Effects of inlet configuration on ignition and fuel regression behind a backstep

Five step configurations were designed to investigate the effects of inlet step configurations on the now structure and ignition of solid fuel behind a backstep. Experiments were conducted separately in a cold flow for the flowfield measurement and in a hot flow for the fuel regression before ignition and ignition tests, The step height was fixed at 29 mm for each configuration. The inlet velocity of the cold flow was 15 m/s. The velocity flowfield was measured with a laser Doppler anemometer anti the ignition process was observed with a video camera, The configuration of the inlet step significantly affected the turbulence intensity of the shear layer and the reverse now rate of the recirculation zone, The greater reverse flow rate provided a better flameholding capability, and hence, abbreviated the ignition delay, As the flow was turbulent, the higher the turbulence intensity and the longer the ignition delay When the oxygen concentration was higher than 19%, the effect of inlet configuration on ignition diminished.