Stability analysis of thermoacoustic interactions in vortex shedding combustors using Poincaré map

Singaravelu, B.; Mariappan, Sathesh

doi:10.1017/jfm.2016.458

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…Our group used the aforementioned Matveev model to obtain analytical predictions of the onset of lock-in (Singaravelu & Mariappan 2016), which compared well with the experimental results of Chakravarthy et al. (2007).…”

Section: Introductionmentioning

confidence: 70%

Lock-in phenomenon of vortex shedding in flows excited with two commensurate frequencies: a theoretical investigation pertaining to combustion instability

Britto

Mariappan

2021

J. Fluid Mech.

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Section: Introductionmentioning

confidence: 70%

Lock-in phenomenon of vortex shedding in flows excited with two commensurate frequencies: a theoretical investigation pertaining to combustion instability

Britto

Mariappan

2021

J. Fluid Mech.

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“…The following subsections discuss their modelling. The presented modelling framework is similar to Matveev & Culick (2003) and the bifurcation analysis follows our previous investigation (Singaravelu & Mariappan 2016).…”

Section: Theoretical Formulationmentioning

confidence: 99%

Self-excited vortex-acoustic lock-in in a bluff body combustor

Britto,

Mariappan

2023

J. Fluid Mech.

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We investigate self-excited vortex-acoustic lock-in in a bluff body combustor. The bluff body not only anchors the flame but also sheds vortices. Mutual interaction between vortex shedding and the combustor acoustic field leads to lock-in. A lower-order model for vortex shedding is coupled to the acoustic equations to obtain a set of discrete dynamical maps, which are then solved numerically. Lock-in is identified when a definite phase relationship between vortex shedding and acoustic field remains unaltered with time. The common frequency during (phase) lock-in is either close to the natural acoustic or vortex shedding frequencies, accordingly termed A- or V-lock-in, respectively. Instability and amplitude suppression occur with most parts of the A- and V-lock-in regions, respectively. Furthermore, we relate the lock-in and pre-lock-in regimes observed in our previous experiments (Singh & Mariappan, Combust. Sci. Technol., 2019, pp. 1–29) to A- and V-lock-in phenomena, respectively. Among the two lock-in phenomena, combustion instability is favoured by $1:1$ A-lock-in, whose boundaries in the parameter space can be obtained from a forced response of the vortex shedding process. Finally, we discuss the bifurcations leading to lock-in.

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“…the formation of the fire core have the greatest impact on the cycle changes; when the CO2 content increases to 20%, the tangent slope of the trajectory dispersion position decreases, the combustion process is difficult, the flame development period is prolonged, and the number of partial combustion and misfire cycles increases significantly; the effect of CO2 on the phase space trajectory dispersion is significantly stronger than N2, the combustion stability of the engine is poor. in an elliptical shape in a small area, indicating that the shale gas engine is operating at the maximum torque, and the phase space of the combustion process exhibits periodic chaotic motion in the Poincaré map of the cross-section ∑XY+ [40]; when the CH4 content is 85%, the distribution range in the X-axis direction is 1.9～2.7MPa, and the distribution range in the Yaxis direction is 0.06 ～0.12MPa/°CA -1 , when the content of CH4 increases, the scatter points move to the lower left corner, the maximum burst pressure and pressure rise rate decrease, the combustion speed decreases, the distribution range is gradually slender, the periodicity weakens, and the combustion stability decreases. When the CH4 content reaches 95%, the distribution range of scattered points in the X-axis direction is 1.75～2.75MPa, and the distribution range of the Y-axis direction is 0.04～0.12MPa/°CA -1 .…”

Section: Phase Space Analysismentioning

confidence: 99%

Nonlinear Dynamic Analysis of Shale Gas Engine Combustion Stability

Liu

Zhang

Zhong

et al. 2021

Preprint

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The traditional analysis method of engine combustion cycle variation is a statistical method based on a small amount of data. In essence, the obtained cycle variation is random data. In order to reveal the dynamic nature of the cyclical changes during the combustion of a shale gas engine, a nonlinear dynamics method was used to study the stability of the combustion process. The motion law of the phase space trajectory is analyzed, the influence of the shale gas composition on the trajectory distribution is analyzed, the return mapping point of the average indicated pressure in the cylinder is discussed. The relationship between adjacent combustion characteristic parameters is studied; the chaotic characteristics of the shale gas engine combustion process are discussed. The results show that during the working process of the shale gas engine, the in-cylinder pressure shows a similar quasi-periodic state in the entire phase space, and the working process has a certain chaotic law; with the increase of the CH4, N2 and CO2 content in the shale gas, the combustion cycle variation increases, and the randomness of the engine working process increases. The phase space trajectory shows a monotonously increasing distribution of Poincaré mapping points on the ∑XY+ section. With the increase of the combustion cycle, the linear relationship of the scattered points gradually increases, and the randomness of the combustion process increases. The return map points of the engine combustion characteristic parameters are distributed in a cluster. When the CH4 content increases, the distribution range of the average indicated pressure return map points increases. With the increase of N2 and CO2 content, abnormal combustion phenomena such as partial combustion or misfire occur during the engine combustion process, the uncertainty of the combustion process increases, and the combustion stability decreases. With the increase of engine speed, the correlation dimension and the maximum Lyapunov exponent increase, the randomness of the combustion process increases, and the chaotic characteristics of the engine working process are obvious; the time series of the cylinder pressure is more sensitive to the content of inert gas. With the increase of N2 and CO2 content in the gas, the correlation dimension and the maximum Lyapunov exponent increase significantly, the complexity of the phase space trajectory increases, and the chaotic characteristics become more obvious.

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Stability analysis of thermoacoustic interactions in vortex shedding combustors using Poincaré map

Cited by 5 publications

References 29 publications

Lock-in phenomenon of vortex shedding in flows excited with two commensurate frequencies: a theoretical investigation pertaining to combustion instability

Lock-in phenomenon of vortex shedding in flows excited with two commensurate frequencies: a theoretical investigation pertaining to combustion instability

Self-excited vortex-acoustic lock-in in a bluff body combustor

Nonlinear Dynamic Analysis of Shale Gas Engine Combustion Stability

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