such as phenolic resin formed on an interior surface of the blast tube to provide the necessary erosion and thermal insulation properties to protect the blast tube and a vacuum insulated layer formed in the walls of the blast tube itself to provide the additional thermal insulation properties to protect any non-propulsive sub-systems positioned in the void space around the blast tube. A void space in the walls of the blast tube is held under vacuum with a pressure of less than 25 Torr and a thermal conductivity Tcond_vac of less than one-third of the thermal conductivity of air Tcond_air to form the vacuum insulation layer.

A vacuum insulated blast tube includes an insulating layer of a burn resistant material such as phenolic resin formed on an interior surface of the blast tube to provide the necessary erosion and thermal insulation properties to protect the blast tube and a vacuum insulated layer formed in the walls of the blast tube itself to provide the additional thermal insulation properties to protect any non-propulsive sub-systems positioned in the void space around the blast tube. A void space in the walls of the blast tube is held under vacuum with a pressure of less than 25 Torr and a thermal conductivity Tcond_vac of less than one-third of the thermal conductivity of air Tcond_air to form the vacuum insulation layer.

A vacuum insulated blast tube includes an insulating layer of a burn resistant material such as phenolic resin formed on an interior surface of the blast tube to provide the necessary erosion and thermal insulation properties to protect the blast tube and a vacuum insulated layer formed in the walls of the blast tube itself to provide the additional thermal insulation properties to protect any non-propulsive sub-systems positioned in the void space around the blast tube. A void space in the walls of the blast tube is held under vacuum with a pressure of less than 25 Torr and a thermal conductivity Tcond_vac of less than one-third of the thermal conductivity of air Tcond_air to form the vacuum insulation layer.