Global Radiative Modeling for Hydrogen-Blended Natural Gas Combustion Medium and Numerical Application

Abstract

Abstract. Accurate prediction of H2-blended combustion requires advanced radiation modeling as the radiation model plays a critical role in the turbulence–chemistry–radiation coupling inherent to such flames. To address the issue of accurately predicting the gas and soot thermal radiation characteristics in natural gas combustion blended with a high ratio of hydrogen, an improved global thermal radiation model based on the weighed-sum-of-gray-gases (WSGG) principle was proposed. The proposed model containing H2O and CO2 was developed based on a line-by-line (LBL) method using the HITEMP 2010 database. The coefficients were applicable to a total pressure range of 1–10 atm, a temperature range of 400–2500 K, a H2O/CO2 molar ratio range of 2.25–5, and a partial pressure path length range of 0.001–60 atm · m, verified using benchmark emissivity and a series of one- and two-dimensional heat transfer cases. The proposed WSGG model was then applied to the numerical simulation of a 40-kW combustion furnace. The results were compared with those obtained using a default model of fluent software, and the influence of soot radiation inclusion was discussed, indicating that pressurization and the presence of soot enhance radiative heat transfer, and the improved global model can perform more accurate medium radiation calculations compared to the previous model developed for conventional fuels, which provide a basis for furnace design of hydrogen-blended natural gas combustion.