This research is an investigation of the flame spread opposed to a liquid oxidizer flow in a solid fuel duct. Several firing tests were conducted using liquid oxygen as the oxidizer and solid poly methyl methacrylate (PMMA) as the fuel. The results indicate that the flame spread rate decreased with increasing oxidizer port velocity and decreasing port diameter. This study reveals through visual confirmations and empirical correlations of the flame spread rate that the flame spread opposed to liquid oxygen in a solid fuel duct can be classified as stabilized combustion. Extinction and abnormal regression were observed when oxidizer port velocity was high and port diameter was small. Furthermore, the cooling of the solid fuel by the liquid oxygen flow had a strong effect on the transition between normal regression and extinction, or abnormal regression. A model of the flame spread rate which considers the heat balance at the fuel surface assuming a fully developed thermal boundary layer is introduced and shown to agree well with the experimental results. Lastly, it is revealed that the difference in kinematic viscosity between liquid oxygen and gaseous oxygen is the main reason dependency of port diameter on flame spread rates differs between the liquid oxygen tests in this study and gaseous oxygen tests in previous studies.

这项研究是对与固体燃料导管中的液体氧化剂流动相反的火焰蔓延的研究。使用液态氧作为氧化剂和固态聚甲基丙烯酸甲酯（PMMA）作为燃料进行了多次燃烧测试。结果表明，随着氧化剂通道速度的增加和端口直径的减小，火焰的蔓延速率降低。这项研究通过视觉确认和火焰蔓延速率的经验相关性揭示，固体燃料导管中与液态氧相反的火焰蔓延可归为稳定燃烧。当氧化剂端口速度高而端口直径小时，观察到消光和异常消退。此外，液态氧流对固体燃料的冷却对正态回归和灭绝之间的过渡有很大影响，或异常回归。引入了一个火焰扩散率的模型，该模型考虑了燃料表面的热平衡，并假设其完全形成了热边界层，并显示出与实验结果非常吻合。最后，揭示了液态氧和气态氧之间运动粘度的差异是端口直径对火焰扩散速率的依赖性的主要原因，该研究中的液态氧测试与先前的研究中的气态氧气测试之间存在差异。