Combustion Instability

Natanzon, M. S.

doi:10.2514/4.866913

Cited by 14 publications

(6 citation statements)

References 18 publications

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“…A second interesting step would be to investigate the compliance of the considered prediction framework with other input-varying delay models, e.g., models of variable time lag appearing in combustion instability studies [17], [27].…”

Section: Discussionmentioning

confidence: 99%

Prediction-Based Stabilization of Linear Systems Subject to Input-Dependent Input Delay of Integral-Type

Bresch‐Pietri

Chauvin

Petit

2014

IEEE Trans. Automat. Contr.

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Abstract-In this paper, it is proved that a predictor-based feedback controller can effectively yield asymptotic convergence for a class of linear systems subject to input-dependent input delay. This class is characterized by the delay being implicitly related to past values of the input via an integral model. This situation is representative of systems where transport phenomena take place, as is frequent in the process industry. The sufficient conditions obtained for asymptotic stabilization bring a local result and require the magnitude of the feedback gain to be consistent with the initial conditions scale. Arguments of proof for this novel result include general Halanay inequalities for delay differential equations and build on recent advances of backstepping techniques for uncertain or varying delay systems.

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Section: Discussionmentioning

confidence: 99%

Prediction-Based Stabilization of Linear Systems Subject to Input-Dependent Input Delay of Integral-Type

Bresch‐Pietri

Chauvin

Petit

2014

IEEE Trans. Automat. Contr.

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“…Entropy waves are not observed in the main combustion chamber of LRs at the optimum ratio between the fuel components [2]. To prevent the amplitude of harmonic self-oscillations from being increased by entropy waves when the fuel flows out of the nozzle of the LR or gas-turbine plant gas generator, it is necessary to realize, in front of the inlet of the flow to the nozzle block, vortex mixing of nonuniformly heated volumes of combustion products [1] for averaging their temperatures, which excludes nonstationary outflow.…”

mentioning

confidence: 64%

“…The numerous experimental and theoretical studies aimed at suppressing self-excited oscillations in the combustion chambers of liquid-fuel rocket engines (LR) [1][2][3] and in the stoves of blast furnaces [4], steam boilers, and other unit heaters [5, 6] make it possible to develop a number of methods for decreasing the amplitude of the above oscillations and ensure stability of the steady-state operation of the above-mentioned devices [7][8]. In LRs, the self-oscillation amplitude of vibrating combustion [2-3] is decreased by introducing into the combustion chamber anti-impulse partitions and by dynamic damping with the help of a Helmholtz resonator.…”

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confidence: 99%

On the problem of decreasing self-oscillations of vibrating combustion

Gotsulenko

2012

J Eng Phys Thermophy

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It has been shown that the self-oscillation amplitude can be decreased by changing the parameters weakening its mechanisms, which can be used for controlling this nonstationary phenomenon.Introduction. The numerous experimental and theoretical studies aimed at suppressing self-excited oscillations in the combustion chambers of liquid-fuel rocket engines (LR) [1][2][3] and in the stoves of blast furnaces [4], steam boilers, and other unit heaters [5, 6] make it possible to develop a number of methods for decreasing the amplitude of the above oscillations and ensure stability of the steady-state operation of the above-mentioned devices [7][8]. In LRs, the self-oscillation amplitude of vibrating combustion [2-3] is decreased by introducing into the combustion chamber anti-impulse partitions and by dynamic damping with the help of a Helmholtz resonator.It has been established experimentally that self-oscillations do not arise in the vertical combustion chamber of the stove of a large cross-section blast furnace under small thermal loads [4]. Moreover, it has been found in experiments that the above chamber produces a stabilizing effect on the flow of combustion products, which shows up as "lengthiness" of combustion. As a result, in each of the chamber cross-sections in which fuel combustion takes place a decrease in the rate of temperature increase occurs. However, there is no theoretical justification of the effects responsible for the decrease in the amplitude of self-oscillations or their complete suppression.A distinguishing feature of vertical combustion chambers of the stoves of blast furnaces and hot-water boilers is their fairly large volume determining their acoustics flexibility C a = V ⁄ c 2 . Therefore, the wave resistance of the above chambers Z = √ ⎯⎯⎯⎯⎯ ⎯ L a ⁄ C a is comparatively small. Because of their small volume, the combustion chambers of LRs feature a rather high wave resistance. Therefore, in such chambers of various designs both harmonic and relaxation self-excited oscillations take place.In conducting full-scale tests of the stoves of blast furnaces [4], it was noticed that the same measures carried out in different combustion chambers can cause different, sometimes contradicting, effects. This is due to the fact that self-oscillations of vibrating combustion arising, as is known, from the retardation of fuel combustion τ (mechanism proposed by L. Crocco) are also excited as a result of heat supply [8].Convective heat supply in the lower segment of the Rijke tube causes through motion of air. In the case where such motion takes place under laminar-flow conditions, along the length of the tube negative viscous and thermal resistances arise [7,9]. Negative resistances that are due to the fuel combustion heat [10] generate an ascending (unstable) branch on the pressure characteristic F(G) of the combustion chamber, which is a new, previously unknown property of vibrating combustion determined by the heat supply [9]. Self-oscillations arising in the oscillatory circuit of a combustion chamber w...

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“…Finally the drive has the ability to control the RPM over a wide frequency range while maintaining a small resolution. For high frequency combustion instability studies, the most dangerous frequencies are in the region from 500 Hz up to 2000 Hz, so the drive motor must be controllable to produce the required RPM range required to generate the desired frequency range (Bazarov et al, 2007;Natanzon, 1981). The hydro-mechanical pulsators are capable of producing both high amplitude and high frequency pulsation.…”

Section: Introductionmentioning

confidence: 98%

Numerical Design Investigation of a Hydro-Mechanical Pulsator for Rocket Motor Injector Dynamics Research

Balasubramanyam

Bazarov

Chen

2010

Engineering Applications of Computational Fluid Mechanics

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Understanding injector dynamics in the presence of strong pressure pulsations in Liquid Fueled Rocket Engines (LFRE) is important due to its strong association with the combustion instability phenomena. Lack of generators of strong periodical pulsations, particularly in the high frequency range, is problematic. To overcome this deficiency, a hydro-mechanical pulsator has been built to generate controlled periodic pressure oscillation, which simulates pressure pulsations in the feed lines of rocket motor injector systems. The present numerical analysis effort utilizes the unsteady Reynolds Averaged Navier-Stokes (URANS) approach, to model the pulsating turbulent flow inside the hydro-mechanical pulsator as a preliminary design study to estimate optimum operating conditions for the proposed experimental study. Numerical results obtained from the study using sliding/deforming grids coupled with a two-layer low-Reynolds number RNG k-ε model indicated that the form of pulsation could be controlled based on the geometry of the orifices of the rotating valve in order to define its main parameters, and in the determination of the optimum geometry for obtaining a sinusoidal harmonic response. The results of the computations to evaluate the effect of varying mass flow rates to examine the influence of change in amplitude and phase characteristics of standard injectors on the boundaries, frequencies and amplitude of high frequency combustion instability are presented in the paper.

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Combustion Instability

Cited by 14 publications

References 18 publications

Prediction-Based Stabilization of Linear Systems Subject to Input-Dependent Input Delay of Integral-Type

Prediction-Based Stabilization of Linear Systems Subject to Input-Dependent Input Delay of Integral-Type

On the problem of decreasing self-oscillations of vibrating combustion

Numerical Design Investigation of a Hydro-Mechanical Pulsator for Rocket Motor Injector Dynamics Research

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