The Effects of the Ambient Pressure on Self-Pulsation Characteristics of a Gas/Liquid Swirl Coaxial Injector

Im, Jaehyun; Yoon, Youngbin

doi:10.2514/6.2008-4850

Cited by 8 publications

(15 citation statements)

References 4 publications

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“…The self-pulsation characteristics of the LCSC injector are greatly influenced by injection conditions and injector geometrical parameters. The frequency of self-pulsation is linearly proportional to the liquid and gas axial Reynolds number [5] and is more dependent on the liquid Reynolds number [6]. The ambient pressure suppresses self-pulsation and decreases self-pulsation domain [4,6].…”

Section: Introductionmentioning

confidence: 97%

“…In another paper [9], they suggested that Kelvin-Helmholtz-like instabilities on conical liquid sheet surfaces are likely to excite self-pulsation. Im et al [5,6] studied the self-pulsation of LCSC injectors systematically and concluded that self-pulsation occurs due to the dominant wave of the liquid sheet. Huang et al [10] pointed out that self-pulsation is a result of resonance because is no extra vibration driver, and it is impossible to resonate between vapor and liquid states.…”

Section: Introductionmentioning

confidence: 98%

“…The selfpulsation frequency is the frequency at which the spray oscillates. It can be obtained from either a series of instantaneous spray images or acoustic frequency because self-pulsation is accompanied by an intense screech [5], and the frequency of the spray oscillation is the same as that of the acoustic [11]. The self-pulsation characteristics of the LCSC injector are greatly influenced by injection conditions and injector geometrical parameters.…”

Section: Introductionmentioning

confidence: 99%

“…As self-pulsation can cause pressure and flow rate oscillations, and finally those oscillations can amplify the combustion instability in rocket engines, self-pulsation must be suppressed [5,6]. To control self-pulsation, a thorough mechanism of selfpulsation is needed.…”

Section: Introductionmentioning

confidence: 99%

“…Self-pulsation characteristics include self-pulsation boundary and frequency. Because the occurrence of self-pulsation depends on both injection conditions and injector geometrical parameters [5], selfpulsation boundaries divide the injection conditions into pulsation and stable zones at predefined geometrical parameters. The selfpulsation frequency is the frequency at which the spray oscillates.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effects of Recess on the Self-Pulsation Characteristics of Liquid-Centered Swirl Coaxial Injectors

Kang

Cheng

et al. 2016

Journal of Propulsion and Power

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The self-pulsation characteristics of liquid-centered swirl coaxial injectors have been investigated using a Photron Fastcam SA-1.1 camera and a PULSE system (B&K Corp., 3650 type). The effects of both recess length and injection condition were analyzed and discussed. The flow pattern in the recess chamber of a liquid-centered swirl coaxial injector can be classified into three types, namely, outer, critical, and inner mixing flow. Once the critical flow approaches, self-pulsation is about to occur. When self-pulsation occurs, the spray oscillates with a Christmas tree shape. The Christmas-tree-like spray periodically produces droplet clusters, making horizontal spray width and mass flux oscillate periodically. Self-pulsation is the strongest when the flow is around the critical mixing flow. Both variations of recess length and injection condition can change the flow pattern in the recess chamber. When the flow pattern moves away from the critical mixing flow, self-pulsation is suppressed. All the frequency behaviors of selfpulsation indicate that self-pulsation is strongly related to Kelvin-Helmholtz instability. A possible mechanism of selfpulsation is also presented. This mechanism interprets the experiments of the present study and the results of literature well. Nomenclature D = diameter or distance, m h = film thickness, m k = specific heat ratio L = length, m _ m = mass flow rate, kg∕s P = pressure, Pa R = swirling radius or gas constant T = temperature, K u = axial velocity, m∕s w = circumferential velocity, m∕s α = spray angle, deg Δ = difference θ = convergent angle of the pressure swirl injector, deg μ = dynamic viscosity, Pa · s ρ = density, kg∕m 3 σ = pressure ratio φ = recess angle, deg Subscripts a = atmosphere cr = critical l = liquid li = liquid injector g = gas ir = inner or = outer r = recess s = swirl chamber t = tangential hole

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of Recess on the Self-Pulsation Characteristics of Liquid-Centered Swirl Coaxial Injectors

Kang

Cheng

et al. 2016

Journal of Propulsion and Power

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Periodic atomization characteristics of simplex swirl injector induced by klystron effect

Yang¹,

Yang²,

Xu³

et al. 2018

Chinese Journal of Aeronautics

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Numerical Study on the Self-Pulsation Characteristics of LOX/GH2 Swirl Coaxial Injector

Qiao,

Liang,

Liu

et al. 2024

International Journal of Aerospace Engineering

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To investigate the self-pulsation characteristics of a liquid-centered swirl coaxial injector with liquid oxygen (LOX) and gas hydrogen (GH2) as the working mediums under supercritical condition, a numerical simulation was employed. The transient simulation of the flow and injection process of cryogenic propellant was carried out using the RNG k−ε turbulence model, VOF model, and Peng-Robinson equation of state. The frequency spectrum of calculated pressure oscillation agreed with the experimental data. The amplitude-frequency characteristics of recess region, LOX, and GH2 paths when self-pulsation occurs were analyzed. The effects of operating parameters, such as the flow rate of LOX or GH2 and the initial GH2 temperature, on the self-pulsation, were evaluated specifically. Results reveal that the self-pulsation results from the periodic variation of pressure and velocity caused by the periodic blocking of annular gas by the liquid sheet. The dominant frequencies of pressure oscillation in the recess region, upstream of LOX, or GH2 path are diverse. But for the points in each region, the dominant frequency is about the same. When the LOX/GH2 mixing ratio increases, the liquid sheet thickness and the number of liquid filaments increase. The position where filaments are massively broken into droplets moves further downstream. For the same mixing ratio, the flow rate of LOX has a greater impact on the atomization features. The pressures corresponding to low or high frequency increase when the initial GH2 temperature raises. The higher temperature would shift the dominant oscillation between the low and high regimes.

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The Effects of the Ambient Pressure on Self-Pulsation Characteristics of a Gas/Liquid Swirl Coaxial Injector

Cited by 8 publications

References 4 publications

Effects of Recess on the Self-Pulsation Characteristics of Liquid-Centered Swirl Coaxial Injectors

Effects of Recess on the Self-Pulsation Characteristics of Liquid-Centered Swirl Coaxial Injectors

Periodic atomization characteristics of simplex swirl injector induced by klystron effect

Numerical Study on the Self-Pulsation Characteristics of LOX/GH2 Swirl Coaxial Injector

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