Quantifying the Variation of the Mass Flow Rate Generated in a Simplex Swirl Injector by Pressure Fluctuation

Khil, Taeock; Kim, Sung-Hyuk; Cho, Seongho; Yoon, Youngbin

doi:10.2514/6.2008-4849

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…Then, the inflow velocity was computed based on instantaneous pressure drop and the radius of the core surface at the head end. Recently, a research group in Korea [8,9] pulsed the flow in the range of frequencies of 100-300 Hz and presented the experimental data for the pressures and mass flow rates. Experimental results have also been published by Ahn [10] and Ahn et al [11], whose work is aimed at achieving response data in the broader frequency range, possibly the same as in Bazarov's [1] experiments.…”

mentioning

confidence: 99%

Dynamic Response of Rocket Swirl Injectors, Part I: Wave Reflection and Resonance

Ismailov

Heister

2011

Journal of Propulsion and Power

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Linear analyses are developed to theoretically investigate how disturbance waves are reflected and transmitted in the vortex chamber of a classical swirl injector. The dependence of the magnitude of the wave reflection process on the disturbance frequency is derived, and it is shown that this dependence may exhibit distinct maximum values. It is explained that the frequencies at which maximum response occurs are termed the resonant frequencies of the swirl injector. In general, resonant conditions will depend not only on the geometry of the injector but also on the particular flow conditions. In other words, for a given injector geometry, there are specific flow conditions that may produce resonance. A simple formula is derived for the primary resonance, which corresponds to a quarter-wave oscillation within the vortex chamber. Two different resonance theories are presented that vary in their level of accuracy of description of the flow transition from the vortex chamber to the nozzle. Results are provided for both of these models.

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confidence: 99%

Dynamic Response of Rocket Swirl Injectors, Part I: Wave Reflection and Resonance

Ismailov

Heister

2011

Journal of Propulsion and Power

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“…When the mass flow of the supply system oscillates, the shape of the gas core will also change accordingly. Khil [6] conducted that the air core of the chain shape is caused by the integration of the Klystron effect and swirl in the swirl chamber. Cheng [7] investigated that air core oscillates propagates in a long wave manner in the injector.…”

Section: Introductionmentioning

confidence: 99%

Study on the Influence of Low-Frequency Flow Oscillation on the Atomization Characteristics of Gas-Centered Coaxial Centrifugal Nozzle

Kang

Tong²,

Jiang³

et al. 2023

J. Phys.: Conf. Ser.

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The dynamic atomization characteristics of gas center coaxial centrifugal nozzle under the condition of pressure oscillation in the supply system were studied by applying external excitation through the flow pulsator. Obtaining spray image by high-speed photography while using hydro-mechanical pulsator to get generate of supply system. The results show that the spray width changes periodically with low-frequency pressure oscillation. For self-pulsation sprays, it is challenging to maintain a “Christmas tree” shape with low-frequency oscillation. Pressure oscillation can effectively suppress spray self-pulsation. However, the pressure oscillation amplitude may be much larger than that of the self-pulsation itself. Therefore, the premise of applying this method is that the applied external excitation cannot stimulate or amplify the combustion instability. The gas post-pressure drop determines the amplitude and frequency of the self-pulsation, while the excitation frequency will slightly affect the amplitude and frequency of the self-pulsation.

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“…More recently, investigations in South Korea [11] and the United States [12][13][14][15][16] have amplified on the initial body of work. Bazarov's initial theory [9] shows some opportunity for injector resonance at intermediate frequencies, but the recent work of this group has established a simple relationship [12,14] to approximate resonant frequencies using the analogy of waves entering a harbor of a fixed volume.…”

Section: Introductionmentioning

confidence: 99%

“…Hydromechanical pulsators tend to drop off in pulsation amplitude at these frequencies, but they have been used successfully in a number of studies [11,17]. Piezoelectric devices are capable of much higher frequencies, but pulsation amplitudes (stroke lengths) tend to be somewhat limited.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study Swirl Injector Dynamic Response Using a Hydromechanical Pulsator

Ahn

Ismailov

Heister

2012

Journal of Propulsion and Power

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The dynamic response of a classical (simplex style) swirl injector has been studied experimentally using a superscale transparent model with water as the working fluid. A unique mechanism was developed for imparting controlled perturbations to the injector inlet mass flow by successively blocking and opening tangential inlet flow passages using a rotating cap over the inlet ports. Two vortex chamber designs (long and short) were evaluated to assess the effect of this important design variable. High-speed imaging of the spray cone and air core/liquid interface inside the vortex chamber was used to assess dynamic behavior at frequencies up to 500 Hz. Resonant conditions were detected in both designs, and both measurements gave similar frequencies for the resonant peak. The resonant peak was compared against recent theory due to Ismailov and Heister ("Dynamic Response of Rocket Swirl Injectors, Part I: Wave results compare well only when the theory is adjusted to account for potential water hammer effects induced by the rotating cap. Nomenclature D n = diameter of nozzle, in. L v = effective vortex chamber length including 1 2 nozzle contraction length, in. L vc = vortex chamber length, in. P manifold = manifold pressure, psi P ullage = ullage pressure, psi R in = radius to centerline of inlet channel, in. R n = radius of nozzle, in. R t = radius of tangential inlet, in. R vc = radius of vortex chamber, in. r vc = radius of air core in vortex chamber, in. v t = velocity in tangential inlets = core disturbance amplitude (half-air-core diameter amplitude over mean diameter) avg = average total (included) spray angle, deg 0 = total spray angle fluctuation amplitude, deg

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Quantifying the Variation of the Mass Flow Rate Generated in a Simplex Swirl Injector by Pressure Fluctuation

Cited by 6 publications

References 7 publications

Dynamic Response of Rocket Swirl Injectors, Part I: Wave Reflection and Resonance

Dynamic Response of Rocket Swirl Injectors, Part I: Wave Reflection and Resonance

Study on the Influence of Low-Frequency Flow Oscillation on the Atomization Characteristics of Gas-Centered Coaxial Centrifugal Nozzle

Experimental Study Swirl Injector Dynamic Response Using a Hydromechanical Pulsator

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