Study of Combustion Characteristics of Hybrid Rocket Engine with Swirling Liquid Oxygen Flow and its Application to Small Sounding Rocket Engine

通过在氧化剂流中施加旋流，我们研制的GO_2和PMMA混合火箭发动机获得了良好的性能。2001年，我们在日本发射了首枚1.8米长的混合火箭，创下了混合火箭首次成功飞行的纪录。作为下一级，构建了具有旋涡液氧流的混合火箭发动机系统。为了研究直接暴露于液态氧的PMMA的燃烧过程，进行了小型混合燃烧室的试验，该燃烧室有一个单端口，充满液态氧或液态氧，没有旋转。结果表明：液氧层在表面形成，液氧的蒸发决定了液氧/PMMA的燃烧过程。混合火箭发动机的燃烧实验表明，混合火箭发动机的燃料回归速率、C^*效率和Isp均小于混合火箭发动机的燃料回归速率、C^*效率和Isp，导致混合火箭发动机的性能低于混合火箭发动机。燃烧室壁面液氧层的存在，由于角动量的损失、净Go的降低和燃烧时间的延长，降低了燃烧特性。燃烧振荡称为“嘎吱”模式也发生了。为改善燃烧性能差的问题，采用液氧混合火箭发动机的蓄热式冷却喷管。对喷嘴进行了热分析，制作了一种含液氧的纵向通道壁式再生冷却喷嘴。在以液氧为冷却剂的汽化实验中，分别对混合动力火箭发动机燃烧用氧气的质量流量和液氧通过喷管的质量流量进行了研究，考察了液氧的汽化条件。经证实，液氧通过喷嘴安全汽化。研制了1500-N推力混合火箭发动机。利用GO2进行了燃烧试验，取得了良好的效果。实现该项目目的的未来问题是将再生冷却液氧喷管与探空火箭的旋氧型混合火箭发动机相匹配。少

By applying swirl to an oxidizer flow, our hybrid rocket engine with GO_2 and PMMA could obtain the high performance. In 2001, we launched the first hybrid rocket of 1.8m in length, which recorded the first successful flight of a hybrid rocket, in Japan. As the next stage, a hybrid rocket engine system with a swirling LOX flow was constructed. In order to investigate combustion processes of directly exposed PMMA to LOX, tests of a small hybrid combustor with a single port filled with LOX or GOX without swirling were carried out. It was found that a LOX layer appeared on the wall and combustion processes of LOX/PMMA are determined by evaporation of LOX.Experiments of combustion in a hybrid rocket engine with a swirling LOX flow showed that fuel regression rate, C^* efficiency and Isp of the hybrid rocket engine with the swirling LOX flow were smaller than those with the swirling GOX flow, resulting in lower performance of the hybrid rocket engine with LOX than that with GOX. The existen … More ce of a LOX layer on the combustion chamber wall decreased the combustion characteristics due to the loss of the angular momentum, the decrease of the net Go and the longer combustion time. Combustion oscillation called a "Chugging" mode also occurred.To improve the poor combustion performance, a regenerative-cooling nozzle of the hybrid rocket engine using LOX was adopted. Thermal analysis of the nozzle was performed, and a longitudinal channel-wall type regenerative-cooling nozzle with LOX was made. Vaporization experiments with LOX as the coolant, in which the mass flow rates of the oxygen used for combustion of the hybrid rocket engine and LOX passing through the nozzle were independently supplied to examine vaporization conditions of LOX, were conducted. It was confirmed that LOX was safely vaporized through the nozzle.A 1500-N thrust hybrid rocket engine was made. The burning test using GO2 was carried out and showed good performance. The future issue to achieve this project purpose is to match the regenerative-cooling LOX nozzle with the swirling oxygen type hybrid rocket engine for a sounding rocket. Less