This paper proposes a combined flameholder comprising a pilot flameholder and a bluff body flameholder, interconnected by a radial V-gutter. The configuration of this combined flameholder is widely utilized in current afterburners and ram combustors, and its outstanding performance in future advanced combined cycle engines has been proved. To avoid the issue of uniform airflow at the inlet observed in most previous studies, this research installed a diffuser to simulate relatively realistic inlet airflow conditions of combustor. Particle Image Velocimetry (PIV) and high-speed camera are employed to measure the flow field structure of the combined flameholder, as well as the ignition flame evolution process under inlet Mach number of 0.3 – 0.5, temperature of 500 – 700 K, and pressure of 0.05 – 0.1 MPa. This paper reveals the combustion organization method of the combined flameholder through combining flow field characteristics and the ignition flame evolution process. Furthermore, the research findings indicate that flame evolution processes, flame projection area, and ignition delay time are significantly influenced by the inlet conditions. The variations in these flame evolution characteristics with different inlet conditions are summarized and the contributing factors are analyzed. The results of the paper are expected to serve as a reference for the optimization and design of flame stabilization systems in current and future afterburners and ram combustors.
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