Uncertainty Evaluation in Aerothermal Test Data Due to Wind Tunnel Freestream
Shock wind tunnel is an important means to develop aerothermal prediction,and the accurate prediction of aerothermal data is of great significance to reduce the design margin of hypersonic vehicle thermal protection system and increase the payload and range of the vehicle.Therefore,it is necessary to study the uncertainty of aerothermal test data in shock wind tunnel.The uncertainty of heat flux caused by repeated operation of the shock wind tunnel is studied.Firstly,Monte Carlo method is used to analyze the measured data of the shock wind tunnel for 58 repeated runs,and the uncertainty of the random distribution of wind tunnel incoming flow parameters is obtained.The results show that the relative uncertainty of the incoming flow velocity is less than 1.02%.The relative uncertainty of incoming flow pressure is 3.54%.Then,four uncertain input variables,namely incoming flow temperature,incoming flow density,incoming flow velocity and wall surface temperature,are selected,and samples are generated by Latin hypercube sampling method.The wall heat flux data of the blunt-cone model is obtained by aerothermal numerical calculation.The uncertainty quantization and sensitivity analysis are carried out by non-embedded polynomial chaotic method.The results show that the uncertainty of heat flux caused by repeated operation of wind tunnel is about 4%～5%at the head and most areas of the blunt-cone.The results of sensitivity analysis show that the wall heat flux is most sensitive to the incoming flow velocity.Therefore,if the uncertainty of heat flux data needs to be reduced,it is necessary to reduce the uncertainty of flow velocity in the wind tunnel,which needs to control the shock Mach number of the shock tube in a smaller deviation range to achieve.
万方数据
维普
