高速空気流とエチレンを模擬した窒素の混合に関する研究

抄録

Nitrogen and helium was injected from various geometry injectors to a Mach 2.5 airstream to simulate ethylene fuel and hydrogen fuel injection in a supersonic combustor. Penetration height and mass fraction of nitrogen and helium were compared after normalizing for fair comparison. Penetration height was normalized with a length scale, which took the difference in mass flow rate at equivalence ratio of unity for different gases into account. On the other hand, mass fraction was converted into local equivalence ratio. When a circular injector was used, penetration height of nitrogen plume decreased by 40% in comparison with that of helium. So-called stinger shaped injector had high penetration than the circular injector in the condition of low dynamic pressure ratio for both gases. Penetration height of nitrogen plume from the stinger shaped injector was lower than that of helium plume and the maximum value of local equivalence ratio in case with nitrogen injection was higher than that in case with helium injection. And there was not much different in growth of penetration height and attenuation of maximum equivalence ratio between the case of nitrogen injection and helium injection.