关键词: 推进剂;凝胶;喷嘴;雾化;燃烧

Abstract: Aiming at elucidating the detailed spray characteristic of gelled methylhydrazine/nitrogen tetroxide(MMH/NTO), visual experiment was conducted to investigate the phenomena involved in the spray and combustion process of gelled MMH/NTO in a visualized square combustion chamber with a single injector. Triplet impinging injector，fuel-oxidizer-fuel(F-O-F) and oxidizer-fuel-oxidizer(O-F-O) were used in the experiment. Through closing the middle channel temporarily, the spray images of gelled MMH and NTO using 90° like-impinging injector were obtained by high-speed camera firstly, then spray images of gelled MMH/NTO using triplet impinging injector in hot-fire were obtained with the help of high-speed camera. Spray cone angle, breakup length were obtained by image processing technology, then the effect of nozzle type, jet velocity were discussed. The results show that small droplets were seen in the spray images of gelled NTO mainly, however, the atomization of gelled MMH is poor due to high viscosity, only liquid sheets and filaments throughout the entire field of view were seen in the spray images of gelled MMH, hence liquid sheets and filaments seen in the spray images of gelled MMH/NTO in hot-fire test are mainly gelled MMH. Comparing with the spray cone angle of gelled MMH using 90°like-impinging injector, the spray cone angle of gelled MMH/NTO using triplet impinging injector of F-O-F type is smaller, so the energy utilization efficiency of F-O-F type triplet impinging injector is lower. The spray cone angle of gelled MMH/NTO using O-F-O type triplet impinging injector is bigger than that using F-O-F type triplet impinging injector, and the breakup length of gelled MMH/NTO using O-F-O type triplet impinging injector is shorter, so the atomization of gelled MMH/NTO using O-F-O type triplet impinging inject is better.

Key words: Propellant;Gel;Injector;Spray;Combustion