Laminar flame speed correlations for dual fuel flames in high-pressure conditions

The usage of methane as a fuel stands out as a transition strategy to zero carbon energy conversion processes. However, methane is difficult to be made to burn due to its strong molecular structure. To mitigate this issue, a mixture of methane and a more ignitable fuel may be a promising solution for large scale combustion applications. In many of those, the corresponding CFD setup can be very demanding and detailed chemistry may be replaced by simplified approaches, such as laminar flame speed methods. To contribute with robust and reliable modeling of combustion processes fueled by dual fuel mixtures, novel formulations are proposed to improve accuracy of laminar flame speed correlations. To accomplish this task, numerical simulations of 1D freely propagating laminar flames based on detailed chemistry are conducted for various pressures and equivalence ratios. Kinetic mechanisms are obtained from the literature and evaluated with available experimental data. For the best performing mechanism, the resulting laminar flame speeds are mapped based on fresh mixture composition and correlated through power-law wholly empirical equations. The proposed formulations show clear improvements when compared to other existing methods.