Abstract: In order to reduce the production cost of the target drone and increase the thrust-to-weight ratio of the target drone engine, a solid rocket ejector-based combined engine model is put forward. It consists of a solid rocket and a reburning chamber. The layout can be divided into solid rocket built-in and solid rocket external. For getting the optimized layout structure of engine, the numerical simulation of flow in the built-in and external layout engines are carried out by quantitative heating in the reburning chamber simulating the engine working process. The calculation results show that for both the internal and external engine, the ejection efficiency is reduced with the increase of heating quantity under the same inlet ejecting area. The built-in layout engine thrust is basically unchanged, and the external layout engine thrust gradually increased. It has high thrust and thrust gain (maximum up to 39.3%). Thus, it can be seen that the external engine has better thrust performance. In order to further optimize the external layout engine, the performance of six cases of engines, i.e., the ratio of the ejection inlet size to the solid rocket outlet diameter (L/D) being set as 1/6, 2/6, 3/6, 4/6, 5/6, 6/6, are studied. The results show that as L/D increases from 1/6 to 6/6, the ejection efficiency, thrust and thrust gain increase first and then decrease. When L/D is equal to 4/6, the engine’s ejection efficiency and thrust are maximized and the engine’s performance is optimal.

Key words: Solid rocket;Ejecting engine;Ejection efficiency;Thrust gain;Numerical simulation

摘要： 为了降低靶机的生产成本，提高靶机发动机的推重比，建立了基于固体火箭引射式组合发动机模型，其结构包括固体火箭与再燃室，两者之间的布局可分为固体火箭内置式和固体火箭外置式，为了优化发动机布局结构，采用再燃室定量加热方法模拟发动机工作过程，分别对内置式及外置式布局发动机进行了数值计算。计算结果表明：在相同的入口引射面积条件下，随着加热量的增加，内、外置式发动机引射效率都降低，内置式布局发动机推力基本不变，外置式布局发动机推力逐渐增大，具有较高的推力及推力增益（最高达到39.3%）；由此可知，外置式发动机具有更好的推力性能。为了进一步优化外置式布局发动机，分别计算了引射口尺寸L与固体火箭出口直径D之比(L/D)为1/6，2/6，3/6，4/6，5/6，6/6的六种工况。结果表明：随着L/D从1/6增大到6/6，引射效率、推力及推力增益呈现先增大后减小的趋势，在L/D为4/6时，发动机引射效率和推力达到最大，此时发动机性能最优。

关键词: 固体火箭;引射式发动机;引射效率;推力增益;数值模拟