Laser Ablation Ignition Enhancement in a Cavity-Based Scramjet Combustor

This study examines the laser ablation (LA) ignition process in a scramjet combustor through integrated experimental and numerical methods. The effects of laser energy, ignition location, and cavity geometry on ignition performance are systematically investigated. High-speed [Formula: see text] chemiluminescence imaging was employed to visualize flame kernel development, while Reynolds-averaged Navier–Stokes (RANS) simulations were utilized to characterize the underlying flowfield. Results demonstrate that both laser energy and ignition location exert significant influence on flame kernel formation and subsequent flame stabilization. A modified cavity configuration featuring a secondary recess integrated into the base wall of the primary cavity was proposed and evaluated. This design achieved a 43% reduction in minimum ignition energy and markedly enhanced ignition stability. Numerical analyses further revealed that the secondary cavity attenuates thermal losses, promotes the formation of localized low-speed recirculation zones, and improves fuel–air mixing, collectively establishing a more conducive environment for ignition. The proposed geometry offers a novel and effective strategy for optimizing ignition in scramjet combustors.