Experiment and simulation on aircraft thermal protection and utilization integrated system

When an aircraft flies at a high Mach number for a long time，the airflow in the boundary layer of the aircraft wall will generate aerodynamic heat because of strong friction，which can cause the temperature near the wall to rise or even exceed the temperature resistance limit of the material to the disadvantage of the aircraft.A lattice truss structure based on active cooling was designed to reduce the weight of the aircraft while achieving thermal protection effectively.At the same time，a semiconductor thermoelectric conversion device was added to the structure to convert the generated aerodynamic heat into electrical energy，which could be used to supply power for small electrical equipment of aircraft.The proposed integrated system of thermal protection and utilization was studied through experiment and the results showed that the power of thermoelectric conversion was much larger than the pump power consumption of the active cooling system，which can realize the self-driving of the active cooling system.Furthermore，the thermal protection performance of the actively cooled lattice truss structure was optimized by numerical simulation method，and the heat transfer effect was enhanced by adding the inner tube protrusions and the spiral twist.The results showed that the coupling of the inner tube protrusions and the twisted band can significantly improve the thermal protection performance of the system.At the flow velocity of 0.1 m/s，the maximum temperature of the outer and inner panels decreased by 14.4% and 17.8%，respectively，when water was used as working fluid，and 15.0% and 34.5%，respectively，when kerosene was used as working fluid.