Effects of LOx Post Recess on the Combustion Characteristics for Bi-Swirl Coaxial Injector

Kim, Seung-Han; Han, Youkyung; Seo, Seonghyeon; Moon, Il-Yoon; Kim, Jong-Kyu; Seol, Woo Seok

doi:10.2514/6.2005-4445

Cited by 15 publications

(10 citation statements)

References 6 publications

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“…While changing chamber pressure and OFR, the results were acquired from three hot-firing tests for each injector head and are presented in this paper. Similar to the unielement combustor (Kim et al, 2005;Seo et al, 2010a), the pressure drop across the injector increases with the recess number. It is thought that the flame anchored inside the recessed region in the swirl coaxial injector confines flows of LOx and kerosene like the recess in the shear coaxial injector does (Candel et al, 2006;Kendrick et al, 1999;Lux and Haidn, 2009).…”

Section: Experimental Technique and Conditionmentioning

confidence: 92%

“…As the recess number increases above 1.0, the LOx film impinges against the kerosene film inside the fuel nozzle (internal mixing). The present injector configurations are the same as those in the previous researches (Kim et al, 2005;Seo et al, 2010a). The calculated film thickness and the swirl angle for LOx and kerosene are 0.84 and 0.40 mm and 65 and 122 , respectively.…”

Section: Injector Designmentioning

confidence: 93%

“…All four different type injectors have the same geometric dimensions except for the recess length between the oxidizer injector post tip and the fuel nozzle tip. The recess number (RN) is defined as a dimensionless parameter, which divides the recess length (L 1 ) by the distance between the oxidizer post tip and the colliding point of the oxidizer sheet on the fuel nozzle wall (L 2 ), RN=L 1 =L 2 (Kim et al, 2005). When the recess number is below 1.0, the LOx and kerosene sheets mix and interact outside the fuel nozzle (external mixing).…”

Section: Injector Designmentioning

confidence: 99%

“…Static pressure and mass flow rate data in 1 s, 100 samples, were usually averaged during steady-state condition, as shown in Figure 3a. The stagnation pressure at the nozzle inlet was estimated by converting the measured static pressure at the nozzle inlet using specific heat ratio and Mach number calculated from the CEA code (Gordon and McBride, 1996;Kim et al, 2005).…”

Section: Combustion Performancementioning

confidence: 99%

“…The effects of the oxidizer post recess in unielement combustors with various swirl coaxial injectors were examined by Kim et al (2005) and Seo et al (2010a). The larger recess number caused time-averaged combustion chamber pressure and characteristic velocity to improve at almost constant mass flow rate and oxidizer-to-fuel ratio (Kim et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effects of Injector Recess and Chamber Pressure on Combustion Characteristics of Liquid–Liquid Swirl Coaxial Injectors

Ahn

Han

Seo

et al. 2010

Combustion Science and Technology

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Combustion characteristics such as combustion performance and combustion stability have been studied experimentally using a small liquid rocket thrust chamber with 19 liquid-liquid swirl coaxial injectors. Data were obtained from static pressure, temperature, and dynamic pressure sensors installed in propellant manifolds and the combustion chamber. While changing the recess length of the injector, characteristic velocity and pressure fluctuation data were collected and analyzed. In addition, chamber pressure was varied between 42 and 54 bar, which covers the sub-and supercritical pressures of oxygen. The results show that the longer recess length generally promotes combustion performance and the spray interaction between injectors in the multielement combustor increases the characteristic velocity. When the chamber pressure is above the critical pressure of oxygen, the recess length scarcely affects the pressure fluctuation. However, when the chamber pressure is below the critical pressure, the shift from external mixing to internal mixing of oxidizer and fuel sheets by the variation of recess length significantly degrades combustion stability and induces strong low-frequency instability. Accordingly, the effects of both recess length and operating chamber pressure must be taken into consideration when designing liquid-liquid swirl coaxial injectors.

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Section: Experimental Technique and Conditionmentioning

confidence: 92%

Section: Injector Designmentioning

confidence: 93%

Section: Injector Designmentioning

confidence: 99%

Section: Combustion Performancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of Injector Recess and Chamber Pressure on Combustion Characteristics of Liquid–Liquid Swirl Coaxial Injectors

Ahn

Han

Seo

et al. 2010

Combustion Science and Technology

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Study on spray patterns of gas-centered swirl coaxial (GCSC) injectors in high pressure conditions

Kim

Han

Choi

et al. 2013

Aerospace Science and Technology

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Cryogenic fluid dynamics of pressure swirl injectors at supercritical conditions

Zong

Yang

2008

Physics of Fluids

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A comprehensive numerical analysis has been conducted to explore the development of liquid-oxygen ͑LOX͒ flow in pressure swirl injectors operating at supercritical pressures. The model is based on full-conservation laws and accommodates real-fluid thermodynamics and transport phenomena over the entire range of fluid states of concern. Three different flow regimes with distinct characteristics, the developing, stationary, and accelerating regimes, are identified within the injector. Results are compared to predictions from classical hydrodynamics theories to acquire direct insight into the flow physics involved. In addition, various flow dynamics are investigated by means of the spectral and proper-orthogonal-decomposition techniques. The interactions between the hydrodynamic instabilities in the LOX film and acoustic oscillations in the gaseous core are clearly observed and studied. The influences of flow conditions ͑mass flowrate, swirl strength of the injected fluid, and ambient pressure͒ and injector geometry ͑injector length and tangential entry location͒ on the injector flow behavior are systematically characterized in terms of the LOX film thickness and spreading angle. The axial and azimuthal momentum exchange and loss mechanisms are also examined.

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Effects of LOx Post Recess on the Combustion Characteristics for Bi-Swirl Coaxial Injector

Cited by 15 publications

References 6 publications

Effects of Injector Recess and Chamber Pressure on Combustion Characteristics of Liquid–Liquid Swirl Coaxial Injectors

Effects of Injector Recess and Chamber Pressure on Combustion Characteristics of Liquid–Liquid Swirl Coaxial Injectors

Study on spray patterns of gas-centered swirl coaxial (GCSC) injectors in high pressure conditions

Cryogenic fluid dynamics of pressure swirl injectors at supercritical conditions

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