Radiative heat transfer calculation in combustion systems

Resumo

With an increasing trend towards cleaner combustion, accurate prediction of radiation of molecular gases is beginning to occupy a position of central importance in the design of gases-fired combustion appliances. The radiative heat transfer in absorbing- emitting gas mixtures can be most accurately predicted using line-by-line approach, but line-by-line calculations require large computer resources and computational time. Due to the increasing interest in applying the spectral integration of radiative transport equation in practical applications, several real gas models were developed. In the present work, a local-spectrum correlated model called cumulative wavenumber model (CW) is adopted and the spectral properties of the gases are obtained from HITRAN and HITEMP databases. The spectral radiative transport equation is solved using the CW model and the discrete ordinates method. Validation in gray and non-gray cases is presented by comparison with result of literature. Then, 2D axis symmetric furnace domain containing high temperature gases of combustion is modeled. The results are compared with a benchmark line-by-line results and Full Spectrum Correlated-k distribution model (FSCK) results taken of the literature. Scenarios investigated for non-isothermal and non-homogeneous mixtures of gases show that the CW approach is accurate to line-by-line solution. The development algorithms can be used in thermographic participating media calculations in combustion systems.