Experimental investigation of self-excited combustion instabilities with injection coupling in a cryogenic rocket combustor

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

doi:10.1016/j.actaastro.2018.06.057

Cited by 36 publications

(22 citation statements)

References 12 publications

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“…Phenomena of the instability such as injection, mixing, vaporization and combustion have been studied to elucidate the mechanism of instability. [1][2][3][4][5][6][7][8][9][10][11] It has been revealed that the characteristic time of reaction is significantly shorter than that of the highfrequency instability and that of vaporization is on the same order of magnitude as that of the high-frequency instability. 12) The instability is divided into a transverse mode and a longitudinal mode.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Validation of Off-design Combustion for Liquid-propellant Rocket Engine High-frequency Instability

Kanda

Kikuchi

Kino

2021

Trans. Japan Soc. Aero. S Sci.

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Section: Introductionmentioning

confidence: 99%

“…Table 1 shows the injection and instability conditions of some engines. 3,7,9,10) Typical injection styles (i.e., concentric and impinging injections) and propellants are selected. Áp; pÀp is the peak-to-peak amplitude of pressure change.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of Off-design Combustion for Liquid-propellant Rocket Engine High-frequency Instability

Kanda

Kikuchi

Kino

2021

Trans. Japan Soc. Aero. S Sci.

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“…In the case of the LE-X thrust chamber, coupling of acoustic resonance modes of the LOX injectors with those of the combustion chamber volume was identified as the cause of the instability [3]. This type of driving mechanism for instability, referred to as 'injector coupling', has been reported in the literature for both cryogenic engines [4,5] and sub-scale experiments [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Injector-coupled thermoacoustic instabilities in an experimental LOX-methane rocket combustor during start-up

et al. 2020

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This paper reports the investigation of acoustic combustion instability experienced during repetitive ignition testing of a sub-scale LOX-methane rocket thrust chamber. The occurrence of resonant coupling between the LOX injectors and the combustion chamber acoustic modes was assessed from the experimental data recorded during the highly transient phase of operation from ignition up to around 2 s. A method was developed to model the evolution of acoustic properties in both the combustion chamber and the injectors during the transient period. For the LOX injectors, the Woods equation was used to estimate the speed of sound in the two-phase flow. The models were used to identify the corresponding mode frequencies in the unsteady pressure measurements, and show that the high-amplitude instability occurred when they intersected. Very close coupling of less than 3% frequency difference is required for high amplitudes to be observed. However, the condition was necessary but not sufficient for high amplitudes to be reached. Keywords High-frequency instability • Combustion stability • LOX/CH 4 • Methane List of symbols X Void fraction density A Cross-section area c Speed of sound f Frequency P Static pressure p ′ Dynamic pressure T Temperature t b Begin of phase transition t e End of phase transition ⋅ F Fuel ⋅ g Gaseous phase ⋅ l Liquid phase ⋅ O Oxygen ⋅ CC Combustion chamber ⋅ FM Flow meter ⋅ mlf Two phase ⋅ t Throttle

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“…14,15 In some cases, the amplitude can soar to 75% of the static chamber pressure for rocket combustors. 16 Lieuwen and Zinn 2 investigated one of the mechanisms caused by interactions between combustor pressure oscillations and the fuel supply rates under lean conditions in a low NO X gas turbine, which produces large heat-release oscillations that could drive instabilities. In their analysis, the onset of instability occurs in the following steps: (i) the pressure oscillation at the combustor travels upstream to the fuel injector at the speed of sound, (ii) the pressure oscillation at the fuel injector causes oscillation of the fuel supply rate, (iii) the oscillating fuel supply rate causes oscillation of the equivalence ratio at the fuel injector, (iv) the equivalence ratio fluctuation travels to the combustor at the flow velocity, and (v) finally, the equivalence ratio fluctuation causes oscillations in heat release.…”

Section: Introductionmentioning

confidence: 99%

Effect of ambient pressure oscillation on the primary breakup of cylindrical liquid jet spray

Zhang

Shin

2020

International Journal of Spray and Combustion Dynamics

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The present simulation study investigates the effects of ambient pressure oscillation on cylindrical liquid jet sprays, using the volume of fluid method. The research is motivated by combustion instability in combustion engines, where strong harmonic pressure oscillation can damage internal structures. Oscillating pressure modulates not only the fuel mass flow rate but also the ambient gas density and liquid surface tension, and in liquid sprays, the ambient fluid density and surface tension can have substantial effects on spray breakup. In order to investigate the multiple property changes with ambient pressure oscillation, therefore, a new solver in OpenFOAM is developed. In the solver, liquid mass flow rate, ambient gas density, and liquid surface tension change simultaneously as a result of pressure oscillation. Simulations were conducted at a Reynolds number of 2000 and Weber number over 2000, conditions that are conducive to primary breakup in laminar flows. The simulations show that oscillations in ambient pressure significantly strengthen the surface instability of the liquid ligament, which depends on the surface tension–pressure coefficient, the mean pressure, and the amplitude of oscillation.

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Experimental investigation of self-excited combustion instabilities with injection coupling in a cryogenic rocket combustor

Cited by 36 publications

References 12 publications

Experimental Validation of Off-design Combustion for Liquid-propellant Rocket Engine High-frequency Instability

Experimental Validation of Off-design Combustion for Liquid-propellant Rocket Engine High-frequency Instability

Injector-coupled thermoacoustic instabilities in an experimental LOX-methane rocket combustor during start-up

Effect of ambient pressure oscillation on the primary breakup of cylindrical liquid jet spray

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