Combustion Mode and Mixing Characteristics of a Reacting Jet in Crossflow

Understanding of flame anchoring in a jet in crossflow (JICF) configuration is vital to the design of fuel injectors in combustion devices. The present study numerically investigates a hydrogen-rich jet injecting perpendicularly into hot vitiated crossflow using direct numerical simulation (DNS). The governing equations of low-Mach-number multicomponent reactive flows are solved, with a chemical mechanism for hydrogen-air flames containing 13 species and 35 reactions. The mixture-averaged multispecies transport model is employed to calculate the diffusion terms. Development of the reacting flow field and flame shape along the jet trajectory is depicted. The flame is found to be anchored around the jet exit and downstream only on the windward side. The heat release rate and chemical explosive mode analysis (CEMA) are used to identify combustion modes. Distinct from flames stabilized in nonvitiated crossflow, diffusion flame is dominant under the current conditions, though some premixed or partially premixed regions are found on the leeward side of the jet due to turbulent mixing. The near-field mixing of the reacting JICF is quantified by spatial unmixedness, in both two-dimensional (2D) and three-dimensional (3D) space.

Automated summary

This study numerically investigated the flame anchoring of a hydrogen-rich jet injecting perpendicularly into hot vitiated crossflow. The flame was found to be anchored around the jet exit and downstream only on the windward side. Diffusion flame was dominant, though some premixed or partially premixed regions were found on the leeward side due to turbulent mixing.