Research On Reconstruction Of 2D Flame Temperature Field And Radiation Characteristic Parameters Based On Radiation Image Processing

As an important parameter of fuel combustion,flame temperature is of great significance for reflecting combustion status and improving combustion efficiency.The radiation image of the flame contains temperature and radiation characteristics information,and the reconstruction algorithm can be used to obtain the flame temperature and radiation characteristic parameters from the radiation image.This paper will conduct a reconstruction study of flame temperature field and radiation characteristic parameters based on radiation image processing,aiming to accurately measure the flame internal temperature and radiation characteristic parameters.The main research contents of the paper are as follows:First,a quantitative radiation transfer relationship is established between the boundary radiation intensity in the radiation image and the flame temperature,so as to establish the flame radiation transfer model.By simulating flame,the established radiation imaging model is verified,and it is proved that the radiation imaging model can reconstruct the temperature and radiation characteristic parameter distribution of the non-uniform flame well.And verify the feasibility of the radiation imaging model under different conditions:when considering the measurement error,the reconstruction algorithm has good anti-noise ability;when considering the presence of wall emission or scattering,the calculated boundary radiation intensity ratio does not consider the wall emission or scattering The effect is high;under the condition of changing the initial value of the iteration,the flame temperature and radiation characteristic parameters can be successfully reconstructed.Then,the reconstruction algorithm is used in the laboratory ethylene flame detection.After the digital CCD is calibrated,the digital CCD is used to perform the laminar diffusion flame of ethylene under 21%O₂-air,30%O₂-air and 40%O₂-air.Shoot and reconstruct the flame temperature and smoke black volume distribution under different oxygen concentrations.The results show that when the fuel and accompanying gas flow rates are the same,the higher the accompanying oxidant content,the lower the flame height and the higher the maximum temperature,and the peak of the soot volume fraction always appears inside the temperature peak,indicating the soot One of the contributing factors is the lack of oxidant.The TSPD-TEM probe sampling technique was used to detect the soot volume fractions at different heights of the three flame centers,which was in good agreement with the reconstruction results.Finally,using a hyperspectral instrument to photograph the laminar diffusion flame in the laboratory,high spatial resolution images containing multi-wavelength radiation intensity information can be obtained,and the effect of different wavelengths on the reconstruction of the flame temperature field and smoke black volume fraction can be studied.The results show that:when the selected wavelength is less than 580nm,the internal temperature of the reconstructed flame is low;when the selected wavelength is greater than800nm,the measurement error of the instrument increases and the reconstructed flame temperature is inaccurate;when the difference between the two wavelengths is less than36nm,the radiation intensity of the two wavelengths The similar size causes the overall temperature of the reconstruction flame to be too high;when the wavelength difference is greater than 140nm,it is easy to fail to satisfy the flame ash assumption and the reconstruction flame temperature is lower.