Flamelet Generated Manifold Simulation of Turbulent Non-Premixed Bluff Body Flames

Verma, Ishan; Yadav, Rakesh; Nakod, Pravin; Sharkey, Patrick; Li, Shaoping; Meeks, Ellen

doi:10.1115/gtindia2019-2525

Cited by 4 publications

(6 citation statements)

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“…The FGM combustion model is widely used in turbulent combustion due to its accurate and efficient. 34,35 The FGM model assumes that the scalar evolution (that is the realized trajectories on the thermochemical manifold) in a turbulent flame can be approximated by the scalar evolution in a laminar flame. Laminar Flamelet and FGM parameterize all species and temperature by a few variables, such as mixture-fraction and reaction-progress, and solve transport equations for these parameters in a 3D CFD simulation.…”

Section: Flamelet Generated Manifold Modelmentioning

confidence: 99%

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Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Zhang

Liu

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The combustion characteristics for a gas turbine (GT) model combustor in air-inlet excitation are studied by Large Eddy Simulation (LES). Time series of heat release rate (HRR) fluctuation is captured during simulation. The precessing vortex core (PVC) structure is shown by pressure iso-surface, and the single/double helix branches of PVC alternately evolve in one forcing cycle. With the rotation of PVC, the high-speed ring zone (HSRZ) is periodically squeezed, and large-scale vortex roll-up results from that. The flame root structure is also significantly affected by PVC, which is one of the reasons for the HRR fluctuation. With the increase of the forcing amplitude, the flame response is divided into three parts. The linear growth zone and secondary rising zone are separated by saturation plateau. The flame dynamics analysis shows that the change of the flame structures and flame front oscillation modes are the apparent mechanism of the nonlinear flame response appearance.

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Section: Flamelet Generated Manifold Modelmentioning

confidence: 99%

“…The FGM combustion model is widely used in turbulent combustion due to its accurate and efficient. 34,35…”

Section: Numerical Approachesmentioning

confidence: 99%

Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Zhang

Liu

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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show abstract

“…A partially premixed combustion model was thus adopted in this work. The flamelet generated manifold (FGM (Verma et al, 2019;Jurić et al, 2021)) model has previously been applied to treat turbulent chemical processes and has been widely used to treat combustion (Ramaekers, 2011;Verma et al, 2019).…”

Section: Turbulent Combustion Modelmentioning

confidence: 99%

“…Meanwhile, mean temperature, density, and species fractions could be determined by looking them up in the PDF table with extremely reduced computational cost. Since the turbulent flames in the present work were predominantly non-premixed, the 1-D laminar counterflow diffusion flame was used to generate diffusion FGMs, and detailed theory can be found in reference (Verma et al, 2019). A detailed reaction mechanism (GRI-Mech 3.0) was used to generate the presumed PDF.…”

Section: Turbulent Combustion Modelmentioning

confidence: 99%

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Three-Dimensional Numerical Analysis of Longitudinal Thermoacoustic Instability in a Single-Element Rocket Combustor

Guo

Ren

et al. 2022

Front. Energy Res.

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This study numerically investigated the thermoacoustic combustion instability characteristics of a scaled rocket combustor based on a hybrid of the Reynolds-averaged Navier–Stokes and large–eddy simulation method. The turbulence–combustion interactions were treated using flamelet generated manifold approach. An unstable case was simulated with detailed reaction mechanisms (GRI-Mech 3.0). The obtained results agree well with experiment data from Purdue University, in terms of pressure oscillations frequency and power spectral density spectrum. The combustion instability mode was identified to be coupled with the first longitudinal acoustic mode of the combustion chamber by dynamic model decomposition method. According to Rayleigh index analysis, the unstable driving source was found to be located near the combustor step, which was further confirmed by time-averaged flow fields. Detailed three-dimensional vortex ring shedding evolutions at the combustor step were tracked with fine time resolution. Results indicate that the combustion instability arises from periodic vortex ring shedding at the combustor step and interacting with the chamber wall. The unburnt reactants were rolled up by the shedding vortex ring, which would not break up until impact with the chamber wall. Therefore, the mixing performance was significantly enhanced, leading to sudden heat release. Consequently, the thermal energy is added to the acoustic field, and the first longitudinal mode is thus reinforced, giving rise to large amplitude axial velocity oscillations which prompt the generation of the new vortex ring. The results of the present investigation will support the design and development of high-performance rocket engines.

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Numerical investigation of the drag reduction effect in turbulent channel flow by superhydrophobic grooved surfaces

Safari,

Saidi,

Salavatidezfouli

et al. 2023

Flow

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Superhydrophobic surfaces (SHSs) are considered to be a promising technology for achieving skin-friction drag reduction. Development of more efficient techniques for simulating the turbulent boundary layer on SHSs continues to be a subject of interest. In this study, numerical simulations were carried out to capture near-wall behaviours due to the effect of the SHS on wall-bounded flows. To achieve this, high- to intermediate-fidelity turbulence models including Reynolds-averaged Navier–Stokes, detached eddy simulation and large eddy simulation were utilized. With regard to slip conditions, the well-known Navier slip velocity method was used over the SHS. For validating the numerical solutions, the slip velocity and skin friction over the SHS were compared with the experimental output. Results showed that the velocity profile and Reynolds stresses on the SHS were comparable to the reported results. Then, the developed models were further extended to investigate the drag reduction effect of SHSs with rectangular grooves. The subsequent results showed that the combination of superhydrophobicity and rectangular grooves led to a better performance with a maximum drag reduction of 46.1%. This is due to the surface slip caused by the SHS and the secondary vortex effect created by the grooves. Our results revealed that Reynolds stresses of the slippery grooved surface were higher than those of the case in which a shear-free condition was employed for the grooved surface. More importantly, the numerical results indicate the previous assumption of the shear-free condition is inaccurate for the geometrically simplified grooved SHSs. Therefore, geometry modifications rather than an overly simplified shear-free boundary condition should be applied in computational fluid dynamics simulations for SHSs with grooves or other complex structures.

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Flamelet Generated Manifold Simulation of Turbulent Non-Premixed Bluff Body Flames

Cited by 4 publications

References 0 publications

Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Three-Dimensional Numerical Analysis of Longitudinal Thermoacoustic Instability in a Single-Element Rocket Combustor

Numerical investigation of the drag reduction effect in turbulent channel flow by superhydrophobic grooved surfaces

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