Longitudinal combustion instability of a pintle injector for a liquid rocket engine combustor

Sakaki, Kazuki; Funahashi, Tomokazu; Nakaya, Shinji; Tsue, Mitsuhiro; Kanai, Ryuichiro; Suzuki, Kyohei; Inagawa, Takahiro; Hiraiwa, Tetsuo

doi:10.1016/j.combustflame.2018.04.017

Cited by 42 publications

(9 citation statements)

References 19 publications

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“…Fang and Shen (2017) obtained the effects of the structure parameters on SMD, droplet size distribution uniformity index, and spray angle. Sakaki et al (2015) and Sakaki et al (2018) used the ethanol/liquid oxygen pintle injector to evaluate the performance of a rocket engine. Nardi et al (2015) also designed a pintle injector engine and conducted experiments.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Spray Characteristics With Upstream Flow Pulsation of a Pintle Injector

Xie

Nie²,

Gao³

et al. 2022

Front. Aerosp. Eng.

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The volume of fluid (VOF) model and the adaptive mesh refinement (AMR) method are used to study the spray characteristics of a gas–liquid pintle injector and the effects of mass flow pulsation of liquid on it. A pintle injector is a thrust adjusting device that changes the injection area using movable parts. Pressure pulsation in the supply pipeline is simulated by periodically changing the mass flow rate of the inlet. Spray characteristics with constant and pulsating upstream flows are compared with each other. The effect of frequency and amplitude of upstream liquid flow pulsation on the spray performance was studied. The results reveal that holding the mass flow rate of the upstream liquid flow constant, under the impact of gas flow, the liquid block, the liquid filament, and a large number of small droplets are peeled off from the liquid film. The film breakup position stays relatively fixed, and the spray has a conical shape. However, when the upstream liquid flow is pulsating, the film breakup position changes periodically, and the spray has a “Christmas tree”-shape. The pulsation frequency has little effect on the spray angle. But it strongly determines the droplet size and the spatial distribution of the spray. In addition, the pulsation amplitude can enhance the phenomenon of “Christmas tree.” With the increase in pulsation amplitude, the liquid film at the outlet of the pintle injector appears with a periodic phenomenon of “contraction–expansion.”

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Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Spray Characteristics With Upstream Flow Pulsation of a Pintle Injector

Xie

Nie²,

Gao³

et al. 2022

Front. Aerosp. Eng.

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“…Combustion instabilities and efficiency were measured and analyzed while changing TMR, O/F ratio, and propellant injection velocity. [9][10][11] In a rocket engine, spraying conditions, spray characteristics, and combustion characteristics are closely intercorrelated. Spray characteristics are determined by spraying conditions and determine the combustion characteristics.…”

Section: Introductionmentioning

confidence: 99%

Droplet Size Control in Gas-Liquid Pintle Injectors

Kim

Lee

Yoon

2021

Trans. Japan Soc. Aero. S Sci.

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Due to their suitable characteristics for throttleable rocket engines, interest in pintle injectors has been recently renewed. Many studies have focused on the correlation between spraying conditions and spray or combustion characteristics for pintle injector. However, there is no previous study on the correlation between spray and combustion characteristics due to the difficulties in controlling each spray characteristic individually. This research presents a solution to this problem. For the control group, a 400 N gas-liquid pintle injector for liquid oxygen and gas methane is designed and its spray characteristics are measured through cold-flow tests. In sequence, a 'reverse injection' idea and its design are proposed to increase spray angle while maintaining the droplet size, which is represented by the Sauter mean diameter. In addition, in the design proposed, the reverse injection effect is intensified as the throttling level increases, decreasing the difference of spray angle between throttling levels. In a cold-flow test, air and water were used under an atmospheric condition for gas-liquid flow simulant. The spray angle and droplet size were measured using the shadow method. The 'reverse injection' feature proposed functioned properly, increasing the spray angle of the injector while maintaining the droplet size.

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“…It typically leads to large-amplitude pulsating oscillations of thermodynamic properties, such as pressure, temperature and velocity [2]. Over the past few decades, how to design a stable combustion system in the absence of such self-sustained pulsations [3] is a major challenge for power generation [4], aeronautics [5,6], and aerospace propulsion [7,8] industrial sectors. Thermo-acoustic instability occurs due to the 'constructive' coupling/loop between acoustics and unsteady heat release from a heat source (typically either a flame or an electrical heater) [9].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics-Acoustics Coupling Studies on Self-Excited Combustion Oscillations Maximum Growth Rate

Zhao

2020

J. Therm. Sci.

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Unlike electric vehicles and electric aircrafts, hydrocarbon-fuelled (fossil) engine systems are much noisier. By conducting one-step chemical reaction-thermodynamics-acoustics coupling studies and experimental measurements, we explore the universal physics of how hydrocarbon-fuelled combustion is a noise maker. We also explain that how combustion-sustained noise at a particular frequency ω is intrinsically selected. These frequencies correspond to the acoustic resonance nature of the combustor. We find that a reacting gas in which the rate of chemical reacting increases with temperature is intrinsically and naturally unstable with respect to acoustic wave motion, since its modal growth rate α is greater than 0. Acoustic disturbances tend to exponentially i.e. exp(αt) increased first and then are limited by nonlinear effects and finally grow into limit cycle oscillations. The growth rate α is found to increase first and then decrease with the gradient of the heat release rate with respect to the temperature change, i.e. heat capacity. The maximum (α/ω) max depends on the specific heat ratio γ, which is related to the speed of sound. The unstable nature could be changed by introducing some acoustic dissipative/damping mechanism, such as the boundary layer viscous drag and boundary losses. It is shown that such losses could lead to increased critical heat capacity, below which stable combustors can be designed. Finally, the acoustical energy consisting of both potential and kinetic energy is found to grow exponentially faster by 100% than the acoustic disturbance amplitude.

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Longitudinal combustion instability of a pintle injector for a liquid rocket engine combustor

Cited by 42 publications

References 19 publications

Numerical Investigation on Spray Characteristics With Upstream Flow Pulsation of a Pintle Injector

Numerical Investigation on Spray Characteristics With Upstream Flow Pulsation of a Pintle Injector

Droplet Size Control in Gas-Liquid Pintle Injectors

Thermodynamics-Acoustics Coupling Studies on Self-Excited Combustion Oscillations Maximum Growth Rate

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