A study on integrated aerodynamic-ramp-injector/gas-portfire in a supersonic combustor: Part one, numerical aspects

A computational study of an integrated aerodynamic-ramp(aeroramp) injector/gas-portfire has been conducted in an ethylene-fueled scramjet combustor, aiming at figuring out the performance of this novel injection and ignition/flame-holding system. The aeroramp injector consisted of two rows of two flush-wall holes, angled downstream and toed in to create vortex and enhance mixing. The gas-portfire was located downstream of the injector array. Turbulence was modeled with SST k-w turbulence model, and single step kinetics was used to model ethylene reaction kinetics. Under the simulated conditions: static pressure P₀ = latm, total temperature T_t =1231K, Ma = 2, the combustor operated in dual-mode combustion. Results showed that the gas-portfire integrated with aeroramp injector resulted in better fuel-air distribution, compared to aeroramp injector alone. Wall friction led to most part of the total pressure loss, however, the loss created by aeroramp injector/gas-portfire was a little. Successful combustion was obtained and the combustion efficiency varied in the range of 0. 5 - 0. 75. The gas-portfire acted as an igniter as well as a flameholder. Comparisons were made with experimental data, and it turned out that they were in good accordance with each other.