Coupling of Cryogenic Oxygen–Hydrogen Flames to Longitudinal and Transverse Acoustic Instabilities

Hardi, Justin; Beinke, Scott; Oschwald, Michael; Dally, Bassam B.

doi:10.2514/1.b35003

Cited by 41 publications

(20 citation statements)

References 15 publications

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“…This is exemplified in a book edited by Yang and Anderson [3] , in the monograph written by Culick [12] and in many further investigations. In the recent period, many studies pursue the analytical modeling of the driving mechanisms as for example [13][14][15][16][17][18][19] while new model scale experiments and scaling methods are reported in [20][21][22][23][24][25][26][27][28][29][30][31] . These experiments have provided novel information on the interaction between the combustion region and acoustic modes with much attention focused on transverse modes which are only weakly damped in thrust chambers and are consequently the most dangerous (the detrimental effect of transverse modes was already well recognized during the early period [11,32] ).…”

Section: Introductionmentioning

confidence: 99%

Exploration of combustion instability triggering using Large Eddy Simulation of a multiple injector liquid rocket engine

Urbano

Selle

Staffelbach

et al. 2016

Combustion and Flame

162

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et al.. Exploration of combustion instability triggering using Large Eddy Simulation of a multiple injector Liquid Rocket Engine. Combustion and Flame, Elsevier, 2016, 169, pp. a b s t r a c tThis article explores the possibility of analyzing combustion instabilities in liquid rocket engines by making use of Large Eddy Simulations (LES). Calculations are carried out for a complete small-scale rocket engine, including the injection manifold thrust chamber and nozzle outlet. The engine comprises 42 coaxial injectors feeding the combustion chamber with gaseous hydrogen and liquid oxygen and it operates at supercritical pressures with a maximum thermal power of 80 MW. The objective of the study is to predict the occurrence of transverse high-frequency combustion instabilities by comparing two operating points featuring different levels of acoustic activity. The LES compares favorably with the experiment for the stable load point and exhibits a nonlinearly unstable transverse mode for the experimentally unstable operating condition. A detailed analysis of the instability retrieves the experimental data in terms of spectral features. It is also found that modifications of the flame structures and of the global combustion region configuration have similarities with those observed in recent model scale experiments. It is shown that the overall acoustic activity mainly results from the combination of one transverse and one radial mode of the chamber, which are also strongly coupled with the oxidizer injectors.

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Section: Introductionmentioning

confidence: 99%

Exploration of combustion instability triggering using Large Eddy Simulation of a multiple injector liquid rocket engine

Urbano

Selle

Staffelbach

et al. 2016

Combustion and Flame

162

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“…The 1T resonance mode of the combustion chamber volume is excited as the excitation frequency passes through approximately 4200 Hz. The structures of the acoustic pressure and velocity distributions of the 1T mode were obtained from a numerical modal analysis and detailed in [8]. The 1T mode has a pressure node in the near injector region which means that exciting this mode results in high amplitudes of oscillating acoustic gas motion transverse to the injection axis of the §ames.…”

Section: Figure 1 Illustration Of the Bkh Combustormentioning

confidence: 99%

“…ONERA and DLR both operate research combustors to study the behavior of liquid oxygen (LOx) / hydrogen (H 2 ) rocket §ames under a forced HF acoustic environment, by means of optical diagnostics. The ONERA multiinjector combustor (MIC) [5,6] and the DLR combustor model ¢H£ (BKH) [7,8] both have a rectangular combustion chamber and multiple exhaust nozzles. Under hot-¦re conditions, modulating the exhaust nozzle §ow rate using a toothed wheel, or siren, has proven to be an e¨ective means of exciting transverse acoustic resonance modes of the combustion chamber.…”

Section: Introductionmentioning

confidence: 99%

“…Both BKH and MIC use large windows adapted to perform optical diagnostics in operating conditions representative of real rocket engines, that is, high propellant §owrates and high-pressure in the combustion chamber. Richecoeur et al [9] on the MIC and Hardi et al on the BKH [8] both observed §ame response to the forced acoustic ¦eld by recording the hydroxyl-radical (OH*) signal by means of high-speed cameras. The dynamic response of the §ame submitted to the transverse HF acoustic ¦eld can only be obtained with high-speed diagnostics because the transverse collective displacement of the §ame occurs with the same HF content as the acoustic disturbance.…”

Section: Introductionmentioning

confidence: 99%

“…The technical objective of the collaboration was achieved by combining ONERA and DLR materials: the optical setup resolution of this experiment was improved and the existing database was extended. Regarding the previous studies [7,8], signi¦cant improvements have been made to record the OH* chemiluminescence signal with a better resolution. Indeed, by combining the ONERA high-speed camera and the DLR image intensi¦er, both visible and OH* camera were synchronized at 30 kHz, the shorter exposure time for OH* was set in the middle of the visible exposure time, improving the comparability of instantaneous images.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Flame response to high-frequency oscillations in a cryogenic oxygen/hydrogen rocket combustor

Fdida

Hardi

Kawashima

et al. 2019

Progress in Propulsion Physics – Volume 11

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Experiments presented in this paper were conducted with the BKH rocket combustor at the European Research and Technology Test Facility P8, located at DLR Lampoldshausen. This combustor is dedicated to study the effects of high magnitude instabilities on oxygen/hydrogen flames, created by forcing high-frequency (HF) acoustic resonance of the combustion chamber. This work addresses the need for highly temporally and spatially resolved visualization data, in operating conditions representative of real rocket engines, to better understand the flame response to high amplitude acoustic oscillations. By combining ONERA and DLR materials and techniques, the optical setup of this experiment has been improved to enhance the existing database with more highly resolved OH* imaging to allow detailed response analysis of the flame. OH* imaging is complemented with simultaneous visible imaging and compared to each other here for their ability to capture flame dynamics.

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Experimental Investigation of Injection-Coupled High-Frequency Combustion Instabilities

Armbruster¹,

Hardi²,

Oschwald³

2020

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

Self Cite

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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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Coupling of Cryogenic Oxygen–Hydrogen Flames to Longitudinal and Transverse Acoustic Instabilities

Cited by 41 publications

References 15 publications

Exploration of combustion instability triggering using Large Eddy Simulation of a multiple injector liquid rocket engine

Exploration of combustion instability triggering using Large Eddy Simulation of a multiple injector liquid rocket engine

Flame response to high-frequency oscillations in a cryogenic oxygen/hydrogen rocket combustor

Experimental Investigation of Injection-Coupled High-Frequency Combustion Instabilities

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