Optical Imaging Simulation Of High Temperature Participating Medium Surface Based On Natural Element Method

The surface imaging of high temperature participating media is always an important research topic in the field of combustion and energy power. However, the imaging method can only be imaged at a certain angle. A light field camera can capture and record multi-angle optical intensity information from an exposure.The problem of radiative transfer is solved by Natural Element Method(NEM) in this paper. Then the radiation intensity of the model surface is used to simulate the optical field imaging. The radiation intensity of the homogeneous temperature field and the non uniform temperature field of the black cold wall boundary-condition of the isotropic scattering and anisotropic scattering of cylinder model is solved.The radiation intensity of the medium in the cylinder and on the boundary is obtained.The radiative intension on fixed direction of the cylinder is analyzed while the result is compared with multi-flux method(MFM), Backward Monte Carlo Method(BMC) and DRESOR method. The calculating error of NEM is analyzed to reverse BMC results as the standard. It can be concluded that the NEM has a high accuracy in solving the radiative transfer equation.In this paper, the cylinder flame model of homogeneous temperature field isotropic, anisotropic scatter and the magic flame model of non-uniform temperature field isotropic scattering are established. The imaging principle of the light field camera is used to collect the radiation intensity information of the high temperature participating medium, and the integral imaging is carried out then. The effect of spatial resolution of 30×30, 60×60 and 90×90 on spatial imaging results is analyzed.High resolution imaging is more bright, clearer and smooth, whilethe dividing line between different temperatures is also more clear and smooth.The effect of different angular resolution on the imaging results is studied.There is not much different of the integral energy imaging between 10×10 and 20×20 angle direction resolution. However, the smaller angle the camera can distinguish, the more significance for the following flame temperature reconstruction in this thesis.