Insulation of commercial aircraft with an air stream barrier along fuselage

Modern commercial airplanes cruise at a high altitude where it is extremely cold. To withstand the cold atmosphere, the airplaneʹs inner skin is covered by a layer of fiberglass insulation. However, this porous insulation material can entrap a large quantity of moisture after just a few months of an airplaneʹs operation, resulting in weight increase, insulation degradation and various corrosions. This paper proposes to insulate an aircraft by an air stream barrier running through an annular channel along the cross section of the fuselage. Hot air is supplied to the channel entry at the lower lobe of the aircraft to heat the aircraft before it is finally delivered into the passenger cabin. As both channel surfaces are neither in uniform temperature nor uniform heat flux, the existent correlation formulas cannot be applied to fulfill the insulation design. This investigation has applied a computational fluid dynamics (CFD) program to model a two-dimensional aircraft section insulated by such an air channel. A partial aircraft cabin mockup is constructed and put to a psychrometric chamber that is conditioned to −19 °C for experimental test. The results reveal the air channel is effective to insulate an airplane. The highly asymmetric temperature profiles across the channel also lead to asymmetric velocity profiles. In the near-window region of the passenger cabin, temperature is much elevated due to the channel, and thus cold sidewall and draft that have been repetitiously experienced by passengers seated near windows can be much alleviated.