The SLW-1 model for efficient prediction of radiative transfer in high temperature gases

A reduced SLW model consisting of a single gray gas and a clear gas is developed as an efficient spectral method for modeling radiation transfer in high temperature gases. It is shown that the SLW-1 model is not simply a reduction of the SLW method to the case of a single gray gas. Good accuracy can be achieved by the optimal choice of the model's gray gas absorption coefficient and its weight by application of the Absorption-Line Blackbody Distribution Function (ALBDF), which is calculated with a high-resolution spectral database. Different approaches to the construction of the SLW-1 model are shown. The SLW-1 model absorption spectrum still has the line structure corresponding to the real gas absorption spectrum, which is maintained with fixed spectral intervals in non-uniform medium with the help of the reference approach. The validation of the SLW-1 model is performed by comparison with (i) benchmark solutions obtained by the line-by-line method and (ii) the SLW method with a large number of gray gases. Formulation of the SLW-1 method is also shown with the Two-Flux method and P-1 differential approximation.

Research highlights► A minimal SLW model has been formulated, using one clear gas and one gray gas. ► The SLW-1 model offers considerable simplicity and computational economy. ► Model predictions of local radiative flux are within a few percent of benchmarks. ► The model can be extended to handle non-isothermal and non-homogeneous gases. ► The SLW-1 model is demonstrated adaptable to approximate RTE solution methods.