Study On Temperature And Soot Field For Diesel Spray Combustion In Constant Volume Bomb Based On Two-Color

In the face of environmental pollution and shortage of fossil resources,in order to improve the utilization efficiency of diesel fuel and reduce exhaust emissions,it is necessary to conduct in-depth research on the in-cylinder combustion process and the mechanism of pollutant generation.Therefore,the combustion temperature in the combustion process of the diesel engine cylinder,the study of soot concentration is particularly important.In this paper,the constant-capacity combustion bomb experimental platform is used to simulate the working condition of the high-power density diesel engine cylinder.The backlight spray method and the pen-shot method are used to record the diesel spray evaporation and combustion process respectively.The variation of the diesel spray liquid phase penetration distance and the combustion flame lift length is explored.The effect of high charge temperature conditions on diesel spray evaporation and combustion processes.It is found that the liquid crystal penetration distance increases with the decrease of the gas density.The flame lift length decreases with the increase of the gas density and the ambient temperature.When the gas density increases,the flame diffusion speed decreases,and the time to reach the temperature peak is delayed.Based on the two-color method of temperature measurement,the imaging system was calibrated by using the black body furnace device,and the linear relationship between the image intensity value and the absolute radiation intensity was obtained,and the accuracy was verified.The spray burned image was processed by MATLAB software to obtain the flame boundary.The numerical simulation method was used to solve the flame field and the soot KL factor cloud map.The relationship between the combustion situation in the cylinder and the altitude is analyzed.It is found that the average temperature of the flame region becomes larger with the increase of the inlet density,the ambient temperature and the oxygen concentration,wherein the ambient temperature has a greater influence on the average temperature of the flame region;In the quasi-steady state,the average temperature of the flame region remains basically unchanged;during the spray combustion process,the flame head gradually develops into a high temperature region,and the local equivalence ratio at the boundary surface is low,and the temperature is higher than the central anoxic region;the flame and the combustible In the concentrated mixing zone of the gas,the soot KL factor is large,and a large amount of soot is generated.Comparing the calculation results of temperature field under different channels of R,G and B,it provides a reference for the measurement of combustion temperature in diesel engine.Through the measurement of the temperature field and the soot field in the flame region,the instantaneous flame combustion condition in the cylinder can be effectively obtained,which is beneficial to further the in-cylinder combustion process.