Abstract: A liner is provided for an air flow passage of a gas turbine engine. The liner comprises an acoustic attenuation layer which forms an air-washed surface of the flow passage, and a heat exchanger layer which extends as a backing to the acoustic attenuation layer. The heat exchanger layer is configured to carry a heated fluid flow and to transport heat from the fluid flow to the acoustic attenuation layer from where the heat is transferred to air flowing through the air flow passage.

Abstract: A heat exchanger is provided for warming fuel prior to introduction of the fuel to an engine, the heat exchanger including: a fuel inlet and a fuel outlet; a heat exchange matrix having heat transfer components past which the fuel flows between said inlet and said outlet and which are arranged to be heated; and swirl inducing means arranged between said inlet and said matrix arranged to cause fuel from said inlet to swirl prior to entering said matrix. By causing the fuel to swirl prior to entering the heat exchange matrix, entrained ice in the fuel can be caused to concentrate at an outer region of the heat exchanger thereby allowing fuel to continue to flow through the heat exchanger to the engine even when ice is present in the fuel.

Abstract: A liner is provided for an air flow passage of a gas turbine engine. The liner comprises an acoustic attenuation layer which forms an air-washed surface of the flow passage, and a heat exchanger layer which extends as a backing to the acoustic attenuation layer. The heat exchanger layer is configured to carry a heated fluid flow and to transport heat from the fluid flow to the acoustic attenuation layer from where the heat is transferred to air flowing through the air flow passage.