Real gas effects on the laminar flame speed of hydrogen-methane-oxygen mixtures

The laminar flame speed (LFS) of H 2 -CH 4 -O 2 mixtures has been calculated over a wide range of conditions using both the ideal gas (IG) and the complete Redlich-Kwong (RK) gas models. The ratio β = X CH 4 / ( X CH 4 + X H 2 ) was 0-1, the equivalence ratio was 0.5-2, the initial temperature was 300 K, and the pressure was 10/20/30 MPa. In H 2 -rich/CH 4 -rich mixtures, the real gas (RG) effects tend to increase/decrease the LFS with respect to the IG cases, leading to an overall promoting, neutral, or inhibiting impact on the LFS. At 10/20/30 MPa, the RG effects change the LFS by −10.5%/-11.8%/-5.2% to +7.3%/+16.5%/+25.9% compared to the IG case. While the laminar burning flux (LBF) is close in RG and IG for CH 4 -rich conditions, difference of up to about 7% can exist for H 2 -rich conditions, indicating an increased impact of non-ideal thermodynamic properties, thermal conductivity, and reaction rates compared to CH 4 -rich mixtures.