Identification of multi-regime detonation development for hydrocarbon fuels

Recently, a detonation response diagram with multiple nonmonotonic boundaries was identified for syngas/air mixtures (Pan et al., 2022), accounting for wide-ranging operation conditions with thermal inhomogeneities. In this work, we have identified the detonation response diagrams of various fuels, especially large hydrocarbons, initiated by temperature gradients under engine-relevant conditions, in both planar and spherical configurations. Results show significant differences in the multi-regime detonation development for different fuels due to reactivity sensitivities and thermophysical properties. Furthermore, the curvature effect in the spherical configuration can cause substantial degeneration of the detonation development, while cool flame partial oxidation of large hydrocarbons can greatly facilitate robust detonation development, suggesting the significance of the interaction between flow inhomogeneities and chemical kinetics.