Injector-Driven Flame Dynamics in a High-Pressure Multi-Element Oxygen–Hydrogen Rocket Thrust Chamber

Armbruster, Wolfgang; Hardi, Justin; Suslov, Dmitry; Oschwald, Michael

doi:10.2514/1.b37406

Cited by 38 publications

(20 citation statements)

References 30 publications

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“…Its occurrence is usually reasoned by the proximity of injector resonance frequencies to combustion chamber acoustic modes. Verification of this hypothesis from the corresponding flame response through optical observations in the combustion chamber is rare [9,10]. Examples of coupling with the LOX injector can also be found in some experiments operating with LOX∕CH 4 [11,12].…”

mentioning

confidence: 99%

Experimental Investigation of Self-Excited Combustion Instabilities in a LOX/LNG Rocket Combustor

Martin

Armbruster

Hardi

et al. 2021

Journal of Propulsion and Power

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mentioning

confidence: 99%

Experimental Investigation of Self-Excited Combustion Instabilities in a LOX/LNG Rocket Combustor

Martin

Armbruster

Hardi

et al. 2021

Journal of Propulsion and Power

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“…The focus of this study is a detailed investigation of the flame response to the excited injector acoustics. The spatial mode shapes of the flame response to the LOX injector acoustics have been investigated and published [2].…”

Section: Methodsmentioning

confidence: 99%

“…Spatial mode shapes of the flame dynamics in OH* and blue radiation at the acoustic eigenfrequencies of the LOX posts can be found in Ref. [2]. However, from the DMD spatial modes it is difficult to understand the dynamics of the flame which lead to the intensity variation in the longitudinal direction.…”

Section: Lox Core Dynamic Response To Excited Injector Eigenmodesmentioning

confidence: 99%

Experimental Investigation of Injection-Coupled High-Frequency Combustion Instabilities

Armbruster¹,

Hardi²,

Oschwald³

2020

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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Self-excited high-frequency combustion instabilities were investigated in a 42-injector cryogenic rocket combustor under representative conditions. In previous research it was found that the instabilities are connected to acoustic resonance of the shear-coaxial injectors. In order to gain a better understanding of the flame dynamics during instabilities, an optical access window was realised in the research combustor. This allowed 2D visualisation of supercritical flame response to acoustics under conditions similar to those found in European launcher engines. Through the window, high-speed imaging of the flame was conducted. Dynamic Mode Decomposition was applied to analyse the flame dynamics at specific frequencies, and was able to isolate the flame response to injector or combustion chamber acoustic modes. The flame response at the eigenfrequencies of the oxygen injectors showed symmetric and longitudinal wave-like structures on the dense oxygen core. With the gained understanding of the BKD coupling mechanism it was possible to derive LOX injector geometry changes in order to reduce the risks of injection-coupled instabilities for future cryogenic rocket engines.

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“…Experimental and computational research on shear coaxial injectors using a gaseous annular propellant and a central cryogenic jet for liquid rocket engine applications were carried out by Poinsot et al [4], Rey et al [5], Richecoeur et al [6][7][8], Méry et al [9], Hakim et al [10,11], Urbano et al [12], Gonzalez-Flesca et al [13], Urbano et al [14], Hardi et al [15,16], Gröning et al [17], Armbruster et al [18], Mayer and Krülle [19], Mayer and Tamura [20], Mayer et al [21], Oefelein and Yang [22], Zong and Yang [23,24], Roa and Talley [25], Roa et al [26], Forliti et al [27], Hua et al [28], Graham et al [29], Levya et al [30,31], Rodriguez et al [32], Wegener et al [33], and Davis and Chehroudi [34]. Aspects of those studies that focused largely on characterizing and understanding the atomization, flame locations, and average global behavior for shear coaxial flows that are not experiencing combustion instabilities were reviewed by Roa and Talley.…”

Section: Introductionmentioning

confidence: 99%

Transverse Acoustic Forcing of Gaseous Hydrogen/Liquid Oxygen Turbulent Shear Coaxial Flames

Roa

Talley

2021

Journal of Propulsion and Power

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Gaseous hydrogen/liquid oxygen turbulent shear coaxial flames were subjected experimentally to both pressure antinode (PAN) and pressure node (PN) transverse acoustic forcing as a function of the gas-to-liquid momentum flux ratio. The response of the flow was recorded using simultaneous high-speed imaging of backlit shadowgraphs and OH chemiluminescence emission. It was observed that a wave amplification mechanism, defined in Sec. III, previously observed for unforced flows, remained present in the forced flows but was modified by the forcing. The response tended to be axisymmetric for PAN forcing, where the pressure fluctuations are symmetric, and asymmetric for PN forcing, where the velocity fluctuations are asymmetric. Additional analyses performed included dynamic mode decomposition (DMD) and an analysis of the OH wave trajectories as a function of time. Beyond the main observation that the wave amplification mechanism remained operative not only for unforced flows but also for both kinds of transverse forcing, secondary observations included a greater relative effect on the flow for PN forcing than for PAN forcing and a reduced general response of the flow to the acoustics at higher momentum flux ratios. The velocity of waves observed in the OH emission were found to depend mainly on the shear layer velocity and not directly on the acoustics.

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Injector-Driven Flame Dynamics in a High-Pressure Multi-Element Oxygen–Hydrogen Rocket Thrust Chamber

Cited by 38 publications

References 30 publications

Experimental Investigation of Self-Excited Combustion Instabilities in a LOX/LNG Rocket Combustor

Experimental Investigation of Self-Excited Combustion Instabilities in a LOX/LNG Rocket Combustor

Experimental Investigation of Injection-Coupled High-Frequency Combustion Instabilities

Transverse Acoustic Forcing of Gaseous Hydrogen/Liquid Oxygen Turbulent Shear Coaxial Flames

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