Wide band correlated-k approaches for non-grey radiation modelling in oxy-fuel combustion with dry recycling

Increased CO2 and H2O concentrations in oxy-fuel combustion promote radiation compared to conventional air based technologies. Spectral radiation models are necessary to calculate the radiative properties of CO2 and H2O. In the present study, the wide band correlated-k method (WBCK) is evaluated for non-grey radiative transfer calculations in oxy-fuel combustion. Several WBCK formulations are presented and applied to virtual gas turbine combustors for both air and oxy-fuel combustion with dry recycling involving strongly varying H2O/CO2 ratios. The spectral formulation of the WBCK is the most exact approach, but leads to excessive computational times. The multiple gases formulation using three optimised absorption coefficient is found to be the optimum choice regarding accuracy and computational efficiency. The results of a standard weighted-sum-of-grey-gases method strongly deviate from those of the WBCK.