氢氧涡流燃烧推力器设计方案仿真研究

Simulation Study on Design of Hydrogen-Oxygen Vortex Combustion Thruster

涡流燃烧冷壁液体火箭发动机具有燃烧室侧壁温度低的特点,在高空或空间氢氧推力器应用方面很有优势,但是喷管喉部高温限制了它的应用。本文对以气氢气氧为推进剂的涡流燃烧冷壁发动机的设计方案进行了仿真研究,指出涡流工质的选择是燃烧室设计的首要问题,应根据燃烧反应总包方程,以体积流量较大的推进剂作为涡流工质,而并非一定是氧化剂。氢氧涡流燃烧推力器的仿真结果表明,采用氢气作为旋涡工质,可以有效缓解氧气为旋涡工质时喷管壁面温度对混合比的限制,达到较高的比冲和材料容许的较低的喷管内壁温度;半球形头部的燃烧室方案虽然性能较高,但是头部内侧燃气容易聚积、温度过高,不利于长时间工作;采用椭球形头部、平行于轴线的头部氧气喷注形式可以达到较好的性能,并且头部和喷管内壁燃气温度均较低;喉部最高燃气温度随混合比增大而升高,氧化剂与燃料混合比达6时的最高温度为1382K。

The vortex combustion cold-wall liquid rocket engine has the characteristic of low side-wall temperature of combustion chamber,which has advantages in high-altitude or space hydrogen-oxygen thruster applications,but the high temperature of nozzle throat limits its applications. The design scheme of a vortex combustion cold-wall engine with gas hydrogen and oxygen as propellant is simulated. It is pointed out that the selection of the working fluid of vortex is the primary problem in the combustion chamber design. According to the global equation of combustion reaction,propellant with larger volume flow rate should be used as the working fluid of vortex,not necessarily oxidant. The simulation results of hydrogen-oxygen vortex combustion thruster show that the use of hydrogen as the working fluid of vortex can effectively alleviate the restriction of nozzle wall temperature on mixture ratio when oxygen is used as the working fluid of vortex,and achieve higher specific impulse and lower nozzle inner wall temperature allowed by materials. Although the performance of the combustion chamber with hemispherical faceplate is higher,the gas inside the head is easy to accumulate and the temperature is too high,which is not conducive to long-term working. The results show that the best performance can be achieved by using the ellipsoidal faceplate and the oxygen injection parallel to the axis,and the gas temperature of the inner wall of faceplate and nozzle is low. The maximum gas temperature in the throat increases with the increase of the mixture ratio,and the maximum temperature is 1382K when mixture ratio is 6.