固体火箭发动机液体喷射熄火模型

EXTIMCTION MODEL OF SOLID ROCKET MOTOR BY LIQUID INJECTION

关键词:  固体火箭发动机  液体燃料  燃料喷射  熄火  预测

Key words:  Solid rocket motor  Liquid fuel  Fuel spray  Flameout  Predction

摘要:

在实验研究的基础上,提出固体火箭发动机液体喷射熄火模型。该模型综合考虑了固体推进剂的瞬态燃烧、射流换热、液滴蒸发和发动机内弹道等耦合作用,成功地实现了对液体喷射熄火过程(临界参数和熄火用液量)的理论预示。理论研究发现液体喷射瞬变燃烧存在着临界喷射压降。当喷射压降大于该临界值时,熄火才能实现。随着推进剂能量的升高,临界喷射压降增加。随着喷射压降的增加,熄火用液量和降压速率分别下降和升高,其变化率逐渐减小。熄火用液量不存在最小值,因而在工程设计中,必须合理选择喷液量和喷射压强这两个设计参数。理论预示与实验结果吻合良好。

Abstract:

Based on the experimental studies,a theoretical model for liquid quench of solid rocket motor has been proposed. In the model, the coupling effects of internal ballistics of rocket motor,transient burning of solid pro-pellant, liquid drop evaporation and boiling heat transfer by liquid jet impinged on the burning surface are considered in detail. With application of the model, the liquid quench process of solid rocket motor (the critical injection pressure drop and the liquid quantity required for reliable extin-ction) is predicted theoretically.It is found from this theoretical study that there is a critical value of injection pressure drop required, for the liquid quench of rocket motor. Only when the injection pressure drop is greater than the critical value, can the extinction be achieved. The critical injection pressure drop for certain kind of prbpellant increases with increased piopellant energy. As the injection pressure drop increases, the liquid quantity required for reliable extinction decreases and the extinction speed increases, but their variation rates decreases. There is not a minimum liquid quantity value for extinction. Therefore,the parameteis,injection pressure drop, and liquid quantity to be injected, must be selected appropriately in the engineering design to obtain the best characteristics of the stop/ restart solid rocket motor with application of liquid injection technique. The theoretical results agrees well with the experimental ones.