Combustion dynamics in cryogenic rocket engines: Research programme at DLR Lampoldshausen

Hardi, Justin; Traudt, Tobias; Bombardieri, Cristiano; Börner, Michael; Beinke, Scott; Armbruster, Wolfgang; Blanco, P. Nicolas; Tonti, Federica; Suslov, Dmitry; Dally, Bassam B.; Oschwald, Michael

doi:10.1016/j.actaastro.2018.04.002

Cited by 18 publications

(11 citation statements)

References 24 publications

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“…The frequency increase of the 1T mode during forcing could be explained by observing the impact of transverse acoustic velocity on the flame, which improved mixing and reduced the length of the combustion zone significantly, thereby increasing the speed of sound in the upstream part of the chamber where the 1T mode resides. This behavior in BKH has since been reproduced numerically [22,34]. The effect of tangential acoustic oscillations on flame length in BKD for lower amplitude has also been shown numerically [23,35,36].…”

Section: High-amplitude Combustion Instabilitymentioning

confidence: 65%

Wall Heat Loads in a Cryogenic Rocket Thrust Chamber During Thermoacoustic Instabilities

Govaert¹,

Armbruster

Hardi

et al. 2021

Journal of Propulsion and Power

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A subscale, research rocket thrust chamber operating with cryogenic oxygen and hydrogen exhibits self-excited transverse-mode instabilities with amplitudes of more than 80% of the steady combustion chamber pressure (peak-topeak) for some operating conditions. During unstable combustion, an increase in the integral heat flux into the watercooled combustion chamber walls of 20-40% with respect to stable conditions was experienced. A model was derived to predict changes in the axial heat flux profile considering only the dependence of flame length on the amplitude of transverse acoustic oscillations. The model predicts an increase in heat flux in the upstream part of the chamber by up to a factor of 7. This drastic increase is in agreement with past observations of rocket engine failures due to instabilities, in which the structural damage is commonly observed on the faceplate and the walls adjacent to the injection plane. The model also predicts a peak increase in integral heat flux of up to about 25%. While falling short of the peak experimental value of 40%, it nevertheless suggests that flame length is the dominant influence on the distribution of thermal loads in this study. Nomenclature

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Section: High-amplitude Combustion Instabilitymentioning

confidence: 65%

Wall Heat Loads in a Cryogenic Rocket Thrust Chamber During Thermoacoustic Instabilities

Govaert¹,

Armbruster

Hardi

et al. 2021

Journal of Propulsion and Power

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“…This study is performed with experimental data of the research thrust chamber "D" (BKD), which is operated at the European Research and Technology test bench P8 at the DLR Institute of Space Propulsion in Lampoldshausen. BKD has been designed for heat transfer research with regenerative cooling of liquid hydrogen (LH 2 ) at representative conditions of European industrial LOX/H 2 engines, such as Vulcain or Vinci 25,26 . However, the thrust chamber showed self-excited high-frequency combustion instabilities during the first tests for LOX/H 2 combustion.…”

Section: Rocket Thrust Chamber "Bkd"mentioning

confidence: 99%

“…However, the thrust chamber showed self-excited high-frequency combustion instabilities during the first tests for LOX/H 2 combustion. For that reason, BKD has become a valuable platform for the analysis of chamber acoustic phenomena and the underlying coupling mechanism due to the representative geometry and conditions [26][27][28][29][30][31][32] . In later tests, BKD was also used with a similar setup for the investigation of LOX/LNG combustion, which also showed high-frequency combustion instabilities 33 .…”

Section: Rocket Thrust Chamber "Bkd"mentioning

confidence: 99%

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Early Detection of Thermoacoustic Instabilities in a Cryogenic Rocket Thrust Chamber using Combustion Noise Features and Machine Learning

Waxenegger-Wilfing,

Sengupta,

Martin

et al. 2020

Preprint

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Combustion instabilities are particularly problematic for rocket thrust chambers because of their high energy release rates and their operation close to the structural limits. In the last decades, progress has been made in predicting high amplitude combustion instabilities but still, no reliable prediction ability is given. Reliable early warning signals are the main requirement for active combustion control systems. In this paper, we present a data-driven method for the early detection of thermoacoustic instabilities. Recurrence quantification analysis is used to calculate characteristic combustion features from short-length time series of dynamic pressure sensor data. Features like the recurrence rate are used to train support vector machines to detect the onset of an instability a few hundred milliseconds in advance. The performance of the proposed method is investigated on experimental data from a representative LOX/H 2 research thrust chamber. In most cases, the method is able to timely predict two types of thermoacoustic instabilities on test data not used for training. The results are compared with state-of-the-art early warning indicators.High-amplitude pressure oscillations known as combustion instability are an issue for all chemical propulsion systems. Combustion instabilities are particularly problematic for rocket thrust chambers because of their high energy release rates. Especially thermoacoustic oscillations are a major hazard, but difficult to predict. An important question is whether features of combustion noise can be used to construct reliable early warning signals for representative rocket thrust chambers. Among other things, instability precursors are needed for active combustion control systems. In this study, we use recurrence quantification analysis and well-known machine learning models to construct an early warning signal that should be able to predict high-amplitude instabilities a few hundred milliseconds in advance. The performance of the proposed method is investigated on experimental data from a representative LOX/H 2 research thrust chamber. We describe the test case in detail and also evaluate other measures like the Hurst exponent.

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“…It was found that the mass flow rate of the outer injectors was altered by the transverse pressure waves resulting in a sudden heat release, which eventually triggered the transverse combustion instability. A multi-injector cryogenic propellant rocket combustor, characterized by 1T mode self-excited combustion instability, was conducted in the German Aerospace Center (Gröning et al, 2016;Hardi et al, 2016;Armbruster et al, 2020;Klein et al, 2020). Urbano et al (2016) conducted a corresponding high-fidelity calculation, which is a landmark work for its high accuracy and enormous computing load.…”

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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Combustion dynamics in cryogenic rocket engines: Research programme at DLR Lampoldshausen

Cited by 18 publications

References 24 publications

Wall Heat Loads in a Cryogenic Rocket Thrust Chamber During Thermoacoustic Instabilities

Wall Heat Loads in a Cryogenic Rocket Thrust Chamber During Thermoacoustic Instabilities

Early Detection of Thermoacoustic Instabilities in a Cryogenic Rocket Thrust Chamber using Combustion Noise Features and Machine Learning

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

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