Combined thermal and noise insulation for jet pipes - has metallic honeycomb covered with layer of porous refractory material in metal casing

摘要

The jet pipe of a jet engine has a jacket which insulates both heat and noise. The jacket has a metal outer surface (40) which supports a layer (50) of porous refractory material (50). The inner surface of the refractory has a lining of metal foil (60) which supports a honeycomb structure (11). The inner surface of the honeycomb is covered with a perforated metal sheet (12) so that each cell of the honeycomb communicates with the jet gases. The metal parts are made of titanius or heat resisting super alloys whilst silicon fibres are used for the refractory layer (50).