Research On Temperature Measurement Method Of Toluene Two-color Planar Laser Induced Fluosrescence

Along with the rapid development of modern aircraft,in the process of vehicle speed,the surface of the flow field and the flying plane surface friction between the reaction will make the flow field on the surface of the aircraft changes,cause,the transition of flow field and the happening of the transition will bring a series of influence,so the measurement of transition in recent years is the focus of research aircraft surface flow field changes.One of the influences caused by transition is the generation of aerodynamic heat.Due to the change of flow field temperature caused by transition,transition is measured according to the temperature.Most of the traditional measurement methods are ground simulation experiments in wind tunnels.According to the relevant conclusions obtained from the simulation experiments,the temperature measurement method is static and has certain limitations.Therefore,this paper proposes a method based on plane laser induced fluorescence(PLIF)to dynamically measure the temperature distribution in ground experiments.Using PLIF technology,appropriate tracers should be selected to characterize the characteristic information of the flow field according to the fluorescence characteristics of the tracer.Toluene was selected as the tracer in this paper.Toluene is a highly sensitive temperature and its fluorescence characteristics meet the temperature variation range of ground experiments.Therefore,toluene was selected as the tracer.In this paper,based on the expression of toluene fluorescence intensity,a toluene two-color plane laser induced fluorescence temperature measurement model is proposed.Then the fluorescence spectra of toluene under different conditions were measured and analyzed according to the fluorescence spectra characteristics of toluene.The band of toluene two-color PLIF was selected to measure temperature,the relationship between temperature and intensity was determined according to the fluorescence spectrum of different temperatures,and the appropriate filter was selected.The empirical formula of theoretical temperature measurement was given according to the data.According to the empirical formula,the flow field test is verified experimentally.The experiments include calibration tests and measurement of the diffusion process of toluene gas in heat flux through the heating device on the surface of the plate.The results of calibration experiments show the same variation trend as the empirical formula,but there are some numerical differences.The measurement of diffusion experiment gives the difference between different working conditions,and the measured distinguishable temperature changes with the working conditions are about 80 K.Both experiments show the feasibility of the experimental method,but there are some experimental errors.Although the feasibility of the experiment scheme is illustrated,but in the subsequent process experiment scheme can still have a lot of improvement,this paper,based on the scheme and the results of the experiment,according to the actual situation the optimizing scheme of experiment and improvement measures,and at the same time improve fluorescence spectral characteristics of toluene,providing theoretical basis for the follow-up experiment,makes the toluene can be used as a tracer to ground experimental temperature field measurement,and then study the transition.