Thermal protection for the flight data recorder
Flight data recorder is a kind of instrument that stores the flight conditions of the aircraft, commonly known as the "black box", the airborne flight data recorder needs to have the thermal protection ability of resisting high temperature fire and medium temperature baking. The flight parameters recorder can withstand full enveloping flame ablation (temperature 900 ℃-1100 ℃, heat flux greater than 158 kW/m2) for at least 1 hour, and the chip box data can be read out; 2) The flight data recorder should be kept at 260 ℃ for at least 10 hours, and the data of the chip box can be read out. The flight data recorder uses a combination of heat insulation and heat storage thermal protection structure: namely, the use of heat insulation material to reduce thermal conductivity; At the same time, phase change heat storage materials are used to absorb heat conduction into the shell and reduce the temperature of the chip box inside the flight data recorder. Because the total weight and volume of flight parameter recorder are strictly limited, the selection of suitable heat insulation material and heat storage material is the key to solve the thermal protection of flight parameter recorder.
The thermal protection device of the flight data recorder includes a thermal reservoir and a thermal insulation layer from inside to outside. The central part of the thermal reservoir is provided with a groove for inlaying a chip box. An inner shell is arranged between the heat reservoir layer and the heat insulation layer; The heat insulation layer is provided with an outer shell; The heat storage layer, the inner shell, the heat insulation layer and the outer shell are provided with an opening for drawing out the chip box power line, and the gap between the opening and the power line is filled with heat insulation material.
The heat insulation layer is composed of Mink material and multiple layers of heat insulation material. The reflective layer is any one of molybdenum foil, gold foil, copper foil, aluminum foil and stainless-steel foil, and the interlayer is any one of glass fiber paper, high-silicon oxygen fiber cloth, braided stone quartz cloth and boron nitride fiber paper.
The reflective layer of the thermal insulation material is made of molybdenum foil and the spacer layer is made of high silicon oxygen cloth spacer layer. The maximum service temperature of the multi-layer thermal insulation material formed by the spacer layer of molybdenum foil and high silicon oxygen cloth is 1125℃, which meets the application requirements of the outer surface temperature of the flight data recorder. Molybdenum is a high temperature resistant metal, so molybdenum foil is very suitable for use as a layer of heat insulation material. Our company can produce molybdenum foil which is completely suitable for reflective layer according to customer's requirements.
Insulating layer by layer outside introversion, in turn, as the first Ming grams of material layer and multilayer insulation layer, the second Ming grams of material, multilayer insulation layer with one side has openings for derivation of chip box of the power cord, opening thermal resistance is low, a large amount of heat will pass the location in chip box, the heat insulation effect of chip box will sell at a discount greatly, therefore, The insulation material filled in the gap between the opening and the power line is Mink material, that is, the gap between the opening and the power line is filled with Mink material.
