Treatment of radiative properties in combustion modelling

Övrigt konferensbidrag, 2015

The radiative properties of combustion products are important for the radiative heat transfer in furnaces. A rigorous treatment of their spectral variations is demanding in terms of computational resources and is not suitable for comprehensive combustion modelling, where more approximate models are required. There is, however, uncertainties regarding some of the radiative properties, and even more so when it comes to how an approximate treatment of them effects the radiation modelling. In this work the influence of the radiative properties of fuel particles is investigated. Moreover, application of approximate models to describe the properties of both gases and particles in modelling of the radiative heat transfer is evaluated. Detailed spectral models are applied are compared as a reference and compared against the approximate models. The results show that a grey treatment of combustion properties can be justified in the presence of fuel particles, errors are usually less than 10%. Conditions with only ash particles are more difficult to handle, but a non-grey WSGG model for the gas and grey particle properties is, in such cases, enough to give reasonable results.