Injection structures can affect the ignition and combustion of fuel and supersonic air in scramjets, strongly impacting their performance. The influence of three different injection structures on the performance of a solid scramjet was investigated using direct-connect tests. The experiment employed a boron-based fuel-rich propellant and simulated a flight Mach number 5.6 at 25 km. The results show that, compared to a circular nozzle (test no.1), the elliptical nozzle (test no.2) can significantly improve the ignition and combustion of the fuel-rich mixture produced in the gas generator. This improvement is even more significant when a two-stage elliptical nozzle is adopted (test no. 3). The combustion of the fuel-rich mixture presents the typical cycle of establishment, development, maintenance, and decay. The wall ablation area and particle deposition distribution, show that the gaseous components in the fuel-rich mixture burn rapidly, and that particles deposition increases when an elliptical nozzle is used. The combustion efficiency of test no.3 reached 0.60, which is larger than the 0.48 obtained during test no.1. The low particle combustion efficiency is a key factor limiting solid scramjets performance.

喷射结构会影响超燃冲压发动机中燃料和超音速空气的点火和燃烧，严重影响其性能。使用直连试验研究了三种不同喷射结构对固体超燃冲压发动机性能的影响。该实验使用了一种基于硼的富燃料推进剂，并在 25 公里处模拟了 5.6 马赫数的飞行。结果表明，与圆形喷嘴（试验编号1）相比，椭圆喷嘴（试验编号2）可以显着改善气体发生器中产生的富燃料混合物的点火和燃烧。当采用两级椭圆喷嘴时，这种改进更加显着（测试编号 3）。富燃料混合物的燃烧呈现出典型的建立、发展、维持和衰变循环。壁烧蚀面积和颗粒沉积分布表明，富燃料混合物中的气体成分燃烧迅速，当使用椭圆喷嘴时，颗粒沉积增加。试验3的燃烧效率达到0.60，大于试验1的0.48。低颗粒燃烧效率是限制固体超燃冲压发动机性能的关键因素。