An Efficient Method of Non-Gray Analysis for Studying Raditive Heat Transfer in Furnaces with Comparable Accuracy to Line-by-Line Analysis (Proposal of Method and Examination in Non-Isothermal Field)

A new efficient and accurate calculation method of non-gray analysis is proposed. The style for treating a narrow band is succeeded from our previous paper written for isotherm fields. So, the weight distribution to elemental gray gases is expressed in quadratic progression. For extending the method into non-isothermal fields, we have to decide the absorption coefficient of each elemental gray gas absorbing the radiative energy emitted from the same elemental gray gas of different temperature. In this paper, we search a proper correspondence model for absorption coefficient and incorporate it into the method proposed in our previous paper. Comparison to line-by-line analysis about the growth curve of radiative intensity on the three typical optical paths in a large-scale furnace indicate that relative error ratio in total radiative intensity is less than 2% when arriving at the furnace wall. Even assuming extremely unrealistic temperature distribution, relative error ratio is less than 3%, and this result indicates that the proposed method is valid and useful for the numerical simulation of large-scale furnaces taking radiative heat transfer into consideration.