基于光学诊断的某新型含铝推进剂燃烧特性分析

为探究某新型含铝固体推进剂燃烧特性和规律，在模拟固体发动机的高压条件下，采用可调功率激光器结合高速摄影、发射光谱等光学诊断技术对该新型含铝固体推进剂开展了系统的点火及燃烧过程研究。通过对该推进剂的点火延迟、退移速率、燃烧温度以及团聚物颗粒尺寸的定量测量和分析，明确了该推进剂的点火延迟量级；证实此推进剂的退移速率严格遵循Summerfield燃速公式；判断出其最高燃烧温度高于3 300 K，且随压力增大而升高；通过对燃烧过程中发光凝聚相产物面积的量化分析得出推进剂产物中团聚物粒径尺寸受环境参数的影响规律。

Investigation of combustion characteristics of a new aluminum-containing propellant based on optical diagnosis

In order to investigate the combustion characteristics of a new aluminum-containing solid propellant, the ignition and combustion process of the propellant at elevated pressure for simulating the solid propellant rocket engine were systematically studied by using a variable power fiber-laser and optical diagnostic techniques. The near-infrared fiber laser was employed to ignite the propellant slices placed in a high-pressure optical tank which was designed and manufactured for simulating solid propellant rocket engine conditions. The successive images of the laser-ignition and combustion process were captured by a high-speed camera while the optical emission spectroscopy was recorded with fiber-based spectrometers. Therewith, the regression rate, the ignition delay, and agglomerate particle size of the propellant were determined from the quantitative measurement and analysis of the former, likewise, the combustion temperatures were deduced by the latter. Accordingly, the maximum combustion temperature, the magnitude of the ignition delay, and rules of regression rate were mastered, as well as their dependence on laser power and ambient pressure. Firstly, the analysis of emission spectra shows that the maximum combustion temperature of this propellant should be higher than 3 300 K which grows with pressure. It reveals that the fundamental mechanisms of the propellant receding rate and ignition delay are affected by the ambient pressure from the perspective of chemical reaction dynamics. Meantime, the exponential decay law of ignition delay is determined while its formation mechanism is explored, based on the real-time monitoring of the propellant burning surface with high spatial and temporal resolution. Furthermore, it is also found that the regression rate of this propellant increases rapidly at low pressure, but appears to be saturated gradually when the ambient pressure exceeds 4 MPa. Whereafter, it is confirmed that the receding rate rules strictly follow the Summerfield burning rate equation. Finally, through the quantitative analysis of the luminous area of agglomerates in the combustion process, the effects of the agglomerate particle size in the propellant product by environmental parameters are concluded.