Numerical exploration of mixing and combustion in a dual-mode combustor with backward-facing steps

Abstract

Dual-mode scramjet combustor is the crucial component for the combined cycle engine of space mission vehicles. The Reynolds Averaged Navier-Stokes (RANS) equations, Spalart-Allmaras turbulence model and the finite-rate reaction model have been utilized to investigate the mixing and combustion in a dual-mode combustor with backward-facing steps, and the species distributions and the Mach number profile of a turbulent diffusion combustion problem have been employed to validate the numerical approach. Moreover, the influences of the injection strategy and the fuel equivalence ratio arrangement on its mixing and combustion flow fields have been explored. The obtained results show that the vertical injection is beneficial for mode transition, and an obvious high pressure region is generated with the vertical injection strategy. Accordingly, its mass-weighted average Mach number drops more sharply. The lower total equivalence ratio is beneficial for the mixing augmentation, as well the smaller fuel equivalence ratio discrepancy. However, the larger total equivalence ratio is beneficial for the mode transition.

Reduced-order modeling of supersonic fuel–air mixing in a multi-strut injection scramjet engine using machine learning techniques

“…The hyper-parameters are respectively: scaling factor, kernel bandwidth, 𝜎, radial distance of the GPR kernel function, 𝑟 2 , the number of hidden layers, cost for independent parameter optimization,  𝑖 , and the learning rate, 𝛼. We also show the overall 𝑅 2 The SHAP values in Fig. 10 show that the strut V-settlement angle has more importance than other design variables on the mixing efficiency in the stations close to the struts.…”

“…A dual-mode ramjet/scramjet (DMR) engine has a great potential to be one of the most promising air-breathing propulsion systems for hypersonic air transportation in the near future [1,2]. Its appeal stems from a number of features.…”

Combustion Modes and Unsteady Characteristics during the Condition Transition of a Scramjet Combustor

“…The equations were solved by a density-based double precision solver. The combustion process was simulated by the finite-rate/no TCI model and one-step ethylene-air chemical reaction mechanism [40]. The second-order upwind scheme was adopted to discretize the turbulent kinetic energy, specific dissipation rate, and energy equations in space.…”

Experimental Investigation on Pyrolysis of n-Decane Initiated by Nitropropane under Supercritical Pressure in a Miniature Tube

“…With the development of aeroengines for advanced aircrafts with hypersonic or supersonic speed, , endothermic hydrocarbon fuel has been proposed as a good solution for thermal management issues resulting from high intensity combustion in the combustion chamber and high friction with air at high flight speeds. − Endothermic hydrocarbon fuels with a chemical heat sink due to the occurrence of endothermic pyrolysis reactions can take the place of conventional fuels in which the heat-absorbing capacity is limited by a physical heat sink. , Improving the chemical endothermic capacity is essential to increase the heat absorption of endothermic hydrocarbon fuel.…”