Measurement of Linear Growth of Self-Excited Instabilities in an Idealized Rocket Combustor

Orth, Michael R.; Vodney, Chris; Liu, Thomas T.; Hallum, W. Zach; Pourpoint, Timothée L.; Anderson, William E.

doi:10.2514/6.2018-1185

Cited by 14 publications

(3 citation statements)

References 5 publications

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“…1). This combustor is an evolution of combustors designed to excite transverse mode instabilities [27]. The reactant mixture comprises of gaseous oxygen preheated to 620 K in a hydrogen-fed preburner, and methane (at 297 K).…”

Section: Experimental Configurationmentioning

confidence: 99%

“…In the rest of the paper, we refer to the photomultiplier measurement and the high speed CH* chemiluminescence images as CH* intensity oscillations and local CH* intensity oscillations, respectively. Further details of the geometry of the experimental rig, the operating conditions, hardware and the measurement techniques can be found in Orth et al [27].…”

Section: Experimental Configurationmentioning

confidence: 99%

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Coupled interaction between acoustics and unsteady flame dynamics during the transition to thermoacoustic instability in a multi-element rocket combustor

Kasthuri,

Pawar,

Gejji

et al. 2021

Preprint

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Rocket engine combustors are prone to transverse instabilities that are characterized by large amplitude high frequency oscillations in the acoustic pressure and the heat release rate. In this work, we study the coupled interaction between the acoustic pressure and the CH* intensity (representative of heat release rate) oscillations in a 2D multi-element self-excited model rocket combustor during the transition from a stable state to thermoacoustic instability through intermittency. We show the emergence of synchronization between these oscillations from desynchronization through intermittent phase synchronization during the onset of thermoacoustic instability. We find substantial evidence that the intensities of the jet flames close to the end wall is higher than that observed near the center of the combustor as a result of its strong coupling to the local acoustic field. Using concepts from recurrence theory, we distinguish the type of synchronization between the acoustic pressure and the CH* intensity oscillations at the end wall and the center of the combustor during thermoacoustic instability. Analyzing the local CH* intensity oscillations, we observe that the longitudinally propagating jet flames experience substantial transverse displacement with flame merging effects during thermoacoustic instability. Furthermore, we differentiate the interaction of the jet flames with the shock wave during intermittency and thermoacoustic instability at both the end wall and the center of the combustor. We also discerned the change from stochastic to deterministic nature in the local CH* intensity oscillations during the transition to thermoacoustic instability. Our results demonstrate that only the first few transverse modes contribute to the generation of acoustic power from the reacting flow, in spite of the pressure oscillations featuring several harmonics. The insights gained from such coupled analysis during the transition from stable state to thermoacoustic instability can be leveraged to aid modeling efforts of thermoacoustic instability in rocket engines with multiple injectors.

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Section: Experimental Configurationmentioning

confidence: 99%

Section: Experimental Configurationmentioning

confidence: 99%

Coupled interaction between acoustics and unsteady flame dynamics during the transition to thermoacoustic instability in a multi-element rocket combustor

Kasthuri,

Pawar,

Gejji

et al. 2021

Preprint

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“…The results indicated that combustion instability was associated with periodic vortex shedding. Subsequently, a seven-element (Pomeroy and Anderson, 2016;Popov and Sirignano, 2016) and a nine-element (Orth et al, 2018;Gejji et al, 2020) sub-scale rocket combustor was designed to boost self-excited transverse instabilities. Indepth numerical simulations (Tudisco et al, 2016;Harvazinski et al, 2019) based on the experimental setup were performed.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Tangential Combustion Instability Modes in a LOX/Kerosene Liquid Rocket Engine Based on OpenFOAM

Guo

Ren

et al. 2022

Front. Energy Res.

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Self-excited high frequency combustion instability (HFCI) of first-order tangential (1T) mode was observed in a staged-combustion LOX/Kerosene liquid rocket engine numerically. Two different kinds of 1T patterns, standing wave mode and traveling wave mode, were captured in the present work. In the nominal operation condition, the ratio of oxygen-to-fuel (O/F) was 2.5. Propellant was evenly distributed in all injectors and no HFCI occurred. The chamber pressure obtained from the numerical simulation and experiment showed a good agreement, which validated the numerical model. When the mass flow of fuel for two injectors was modified, severe HFCI occurred. The pressure wave node was located at a fixed diameter, showing a 1T standing wave mode. As the O/F was set 4.4 and the propellant distribution was completely uniform, the numerical result yielded a 1T wave node featured a spinning behavior, which was a traveling 1T wave mode. Once the HFCI arose, no matter what standing mode or spinning mode, the pressure and heat release oscillated totally in phase temporally and coupled spatially. The heat release from combustion was fed into the resonant acoustic mode. This was the thermoacoustic coupling process that maintained the HFCI.

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Low-order modeling approach for the prediction of transverse combustion instabilities in multi-injector engines

Zolla,

Montanari,

D’Alessandro

et al. 2024

CEAS Space J

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This paper addresses the prediction of spontaneous self-sustained transverse combustion instabilities in multi-injector engines using a multi-dimensional non-linear low-order Eulerian model. The approach utilizes a physically aware response function that directly links pressure oscillations to fuel mass flow rate, independent of external data. This enables accurate capture of the behavior of shear coaxial injectors that have been proven to show a peculiar dynamics of cyclic fuel accumulation and release in response to acoustic waves. A NASA test case is employed as a reference, and a comprehensive analysis is conducted to investigate the behavior of the model. Firstly, a preliminary analysis is performed within a quasi-one-dimensional framework for a reduced single-injector configuration. This analysis provides insights into the influence of key parameters on the instability onset. Subsequently, the full-scale geometry is considered in a multi-dimensional framework, and the low-order solver is employed to analyze the thermo-acoustic behavior of the engine. The model successfully captures the instability dynamics, including temporal evolution, dominant frequency, and mode shapes. Sensitivity analyses are conducted to examine the impact of the model free parameters on the unstable modes. Additionally, the effect of introducing baffles as damping devices within the combustion chamber is investigated. The results highlight the model predictive capabilities and its potential for guiding the design and optimization of liquid rocket engines.

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Measurement of Linear Growth of Self-Excited Instabilities in an Idealized Rocket Combustor

Cited by 14 publications

References 5 publications

Coupled interaction between acoustics and unsteady flame dynamics during the transition to thermoacoustic instability in a multi-element rocket combustor

Coupled interaction between acoustics and unsteady flame dynamics during the transition to thermoacoustic instability in a multi-element rocket combustor

Analysis of Tangential Combustion Instability Modes in a LOX/Kerosene Liquid Rocket Engine Based on OpenFOAM

Low-order modeling approach for the prediction of transverse combustion instabilities in multi-injector engines

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