We conduct a high-speed visualization of coolant liquid film dynamics inside a 10N-class bipropellant thruster using monomethylhydrazine and a mixture of nitrogen tetroxide with approximately 3% nitric oxide as propellants at equivalent conditions with the flight model. The direct visualization of the liquid film inside a quartz glass chamber demonstrates the transient dynamics of film flow from ignition to cutoff for the first time. The scenario for the life of the film flow is found as follows: the coolant fuel jet impinges on the chamber wall being the liquid film; the friction force from the chamber wall rapidly decelerates the film as one-tenth of the injection velocity; next, the film moves sheared by the fast combustion gas downstream; and eventually the film completely evaporates by heat transfer from the hot combustion gas. The liquid film presents the typical ripple wave structure, covered by the velocity and thermal boundary layers. The effect of the mixture ratio is significant as the film flow rate increases at a small mixture ratio, leading to the longer film length.

我们在与飞行模型等效的条件下，使用单甲基肼和四氧化二氮和大约 3% 一氧化氮的混合物作为推进剂，对 10N 级双组元推进剂推进器内的冷却液液膜动力学进行高速可视化。石英玻璃室内液膜的直接可视化首次展示了从点火到截止的薄膜流动的瞬态动力学。薄膜流的寿命情况如下：冷却剂燃料射流撞击腔室壁是液膜；来自腔壁的摩擦力使薄膜以注射速度的十分之一迅速减速；接下来，薄膜被下游的快速燃烧气体剪切；最终薄膜通过来自热燃烧气体的热传递而完全蒸发。液膜呈现典型的波纹波结构，被速度边界层和热边界层覆盖。混合比的影响显着，因为在小的混合比下薄膜流速增加，导致更长的薄膜长度。