Identification and analysis of instability in non-premixed swirling flames using LES

Dinesh, K.K.J. Ranga; Jenkins, Karl W.; Kirkpatrick, M.P.; Malalasekera, Weeratunge

doi:10.1080/13647830903295899

Cited by 15 publications

(2 citation statements)

References 53 publications

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“…Experimental investigations 30,31 are of great help in gaining the preliminary insights on this issue, but deeper understandings are hampered as a result of the measurement limits. Numerical simulations 32–34 seem to be a promising tool in revealing the underlying mechanism by providing more comprehensive flow information. In addition, two‐phase simulations are highly expected to predict the stability of gas core in the axial separator but full of challenges 35–37 considering the flow regime transition in it.…”

Section: Introductionmentioning

confidence: 99%

Review on key issues of an axial gas–liquid separator for ultralow gas content

Yin

Zhang

et al. 2022

AIChE Journal

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The separation of gas and liquid is a topic of general interest in science and engineering, for which tremendous efforts are endeavored to develop separators with high efficiency and reliability. However, when it comes to ultralow gas content, some of the separators fail. A special separator finds the potential herein, which consists of a swirl vane, a swirl chamber and a recovery vane. When the gas–liquid mixture goes through the swirl vane, bubbles will be concentrated into the swirl chamber center and evolved into a gas core. However, two key issues need to be addressed for the axial separator before industrial applications. One issue is that all the bubbles must be captured without exception, that is, the separation efficiency is close to 100%. The other issue is the stability of the gas core, the shape of which is sometimes rectilinear and sometimes spiral. A successful separation relies on the rectilinear shaped gas core. Focused on the two issues above, tremendous experimental, numerical and theoretical investigations have been carried out. In this article, the key challenges and solutions for the two issues are summarized.

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Section: Introductionmentioning

confidence: 99%

Review on key issues of an axial gas–liquid separator for ultralow gas content

Yin

Zhang

et al. 2022

AIChE Journal

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“…Balaji et al / Journal of Energy and Environmental Sustainability, 1 (2016)[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] …”

mentioning

confidence: 99%

Numerical Investigation of Swirling Hydrogen Flames: Effect of Swirl and Fuel Jet in Coherent Structures

Balaji¹,

De²,

De³

2016

JEES

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The present work reports on the numerical investigation of turbulent swirling flames using Large Eddy Simulation (LES) methodology in conjunction with presumed shape PDF (Probability Density Function) based combustion models. The LES with dynamic-smagorinsky eddy viscosity model is used to study the different complex unsteady structures involved in the flow field. Sydney swirl burner, which is considered as a reliable benchmark for numerical studies in swirling flames, is chosen as a test case. Two isothermal and three reacting test cases are considered for the present study. In the isothermal calculations, a precession vortex core is accurately captured. The precession vortex core structures, responsible for the instability in hydrogen-methane reacting cases, are analyzed using different visualization techniques. Phase averaging technique is also used to analyze the different repeated coherent structures responsible for the instability in the flow field.

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Scaling of Flame Describing Functions in Premixed Swirling Flames

Kallifronas

Ahmed

Massey

et al. 2023

Flow Turbulence Combust

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Predicting the response of swirling flames subjected to acoustic perturbations poses significant challenges due to the complex nature of the flow. In this work, the effect of swirl number on the Flame Describing Function (FDF) is explored through a computational study of four bluff-body stabilised premixed flames with swirl numbers ranging between 0.44 and 0.97 and at forcing amplitudes of 7% and 25% of the mean bulk velocity. The LES model used for the simulations is validated by comparing two of those flames to experiments. The comparison is observed to be good with the computations capturing the unforced flow structure, flame height and FDF behaviour. It is found that changes in the swirl number can affect the location of the minima and maxima of the FDF gain in the frequency space. These locations are not affected by changes in the forcing amplitude, but the gain difference between the minima and the maxima is reduced as the forcing amplitude is increased. It is then attempted to scale the FDF using Strouhal numbers based on two different flame length scales. A length scale based on the axial height of the maximum heat release rate per unit length leads to a good collapse of the FDF gain curves. However, it is also observed that flow instabilities present in the flow can affect the FDF scaling leading to an imperfect collapse.

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Identification and analysis of instability in non-premixed swirling flames using LES

Cited by 15 publications

References 53 publications

Review on key issues of an axial gas–liquid separator for ultralow gas content

Review on key issues of an axial gas–liquid separator for ultralow gas content

Numerical Investigation of Swirling Hydrogen Flames: Effect of Swirl and Fuel Jet in Coherent Structures

Scaling of Flame Describing Functions in Premixed Swirling Flames

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