本文提出等效透射能量比的概念,在此基础上建立反演高温均一粒子系光学常数(复折射率)的理论模型,该模型基于完整的辐射传递方程,采用Mie理论结合K—K关系式反演高温粒子的复折射率。以燃烧火焰中常见的煤灰粒子为例,通过将已知文献中煤灰粒子复折射率数据作为“真实”数据,采用MC方法进行正问题计算所得的等效透射比作为“实验测量值”,然后利用本文模型进行反演,得到较好的反演结果,充分说明了本文所建反演模型的可行性,同时分析了测量误差对实验结果的影响,对于反演高温粒子复折射率的实验研究具有一定的理论指导意义。
Based on the concept of equivalent spectral transmittance ratio (ESTR), an inverse model has been developed to determine the optical constants of the high temperature particles. Combined with the Mie theory and Kramers-Kronig (K-K) relations, the complex refractive indices of the high temperature particles are retrieved with forward simulation of the complete radiative transfer equation (RTE). In order to validate the present model, the optical constants of the fly-ash particles available in the references are selected as the 'true values', and the direct simulation values of ESTR in one-dimensional (1D) slab by Monte Carlo method are regarded as the 'experimental values'. Good agreement was obtained between the retrieved optical constants and the known 'true value'. The influence of measurement error on the inverse results was also investigated. All the results show that the proposed inverse model could be used to determine the optical constants from the in-situ ESTR measurements of high temperature particles effectively, which is more important for directing the experiment of retrieving optical constants of high temperature particles in the further research.