Study on the effects of thermal throat on flame stabilization in a kerosene fueled supersonic combustor

The effects of thermal throat on flame stabilization in a kerosene fueled supersonic combustor were numerically and experimentally studied in the present paper. The results were obtained under the inflow condition of stagnation temperature 1100 K, stagnation pressure 1.0 MPa and Mach number 2.0. Wall pressure measurements and flame emission images were made during the experiments in an attempt to better understand the flame development, results showed the combustion organization scheme had a great effect on flame stabilization in the combustor. The flame development process in each case was different according to the flame luminosity pictures. When the pilot hydrogen was removed, the flame of case 1 and case 2 was still stable, and that of case 3 was blown off by the high-speed air flow, but it was surprised to find that the flame of case 4 was blowout even the pilot hydrogen existed. A shock train had generated in the isolator due to the thermal throat existing, which decreased the high-speed main stream, and increased the temperature and pressure, also enhanced the fuel mixing efficiency in the combustor, this was why the flame stabilization was achieved. But if the thermal throat disappeared, the shock train would be pushed out of the combustor by the high-speed air flow. The residence time for mixing, ignition and combustion was getting shorter, the flame was blown off finally.