Response of a Gas-Centered Swirl Coaxial Injector to Transverse Instabilities

Pomeroy, Brian; Morgan, Charlotte; Anderson, William A.

doi:10.2514/6.2011-5698

Cited by 9 publications

(4 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Results from similar investigations of transverse mode influence on coaxial injection, for example by Wierman et al 18 , Pomeroy et al 17 , or Sliphorst 8 , suggest that convective transverse motion also prevented isolated extraction of combustion intensity response in those cases. Maximum response amplitudes were observed in the outer lobe regions of single flames, where the transverse motion caused alternating presence and absence of combustion.…”

Section: A Response To Excitation Of the 1t Modementioning

confidence: 88%

“…Whichever type of 'study element' is then located in the centre of the injector face, where transverse acoustic velocity is greatest, can be studied optically through windows. Pomeroy et al 17 studied the unstable 'driving elements' themselves, having placed another GCSC element in the study-element location. High-speed backlit shadowgraph and CH* emission imagery were recorded simultaneously to study combustion emission distribution and phase.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Coupling Behaviour of LOx/H2 Flames to Longitudinal and Transverse Acoustic Instabilities

Hardi¹,

Beinke²,

Oschwald³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

View full text Add to dashboard Cite

A rectangular combustor with acoustic forcing was used to study flame-acoustic interaction under injection conditions which are representative of industrial rocket engines. Hot-fire tests using liquid oxygen and gaseous hydrogen were conducted at pressures of 40 and 60 bar, which are sub-and supercritical conditions respectively for oxygen. To our knowledge, acoustic forcing has never before been conducted at pressures this high in an oxygen-hydrogen system. Examined samples of hydroxyl-radical emission imaging, collected using a high-speed camera during periods of forced acoustic resonance, show significant response in the multi-injection element flame. Transverse acoustic velocity causes shortening of the flame, concentrating heat release near the injection plane. Fluctuating acoustic pressure causes in-phase fluctuation of the emission intensity. Based on these observations, a theorized flame-acoustic coupling mechanism is offered as an explanation for how naturally occurring high frequency combustion instabilities are sustained in real rocket engines. Nomenclature c = bulk sound speed in combustion chamber I = OH* emission intensity I' = fluctuating component of OH* emission intensity Ī = time averaged OH* emission intensity J = injection momentum flux ratio N = response factor ω = acoustic frequency p' = acoustic pressure amplitude P cc = combustion chamber pressure p 0 = eigenmode solution acoustic pressure distribution R = Rayleigh index ROF = oxidizer-to-fuel mixture ratio ρ = bulk density in combustion chamber u' = acoustic (particle) velocity VR = injection velocity ratio

show abstract

Section: A Response To Excitation Of the 1t Modementioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Coupling Behaviour of LOx/H2 Flames to Longitudinal and Transverse Acoustic Instabilities

Hardi¹,

Beinke²,

Oschwald³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

View full text Add to dashboard Cite

show abstract

“…Soller et al [11] conducted a hot fire test in a thruster chamber with several coaxial swirl injectors under the condition of chamber pressures in the range of 4.0 MPa to 8.5 MPa and mixture ratios between 2.4 and 3.5, and the effects of the injector's parameters on the combustion instability were observed. Pomeroy et al [12,13] studied the response of combustion in a gas-centered swirl coaxial injector to high-amplitude, high-frequency, and transverse-mode pressure oscillation by using a high-speed camera. Kim and Heister [14] developed a homogeneous two-phase flow model to assess hydrodynamic instabilities of coaxial injectors, in which effects of the density ratio, gas-liquid velocity ratio, sheet thickness, channel length, and Reynolds number on such instabilities were discussed.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Acoustic Properties of Thruster Chamber with Coaxial Injectors and Plenum Chamber

Gao

Qin

Zhang

2020

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

Based on the URANS equation, a numerical simulation is carried out for acoustic properties of the thruster chamber with coaxial injectors and plenum chamber in a liquid rocket engine. Pressure oscillations with multiacoustic modes are successfully excited in the chamber by using the constant volume bomb method. FFT analysis is applied to obtain the acoustic properties of eigenfrequencies, power amplitudes, and damping rates for each excited acoustic mode. Compared with the acoustic properties in the model chamber with and without an injector as well as with and without the plenum chamber, it can be found that the injector with one open end and one half-open end still can work as a quarter-wave resonator. The power amplitudes of the acoustic mode can be suppressed significantly when its eigenfrequency is close to the tuning frequency of the injector, which is achieved by Cutting down the pressure Peak and Raising up the pressure Trough (CPRT). Compared with the acoustic properties in the model chamber with and without the plenum chamber, it can be found that 1L acoustic pressure oscillation is inhibited completely by the plenum chamber and other acoustic pressure oscillations are also suppressed in a different extent. The injector and plenum chamber have a little effect on the eigenfrequencies and damping rate of each acoustic mode. For multimode pressure oscillation, it is better for tuning frequency of the injector closing to the lower eigenfrequency acoustic mode, which will be effective for suppression of these multiacoustic modes simultaneously.

show abstract

“…[10][11][12] Anderson's group has also been exploring transverse instabilities using a linear array of injectors with the outer-most injectors designed to be unstable to drive a transverse mode in the combustion chamber. [13][14][15] These efforts have focused on swirl-coaxial injectors operating with various oxidizer/hydrocarbon combinations. High-amplitude pressure fluctuations were observed for these experiments.…”

Section: Introductionmentioning

confidence: 99%

The Response of Cryogenic H2/O2 Coaxial Jet Flames to Acoustic Disturbances

Forliti

Badakhshan

Wegener

et al. 2015

53rd AIAA Aerospace Sciences Meeting

View full text Add to dashboard Cite

An experimental study has been conducted to explore the coupling between a coaxial gaseous hydrogen / liquid oxygen jet flame and transverse acoustic perturbations. A variety of chamber conditions including acoustic frequency, amplitude, and the location of the pressure node / antinode with respect to the flame were examined. The flame response was documented using high-speed imaging including backlit visualization and unfiltered chemiluminescence. Dynamic mode decomposition was used to isolate the spatial structure of the flame response at the forcing frequency. The results indicate that the flame response to forcing is qualitatively similar to previous results of nonreacting coaxial jet flows; the pressure node forcing appears to generate in-plane flapping of the flame while pressure antinode forcing induces a helical structure in the flame.

show abstract

Response of a Gas-Centered Swirl Coaxial Injector to Transverse Instabilities

Cited by 9 publications

References 14 publications

Coupling Behaviour of LOx/H2 Flames to Longitudinal and Transverse Acoustic Instabilities

Coupling Behaviour of LOx/H2 Flames to Longitudinal and Transverse Acoustic Instabilities

Investigation on Acoustic Properties of Thruster Chamber with Coaxial Injectors and Plenum Chamber

The Response of Cryogenic H2/O2 Coaxial Jet Flames to Acoustic Disturbances

Contact Info

Product

Resources

About