化学平衡对高速飞行器推进系统性能影响的研究

On Accurately Computing Thrust of Air-BreathingCombined Engine in High Speed Vehicle

采用一种快速收敛且稳定性好的算法,考虑在高速飞行器的推进系统性能的计算过程中,化学平衡对性能的影响。通过比较发现,若不考虑化学平衡的影响,误差有时可达10%。因此,在模拟高速飞行器推进系统的性能过程中,必须考虑化学平衡效应。

To our best knowledge, there is no detailed information on taking chemical equilibrium into consideration in computing performance of air-breathing combined engine in any paper in the open literature. Consideration of chemical equilibrium is essential to accurately computing thrust, fuel consumption, etc of air-breathing combined engine in high speed vehicle. Combined engine consists ofturbofan engine and ramjet engine. Section 1 analyzes in much detail the effect of chemical equilibrium on turbofan engine. Subsection 1. 2 deals with the effect of chemical equilibrium on combustion process of engine. Subsection 1. 3 deals with expansion process of engine. Subsection 1. 4 deals with its performance computation; Figs. 3 (without afterburner) and 4 (with afterburner) give the variations of percentage increases of weight of fuel (kerosene), specific fuel consumption, and thrust respectively caused by chemical equilibrium with flight Mach number. From Figs. 3 and 4, we know that the effect of chemical equilibrium on turbofan performance is indeed considerable. Section 2, taking advantage of what has been analyzed in section 1, briefly analyzes the effect of chemical equilibrium on ramjet engine. Fig. 6 is computed for liquid hydrogen as fuel of ramjet engine. Fig. 6 gives the variations of percentage increases of temperature, specific fuel consumption, and thrust respectively caused by chemical equilibrium with flight Mach number. Percentage increases of thrust and specific fuel consumption of ramjet engine are even more marked than those of turbofan engine.