combustion instability

combustion instability

[kəm′bəs·chən ‚in·stə′bil·əd·ē]
(aerospace engineering)
Unsteadiness or abnormality in the combustion of fuel, as may occur in a rocket engine.
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This information will also allow to improve the current alumina-radiation modelling and will contribute to understand the combustion instability problem by providing with one of the needed boundary conditions for the CFD: the conditions at the throat.
Taken together, this information will populate a database that will prove useful for diagnosing and solving future combustion instability problems.
If a tap causes a panel to ring, it is probable that a combustion instability will occur at the ringing frequency.
Combustion instability refers to damaging pressure oscillations associated with oscillations in the combustion heat release rate.
The Advanced Liquid Rocket Engine Stability Technology - High Fidelity Model (ALREST-HFM) will be designed to improve the prediction of combustion instability using a combination of advanced algorithms and Computation Fluid Dynamics (CFD).
This collection, translated from the 1999 Russian edition, includes accounts of significant work on facets of combustion instability, including low frequency oscillations in liquid rocket combustion chambers, phenomenological models of the combustion process, the acoustic response of the combustion chamber, high frequency (acoustic) oscillations in a combustion chamber, nonlinear effects, application of the frequency-response method for studying the dynamical properties of the combustion zone, the stability of combustion of fuel drops in a flow of gaseous oxidizer, and bifurcations of steady combustion regimes and their effect on the onset of high-frequency oscillations.
Pulse combustion is the consequence of a combustion instability that is driven into resonance by the geometry of the burner.
Table 4 compares the combustion instability frequencies identified using the mixture flow and equivalence ratio models to the frequencies that were measured.
Combustion instability is caused by a two-way coupling between unsteady combustion and acoustic waves - the large pressure oscillations that result can cause substantial mechanical damage.
An unbalanced engine can cause any of the following conditions: detonation, lower load carrying capability, increased emissions, increased fuel consumption, combustion instability, cylinder wear, piston ring wear, piston ring blow-by, carbon buildup in the ports, excessive frame vibration, foundation issues, bearing failures, and a general increase of engine and support equipment wear.
Examples of specific topics include fast calculation of direct fire trajectories taking the earth's rotation into account, an aerodynamic model for projectile flight simulation using unsteady time accurate computational fluid dynamic results, suppression of axial combustion instability in solid rocket motors, stochastic study of 60-mm gun-projectile responses, a method to increase the tip velocity of a shaped charge jet using a hollow cavity, offshore platforms survivability from underwater explosions, scalable parallel computation of explosively formed penetrators, data mining in military systems, and analysis of weapon systems protecting military camps against mortar fire.