固液火箭冲压发动机工作性能分析

固液火箭冲压发动机兼具固体火箭冲压发动机和液体燃料冲压发动机的优点,为了研究其性能,建立了理论分析模型,计算了设计点性能以及非设计点工作特性.结果表明,固液火箭冲压发动机的比冲高于固体火箭冲压发动机,当液固比为1时,比冲提高1.82倍,液固比越大,比冲越高;随余气系数的增加设计点比冲先增加而后减小;非设计点比冲随飞行马赫数的增加先增加而后减小,对应不同的飞行高度,有一个临界点使比冲最大,高度越低临界点马赫数越小;推力系数随飞行高度的增加而增加,低马赫数下的比冲随飞行高度的增加而减小,高马赫数下的比冲随高度的增加先增加而后减小.按等余气系数调节燃油流量会使发动机性能变化较大,要获得稳定的飞行性能应研究其他的加热规律.

Characteristics analysis of solid-liquid ducted rocket

The solid-liquid ducted rocket (SLDR) has advantages of solid ducted rocket (SDR) as well as liquid fuel ramjet (LFR). In order to analyze the characteristics of SLDR, a mathematics model was established and several proper parameters were presented. The characteristics calculation method was presented as well. According to calculating results, the specific impulse of SLDR is higher than SDR. When the mass ratio of liquid/solid propellant reaches 1, the specific impulse can be improved 1.82 times. With excess air coefficient increasing, the specific impulse increases firstly and then decreases. At off-design conditions, the specific impulse increases and then decreases with Mach number increasing. There is a critical Mach number that makes the specific impulse to be largest and this critical Mach number decreases with flight height. The thrust coefficient increases and the specific impulse decreases with fight height increasing.