Fluids and Soft Matter

In this study, the effects of the fuel distribution of the 8 micro jets through a two-strut in the scramjet Engine are fully addressed. The main concentration of this work is to calculate the structure of the fuel jet in micro-jet conditions and compare it with the common injection method. Therefore, a CFD study was applied to study the fuel jet interactions in the supersonic stream of Mach = 2. The hydrogen diffusion in the supersonic flow is comprehensively investigated. Both cold injection and combustion using micro jets were quantitatively analyzed. This simulation solves the Reynolds Average Navier-Stocks equations of a high-speed multi-phase compressible flow. The chemical reaction solver relied on the modified CHEMIKEN GRI-3. The German Aerospace Center (DLR) scramjet engine experiment verified and validated the model. The simulation data showed an agreement with the experimental results. Therefore, the model was utilized to compare the two designs: with a 1 mm hole and with 8 micro jet holes in the back side of the strut.

The results show an enhancement in the fuel mixing with the application of the microjet ejectors. Along the engine length, the hydrogen concentration decreases with advancing combustion. The drop in the hydrogen concentration was highly intense in the first few 10 mm. Just after 10 mm from the injector, the hydrogen concentration dropped to 50% and to 30% in the case of one-hole injectors, and micro injectors, respectively. Also, the combustion efficiency increased by 5% and the maximum flame temperature increased from 2200 K to 2400 K.

The study recommends using the microjet injectors in the strut-based scramjet engine to be able to reach high combustion efficiency.