Variable-area injectors are suitable choices for developing throttleable rocket engines because it is difficult to efficiently control thrust when fixed-area used. A pintle injector a variable-area that can the mass flow rate of propellants, thereby replacing large plate having several elements with single unit. To achieve proper performance under all throttling conditions, design procedure was established based on spray characteristics. The angle and Sauter mean diameter droplets were...

This study investigates the onset and decay mechanisms of sheet cavitation within a chamfered orifice under turbulent conditions, using high-speed backlight imaging for detailed frame-by-frame analysis. A distinctive metastable regime was identified, distinguished by its unique hysteresis behavior during with ability to control periodicity through variations in numbers. new appears at high numbers, contrary typical expectations inception, highlighting potential risk range safe operation...

Although fuel spray parameters, such as cone angle and penetration length, are crucial for developing high-efficiency high-performance combustion engines, general models predicting transient characteristics of these parameters have not been suggested. In this study, the cyclopentane at sub- transcritical conditions relevant IC engine rocket injections were experimentally evaluated. A single simplified model angles lengths over time was developed by adopting artificial neural networks (ANN)....

Movable pintle injectors are installed in bipropellant rocket engines to control the mass flow rate of propellants and allow deep throttling with high combustion performance. A thin liquid sheet is formed by ejecting radially around end pintle. This broken axially injecting a gas propellant from an annular gap nozzle. The device features movable rod, which allows thickness be changed. volume fluid modeling used estimate varying sheet, equal opening up critical point. procedure these results...

To investigate a hypothesis of the orifice flow-induced instability in rocket engine thrust chambers, single liquid oxygen (LOX) injector with an optically accessible module was used for experiments, water as simulant LOX. The unsteady pressure downstream measured using high-speed piezoelectric sensors under cavitating and non-cavitating intra-injector flow conditions. flows were directly visualized via backlight imaging camera through module. Cavitation initiated at cavitation number 2.05,...

Effects of injection conditions on a pintle injector which is proper to recent liquid rocket engines requiring low cost, weight, high efficiency and reusability were studied. The with typical moving was used for atmospheric experiment using water air. Injection pressures considered 0.5 1.0 bar, 0.1 bar air 0.2 mm opening distance. Sauter mean diameters (SMD) spray measured at 50 distance from tip SMD treated as representative parameter in this study. As result, because shape characteristics...

모사 추진제로 물과 공기를 사용하여 상압 상태에서 핀틀 인젝터의 개도가 액체-기체 분무에 미치는 영향을 실험적으로 연구하였다. 액체 공급 압력은 0.1 bar에서 1.0 bar 까지, 개도는 0.2 mm에서 mm 까지의 다양한 분사 유량 계수와 질량 유량을 계산하였다. 분사각은 역광 기법을 이용하여 얻어진 이미지에서 측정하였다. mm인 경우 정상적인 액막이 형성되지 않았고, 비 균질한 분사를 보였다. 이는 연소실 내부에 연소 불안정을 가져올 수 있다. 개도를 계산된 운동량 플럭스 비는 분사각에 약한 상관관계를 갖고 있고, 분사각과 강한 운동량이 증가할수록 지수 함수적으로 감소하였고, 약 40도로 수렴하였다. Effects of opening distance on liquid-gas spray pintle injector were experimentally investigated under atmospheric condition by using water and air as...

The flame structure of ethanol and nitrous oxide combustion was experimentally studied using a tricoaxial injector at various momentum flux ratios. objects the study were to investigate effects additional supplement that gas jets inject outer annular gap injection velocities obtain analyze structure. fully developed patterns due transfer viscosity mixing similar axial flow when measurement position increased from Z/d = 1 10. correlation equation, ratio, used along with linear regression...

Injection coupling is a well-known cause of high-frequency combustion instability in hydrogen/liquid oxygen ([Formula: see text]) rocket engines. This type commonly explained by the two-way between dynamics chamber and injection system. Recent experimental studies BKD combustor, however, suggest that LOX injector could be self-excited driving acoustic mode chamber. To assess feasibility this mechanism, here, we study both experimentally theoretically stability isolated from The was performed...

The pressure and temperature during liquid rocket engine ignition drastically increase because of energy generation from the severe combustion reaction pure oxidizer fuel. Studies on oxygen/kerosene are scarce. This research observes transition a gaseous spray by directly visualizing flow field using windowed combustor high-speed shadowgraph imaging technique. hydrodynamic characteristics propellant feed system investigated before experiments analyzing time responses injection pressures...

ABSTRACT The gas-centerd swirl injectors are widely used on the main combustor of large liquid propellant rocket engines. Since gas-liquid propellants, such as kerosene and oxygen-rich gas combination, mixed burned in high pressure condition over critic al point, cold-flow spray test atmospheric can not represent actual pattern. To observe near patterns gas-centered injector, chamber control system were constructed. operating sequence was controlled precisely to obtain clear visualization...