Experimental investigation of velocity coupling in combustion instability

Ma, Yi-Ping; Moorhem, W. K. Van; Shorthill, R. W.

doi:10.2514/3.23381

Cited by 49 publications

(17 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Threshold effects have been observed in experimental investigations of velocity coupling. Ma et al 19 found a threshold acoustic velocity above which the mean mass ux increased linearly with the Reynolds number of the acoustic uctuations.Below the threshold value, the mean mass ow was approximately constant. It was determined that the increased mass ux is a result of increased heat transfer to the surface after transition to turbulent ow has occurred.…”

Section: Effects Of Noise and Nonlinear Combustionmentioning

confidence: 99%

Influence of random excitations on acoustic instabilities in combustion chambers

Burnley¹,

Culick²

2000

AIAA Journal

View full text Add to dashboard Cite

Although ows in combustors contain considerable noise, arising from several kinds of sources, there is a sound basis for treating organized oscillations as distinct motions. That has been an essential assumption incorporated in virtually all treatments of combustion instabilities. However, certain characteristics of the organized or deterministic motions seem to have the nature of stochastic processes. For example, the amplitudes in limit cycles always exhibit a random character, and even the occurrence of instabilities seems occasionally to possess some statistical features. Analysis of nonlinear coherent motions in the presence of stochastic sources is, therefore, an important part of the theory. We report a few results for organized oscillations in the presence of noise. The most signi cant de ciency is that, because of the low level of current understanding, the stochastic sources of noise are modeled in ad hoc fashion and are not founded on a solid physical basis appropriate to combustion chambers.

show abstract

Section: Effects Of Noise and Nonlinear Combustionmentioning

confidence: 99%

Influence of random excitations on acoustic instabilities in combustion chambers

Burnley¹,

Culick²

2000

AIAA Journal

View full text Add to dashboard Cite

show abstract

“…Moreover, because cold §ow analogs cannot mimic heterogeneous propellants u s,g ( x, t), T s,g ( x, t), M s,g ( x, t), and BS topography BCs, these experiments cannot robustly mimic heterogeneous propellant de §agration sourced §ow ¦elds. Consequently, attempts to idealize cold §ow analog experiments without perspective to heterogeneous propellants£ innate challenges [10] suggest their purpose is to validate idealized §ow ¦eld models rather than to understand application phenomena.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous propellant internal ballistics: criticism and regeneration

Glick

2011

Progress in Propulsion Physics

View full text Add to dashboard Cite

Although heterogeneous propellant and its innately nondeterministic, chemically discrete morphology dominates applications, ballisticcharacterization deterministic time-mean burning rate and acoustic admittance measures£ absence of explicit, nondeterministic information requires homogeneous propellant with a smooth, uniformly regressing burning surface: inadequate boundary conditions for heterogeneous propellant grained applications. The past age overcame this dichotomy with one-dimensional (1D) models and empirical knowledge from numerous, adequately supported motor developments and supplementary experiments. However, current cost and risk constraints inhibit this approach. Moreover, its fundamental science approach is more sensitive to incomplete boundary condition information (garbage-in still equals garbage-out) and more is expected. This work critiques this situation and sketches a path forward based on enhanced ballistic and motor characterizations in the workplace and approximate model and apparatus developments mentored by CSAR DNS capabilities (or equivalent).

show abstract

“…Threshold effects have been observed in experimental investigations of velocity coupling. Ma et al 19 used subliming dry ice to simulate the flow in a solid propellant rocket motor. A piston was used to generate acoustic waves in the chamber.…”

Section: Velocity Couplingmentioning

confidence: 99%

Some Dynamics of Acoustic Oscillations With Nonlinear Combustion and Noise

Burnley¹,

Culick

1997

Int J Energetic Materials Chem Prop

View full text Add to dashboard Cite

The results given in this paper constitute a continuation of progress with nonlinear analysis of coherent oscillations in combustion chambers. We are currently focusing attention on two general problems of nonlinear behavior important to practical applications: the conditions under which a linearly unstable system will execute stable periodic limit cycles; and the conditions under which a linearly stable system is unstable to a sufficiently large disturbance. The first of these is often called 'soft' excitation, or supercritical bifurcation; the second is called 'hard' excitation, 'triggering,' or subcritical bifurcation and is the focus of this paper. Previous works extending over more than a decade have established beyond serious doubt (although no formal proof exists) that nonlinear gasdynamics alone does not contain subcritical bifurcations. The present work has shown that nonlinear combustion alone also does not contain subcritical bifurcations, but the combination of nonlinear gasdynamics and combustion does. Some examples are given for simple models of nonlinear combustion of a solid propellant but the broad conclusion just mentioned is valid for any combustion system. Although flows in combustors contain considerable noise, arising from several kinds of sources, there is sound basis for treating organized oscillations as distinct motions. That has been an essential assumption incorporated in virtually all treatments of combustion instabilities. However, certain characteristics of the organized or deterministic motions seem to have the nature of stochastic processes. For example, the amplitudes in limit cycles always exhibit a random character and even the occurrence of instabilities seems occasionally to possess some statistical features. Analysis of nonlinear coherent motions in the presence of stochastic sources is therefore an important part of the theory. We report here a few results of power spectral densities of acoustic amplitudes in the presence of a sub critical bifurcation associated with nonlinear combustion and gasdynamics.

show abstract

Experimental investigation of velocity coupling in combustion instability

Cited by 49 publications

References 9 publications

Influence of random excitations on acoustic instabilities in combustion chambers

Influence of random excitations on acoustic instabilities in combustion chambers

Heterogeneous propellant internal ballistics: criticism and regeneration

Some Dynamics of Acoustic Oscillations With Nonlinear Combustion and Noise

Contact Info

Product

Resources

About