Ethylene Transverse Jets in Supersonic Crossflows

Flowfield and flame-holding characteristics of ethylene jets were examined experimentally. Flow visualization and CH * chemiluminescence images were obtained in a shock tunnel. Model configurations with and without a cowl or a cavity were tested for jet-to-freestream momentum flux ratios varying from 1.35 to 3.07. Flame-holding characteristics were studied using a cavity configuration with a cowl. Four flow conditions with the total temperature varying from 1610 to 2320K were studied keeping the overall fuel-air equivalence ratio at 0.2. The data showed that shock impingement due to the cowl influenced the jet to penetrate shallower into the freestream than for the case without the cowl. The shock impingement reduced the fluctuating level of the jet's periodical motion. At 2080 K, combustion was maintained inside the cavity, and this condition provided a continuous ignition downstream of the cavity (i.e., flaming holding is achieved at a much lower enthalpy than seen in the existing data). At 2320 K, the trend was similar. At temperatures lower than 2080 K, the flame holding was not maintained.