The combustion of an oxygen/paraffin hybrid rocket motor was experimentally characterized. Firing tests were conducted for different oxidizer mass fluxes ranging from 2.47 to 3.40 g/ (cm²·s). Variations in temperature and H₂O partial pressure at the nozzle exit were diagnosed using mid-infrared tunable diode laser absorption spectroscopy (TDLAS) based on H₂O absorption near 2.5 μm. Three H₂O absorption lines were simultaneously covered by only one distributed feedback (DFB) laser using scanned-wavelength direct absorption (DA) mode with 2.0 kHz repetition rate. Measurement uncertainty was analyzed in detail considering line-strength uncertainty and Voigt fitting residuals. A two-dimensional (2D) model of the nozzle was constructed using the ANSYS FLUENT CFD software package. The combustion efficiency of the hybrid rocket motor was evaluated from the perspectives of chemical reaction and heat release, respectively, based on TDLAS results and CFD simulations. The effectiveness of the evaluation was validated by comparing its results with characteristic velocity (C*)-based combustion efficiency. Finally, comparisons of combustion efficiencies among different cases show that increasing the oxidizer mass flux or oxidizer-to-fuel ratio improves the combustion efficiency of the hybrid rocket motor under our experimental conditions.

氧气/石蜡混合火箭发动机的燃烧实验进行了表征。对不同的氧化剂质量通量范围为2.47至3.40 g /（cm ² ·s）进行了焙烧测试。基于2.5μm附近的H ₂ O吸收，使用中红外可调二极管激光吸收光谱（TDLAS）诊断喷嘴出口处的温度和H ₂ O分压的变化。三H ₂使用扫描波长直接吸收（DA）模式以2.0 kHz重复频率，仅用一台分布式反馈（DFB）激光器同时覆盖O条吸收线。考虑线强度不确定度和Voigt拟合残差，对测量不确定度进行了详细分析。使用ANSYS FLUENT CFD软件包构建了喷嘴的二维（2D）模型。基于TDLAS结果和CFD模拟，分别从化学反应和放热的角度评估了混合动力火箭发动机的燃烧效率。通过将评估结果与特征速度（C*）为基础的燃烧效率。最后，在不同情况下燃烧效率的比较表明，在我们的实验条件下，增加氧化剂的质量通量或氧化剂/燃料比可以提高混合火箭发动机的燃烧效率。