Planar laser-induced fluorescence imaging of kerosene injection in supersonic flow

The kerosene vapor distribution was visualized using planar laser-induced fluorescence (PLIF) technique in a model scramjet engine combustor in Ma 2.52 flow with stagnation temperature of 1486 K. Two cavities were equipped in the flow path, and the qualitative distribution of kerosene vapor was observed and recorded in the downstream cavity. Two representative injection schemes, i.e., parallel and transverse injections, are compared with variation of pre-injection pressures. High signal-to-noise ratio kerosene-PLIF images are acquired. For parallel injection, the kerosene distribution in the downstream cavity is significantly affected by the existence of the upstream cavity. Only a small portion of fuel propagates to the downstream, resulting in a fuel-lean environment in the cavity. In the case of transverse injection, the fuel is largely entrained to the downstream cavity by the recirculation flow, creating a fuel-rich environment in the cavity. The kerosene-PLIF is verified to be a powerful tool for the investigation of fuel distribution for scramjet applications. Graphical abstract