A pintle injector is advantageous for throttling a liquid rocket engine and reducing engine weight. This study ex- plores the effects of momentum ratio and Weber number at various injection conditions on spray charact...A pintle injector is advantageous for throttling a liquid rocket engine and reducing engine weight. This study ex- plores the effects of momentum ratio and Weber number at various injection conditions on spray characteristics of the pintle injector for liquid-gas propellants. A liquid sheet is injected from a center pintle nozzle and it is broken by a gas jet from an annular gap. The pressure drops of propellants, and the pintle opening distance were consi- dered as control variables; using 0.1 -1.0 as a bar for the pressure drop of the liquid injection, a 0.01-4）.2 bar for the pressure drop of gas jet and a 0.2 - 1.0 mm for the pintle opening distance. The discharge coefficient was de- creased linearly before the pintle opening distance of 0.75 mm and then, the coefficient was slightly increased. Spray images were captured by a CMOS camera with high resolution. Then, the shadow and reflected images were analyzed. Spray distributions were measured by a pattemator with an axial distance of 50 mm from a pintle tip. Finally, the spray half angles had an exponentially decreasing correlation as a momentum ratio divided by the Weber number. Also, the spray half angles from the spray distribution were underestimated compared to those measured from the captured images.展开更多
基金supported by Advanced Research Center Program(NRF-2013R1A5A1073861)through the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)contracted through Advanced Space Propulsion Research Center at Seoul National University
文摘A pintle injector is advantageous for throttling a liquid rocket engine and reducing engine weight. This study ex- plores the effects of momentum ratio and Weber number at various injection conditions on spray characteristics of the pintle injector for liquid-gas propellants. A liquid sheet is injected from a center pintle nozzle and it is broken by a gas jet from an annular gap. The pressure drops of propellants, and the pintle opening distance were consi- dered as control variables; using 0.1 -1.0 as a bar for the pressure drop of the liquid injection, a 0.01-4）.2 bar for the pressure drop of gas jet and a 0.2 - 1.0 mm for the pintle opening distance. The discharge coefficient was de- creased linearly before the pintle opening distance of 0.75 mm and then, the coefficient was slightly increased. Spray images were captured by a CMOS camera with high resolution. Then, the shadow and reflected images were analyzed. Spray distributions were measured by a pattemator with an axial distance of 50 mm from a pintle tip. Finally, the spray half angles had an exponentially decreasing correlation as a momentum ratio divided by the Weber number. Also, the spray half angles from the spray distribution were underestimated compared to those measured from the captured images.
