Experimental Study On Three-dimensional Internal And External Coupling Verification Of Thermal Protection Structure Of Aircraft

Near-space hypersonic aircrafts are seriously heated inside and outside,and the outside of the cabin is subjected to severe aerodynamic heat.Long-time operation of onboard power supply,computer,communication equipment,etc.in the cabin will also generate a large amount of heat.In order to meet the requirements of thermal effect prediction,calculation and analysis of equipment in-and-out coupling,it is necessary to master the influence law of aircraft on thermal effect of in-and-out coupling caused by aerodynamic heat,thermal protection structure and in-cabin instrument arrangement,so as to provide effective support for the design of thermal protection system of spacecraft and provide certain theoretical basis for localization of three-dimensional thermal effect software of in-and-out coupling.In this paper,the research group's self-developed software 3Ddesign is used to carry out numerical simulation and design relevant experimental models for ground tests and quantitative analysis.The factors affecting the internal and external coupling effect are deeply studied and some progress has been made,including the following aspects:First,aiming at the generation and transmission of heat during the operation of hypersonic aircrafts,the thermal environment of the thermal protection structure of the aircraft equipment cabin is analyzed,and the basic principles and control equations involved in the three-dimensional internal and external coupling thermal effects,as well as the basic principles and control equations of node thermal network method and radiation factor calculation method are explored.Second,in order to simulate the thermal effect of internal and external coupling in the equipment cabin,the solid model and the matching detection sensor are manufactured,and the related constraint conditions of the experimental model are established.Including simplifying the modeling of the thermal protection structure of the cabin body and the instruments in the cabin,designing the manufacturing materials and processing methods,and planning the selection of the constraint conditions such as the radiation factor of each equipment,the installation and fixing methods,the detection equipment,the tightness,etc.Finally,the heat flow provided by the quartz lamp radiation software and the thickness of the cabin shell are adjusted to simulate the different external aerodynamic heating and thermal protection structures of the equipment cabin.By changing the location of the surface module,the influence of the location of the heat source on the coupling is simulated.Through numerical simulation and quantitative analysis,it is found that the heat source in the cabin and the aerodynamic heat outside the cabin have different effects on the coupling thermal effect at different times,and the effects of internal heat source on other instruments are different with or without shielding.Therefore,the design can be carried out according to the required working temperature of different instruments to meet the stability of the working environment of instruments in the cabin.A data parameter is designed,namely the radiant heat flux power is 0.39 k W and the cabin thickness is 9mm,which can meet the working conditions required by the experimental model.According to this typical case,experimental studies on different series of quartz lamp power and simulated equipment cabin position were carried out,and the influence law of external heating heat flow and rolling angle on heat transfer of equipment cabin was obtained.