Research On Fluorescence Spectral Characteristics Of RP-3 Kerosene And PLIF Temperature Measurement

With the rapid development of aero-engine industry and the aggravation of air pollution,high efficiency and low pollution fuel combustion has become increasingly important.Kerosene is an important fuel in aero-engine combustion chamber.The analysis of its physicochemical properties and flow field structure has become the focus of research.In particular,the research on the basic theory of kerosene spectrum is of great significance for the analysis of the composition and thermal effect of kerosene.However,at present,the research in this field in China is still in the development stage and lacks a large number of basic data support.In view of the situation,a non-contact flow field diagnosis technology--laser-induced Fluorescence(LIF)was used to measure the Fluorescence spectrum of kerosene and detect the temperature distribution of kerosene flow field.In this paper,domestic RP-3 aviation kerosene was selected as the tracer of LIF technology.Firstly,the energy level transition principle was analyzed,and the oxygen quenching effect formula of kerosene was deduced.The effects of pressure and temperature on fluorescence signal intensity are summarized.Through the analysis of kerosene fluorescence theory formula,the possibility of temperature measurement by two-color method is put forward,and the formula is simplified and deduced.The kerosene fluorescence spectra under different pressure,gas environment and temperature conditions were measured,and the characteristics of the fluorescence spectra were analyzed,so the fluorescence bands suitable for the two-color method were selected.The relationship between the fluorescence intensity of kerosene in different bands and the temperature in Atmospheric pressure and nitrogen environment was obtained by using a camera equipped with different filters.The calibration experiment was carried out,and empirical formula of two-color temperature measurement is obtained by fitting.The local temperature of kerosene flow field was measured in atmospheric nitrogen environment,and the accuracy of temperature measurement by the two-color method was verified experimentally.Through PLIF imaging of kerosene flow field at different airflow velocities,and inversion of PLIF image.Based on the expression obtained,the temperature distribution image of the flow field is obtained.The thermocouple was used to directly detect the temperature at the root of the flow field.The experiment showed that the temperature of the jet field gradually increased with the increase of the velocity of the inner ring airflow,and the maximum temperature difference at the same position reached 40℃.The measurement errors under the different working conditions were analyzed,and the final temperature measurement errors were 13.2%.The experimental results show that although the research in this paper has not been directly applied to aero-engine,the study on kerosene fluorescence spectrum provides a theoretical basis for subsequent experiments,and verifies the feasibility of temperature measurement scheme,and provides a method for temperature measurement in real aeroengine environment.