Study on ignition mechanism and flame dynamic characteristics in a strut and cavity integrated bypass combustor.

This article systematically investigates the ignition characteristics, flame propagation mechanisms, and combustion dynamics of an integrated strut–cavity configuration in a bypass combustor, a key component of variable cycle engines designed for next-generation supersonic aircraft. Using combined experimental methods—including high-speed imaging—and numerical simulations alongside proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) analyses, the study demonstrates stable and efficient ignition performance across a broad range of operating conditions. It identifies inlet temperature as the dominant factor influencing lean ignition fuel–air ratios, describes a three-phase cavity ignition sequence, and reveals pressure-drop-dependent flame propagation patterns linked to flow field and fuel distribution changes. The findings also show that increased relative pressure drops enhance flame stability by modifying flame anchoring positions and turbulence characteristics, providing empirical foundations for optimizing bypass combustor designs.