Simultaneous Reconstruction of the Temperature and Inhomogeneous Radiative Properties of Soot in Atmospheric and Pressurized Ethylene/Air Flames

Abstract

ABSTRACT An inverse method is proposed to retrieve soot temperature and radiative properties in co-flow laminar diffusion ethylene/air flames. The proposed inverse method is first verified as capable of the simultaneous reconstruction of soot temperature and inhomogeneous radiative properties with and without scattering. Thereafter, the soot temperature, absorption and scattering coefficients in atmospheric ethylene/air flames is experimentally inverted from the radiative intensity taken by a hyper-spectral imaging device by means of the inverse method. From the results, it is found that neglecting scattering has an insignificant influence on the retrieved flame radiative properties, due to the weak scattering ability of soot in the atmospheric flames. Furthermore, the simultaneous reconstruction of the soot temperature and inhomogeneous radiative properties is also numerically conducted in the pressurized flames, where scattering has comparable strengths with absorption. In general, neglecting scattering in pressurized flames leads to significant underestimation of the retrieved temperature and obvious deviation of the retrieved absorption coefficients. It follows that the effect of scattering from high levels of soot in these pressurized flames is significant and should generally be considered in the reconstruction (measurement) of soot properties.