Validation of spectral gas radiation models under oxyfuel conditions - Part C: Validation of simplified models

Combustion of hydrocarbon fuels with pure oxygen results in a different flue gas composition as combustion with air. Standard CFD spectral gas radiation models for air combustion are out of their validity range. The series of three articles provides a new spectral basis for the validation of new developed models. In part C of the series the total emissivity calculated by the most common spectral models were compared with benchmark calculations by the line-by-line database HITEMP2010. The models were compared at path length from 0.001. m to 100. m and at temperatures from 800. °C to 1800. °C for atmospheres of pure gases and of various combustion processes with different fuels. The range of fuels was natural gas, brown coal and anthracite and the combustion processes were air blown and oxyfuel combustion with wet and with dry recirculation. The statistical narrow band models RADCAL and EM2C, the exponential wide band model and the statistical line width model were chosen as composition independent models. A number of weighted sum of grey gases models from different authors were chosen as computational efficient models especially developed for oxyfuel combustion. The statistical narrow band model EM2C had the least deviations of up to 12%. The weighted sum of grey gases model from Johansson et al. (2011) was the most valid and versatile model for computational efficient simulations of spectral gas properties with an accuracy of 21%.