Study On Surface Temperature Field And Its Similarity Of Aircraft

With the development of modern national defense science and technology and the application demand of target infrared radiation characteristics,the analysis of surface temperature field of aircraft has become the focus of research in the field of defense and military.The analysis of the surface temperature field of aircraft needs to consider the coupling effect of internal and external heat environment,such as internal multi-body coupled heat transfer,external air convection heat transfer,environmental radiation and solar radiation.At present,numerical simulation combined with ground simulation test is the most economical and reliable method to obtain the surface temperature data of aircraft.However,due to the limitation of experimental conditions,it is difficult to simulate the real flight environment.Therefore,there is an urgent need to establish the similarity criterion for the surface temperature field of aircraft based on the similarity theory,and to realize the similar transformation of the surface temperature data between the ground shrinkage model and the real aircraft.In this paper,the whole thermal environment of a certain type of airplane is taken as the research object.The external aerodynamic convection heat transfer analysis model and the whole airplane thermal network model are established to carry out the calculation of the external aerodynamic convection heat transfer and the surface temperature field of the airplane under the interaction of internal and external coupling,under different flight conditions.The influence of whether there are internal heat sources,solar radiation and atmospheric temperature on the surface temperature field of airplane in different seasons are analyzed.And the similarity criterion applicable to the surface temperature field of aircraft is studied,the main contents include:Calculation of the surface temperature field of airplane and analysis of its influencing factors.Based on the physical formation mechanism of the airplane's whole thermal environment and the basic principle and calculation method of the analysis of the surface temperature field,the external aerodynamic convection heat transfer analysis model and he whole airplane thermal network model are established,the calculation of the external aerodynamic convection heat transfer and the surface temperature field of the airplane under the interaction of internal and external coupling are finished,and the influence of whether there are internal heat sources,solar radiation and atmospheric temperature on the surface temperature field of airplane in different seasons are analyzed.Analysis of the similarity criterion of the surface temperature field of airplane.Based on the basic principle of similarity of the surface temperature field of the airplane,the basic equations of fluid mechanics and heat transfer and their boundary conditions are used to derive the flow similarity criterion and heat transfer similarity criterion,which is applicable to the surface temperature field of the airplane.Through the numerical simulation calculation of the prototype and scaling model of the simple structure,the correctness of the similarity criterion of the surface temperature field of airplane is verified.Calculation of the surface temperature field of airplane based on the similarity criterion.According to the similarity criterion of the surface temperature field of airplane,the material,size and boundary conditions of the scaling model are determined,the surface temperature field of the scaling model under different experimental conditions is calculated,the similar conversion between the temperature field data of the ground simulation experiment and the surface temperature field data of the real airplane is realized and the results are compared with the calculation results of the surface temperature field of airplane,the feasibility of ground simulation test based on the similarity criterion of the surface temperature field of airplane is analyzed.By establishing the analysis and calculation model of the surface temperature field of a certain type of airplane,the calculation of the surface temperature field and the analysis of the influence factors are completed,the similarity criterion of the surface temperature field of the airplane is established,and the similar conversion between the temperature field data of the ground simulation experiment and the surface temperature field data of the real airplane is realized,which provide effective data support for the study of infrared radiation characteristics of airplane.