Experimental Investigation Of Flame Stabilization In Scramjet Combustors

In scramjet supersonic combustion, strut and cavity flame-holder are used most extensively by now. The subsonic reversal flow behind the strut and in the cavity can be the important area for flame holding. Strut can achieve fuel equality distribution through bring fuel to the center of the supersonic flow. The cavity has good ability of flame hold, so the flame in the cavity can be the resident flame in the combustion. We adopt double struts combined cavity as the flame holder. The struts are disposed separately in upstream and downstream combustion for satisfying the mode transform, and are decussate for improving the distribution of the fuel.The combustor configuration has been designed for satisfying the experimental research by using UG software. The Fluent software was used to simulate flow field of the combustor in a Mach 2 and total temperature 1231K flow. The process of kerosene atomization and evaporation are simulated by using discrete phase mode, and the combustion is computed through the mode of finite-rate/eddy-dissipation turbulence-chemistry interaction. As results, the decussate disposition of struts realizes the well distribution of the fuel and increases the fuel mixture efficiency. The combination of the strut and cavity promotes the quality exchange in the cavity. With the combustor inlet Mach 2, the combustor could work well on condition that the kerosene equivalence ratio in upstream strut must be less than 0.1. The injection position and wedge of strut and double cavity have been investigated. Result indicates that the combustion efficiency increases as the first strut inject moving downstream and decreases as the second strut injection moving downstream. The construction of strut with wedge and double cavities can advance the combustion efficiency.Experiment and numerical investigation of supersonic combustion, using ethylene in different injection positions in the bottom wall of cavity flame holder was performed on direct-connect supersonic combustion test facility,for researching the influence of different positions in cavity to fuel combustion. The results of experiment and computation indicates that different injection positions for ethylene in cavity bottom wall have no influence on ignition, but combustion performance falls when injection position moving downstream.