Sensitivity Analysis of Bluff-Body Stabilized Premixed Flame Large-Eddy Simulations

Comer, Adam L.; Huang, Cheng; Sardeshmukh, Swanand V.; Rankin, Brent A.; Harvazinski, Matthew E.; Sankaran, Venkateswaran

doi:10.2514/1.b37801

Cited by 8 publications

(3 citation statements)

References 34 publications

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“…The differential operator defines the subgrid-scale viscosity based on the singular values of the velocity gradient tensor . This model has been applied to other stabilized flame cases 56,57 and has shown favorable comparison for the relatively small computation cost particularly in comparison to transport equation based models.…”

Section: Methodsmentioning

confidence: 99%

“…). This model has been applied to other stabilized flame cases 56,57 and has shown favorable comparison for the relatively small computation cost particularly in comparison to transport equation based models. The enthalpy equation unresolved term is closed using the gradient-diffusion model using the turbulent viscosity and a turbulent Prandtl number Pr t approximated as 0.7;…”

Section: Governing Equationsmentioning

confidence: 99%

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Large-eddy simulation and challenges for projection-based reduced-order modeling of a gas turbine model combustor

Arnold-Medabalimi

Huang

Duraisamy

2022

International Journal of Spray and Combustion Dynamics

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Computationally efficient modeling of gas turbine combustion is challenging due to the chaotic multi-scale physics and the complex non-linear interactions between acoustic, hydrodynamic, and chemical processes. A large-eddy simulation, referred to as the full order model (FOM), is performed for a gas turbine model combustor with turbulent combustion effects modeled using a flamelet-based method. Modal analysis reveals a high degree of correlation with averaged and instantaneous high-frequency particle image velocimetry fields. The dynamics of the precessing vortex core is quantitatively characterized using dynamic mode decomposition. The governing equations of the FOM are projected onto a low-dimensional linear manifold to construct a reduced-order model (ROM). A discretely-consistent least squares projection is used to guarantee global stability. The ROM provides an accurate reconstruction of the combustion dynamics within the training region, but faces a significant challenge in future state predictions. This limitation is mainly due to the increased projection error, which in turn is a direct consequence of the highly chaotic nature of the flow field, involving a wide range of dispersed coherent structures. This shortcoming is overcome using an adaptive basis method which yields accurate predictions of dynamics beyond the training region consistent with the FOM. Formal projection-based ROMs have not been applied to a problem of this scale and complexity, and achieving accurate and efficient ROMs is a grand challenge problem. A production-ready ROM method will significantly decrease the computational cost of the flame dynamics as well as the portability of this prediction to smaller-scale computers.

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Section: Methodsmentioning

confidence: 99%

Section: Governing Equationsmentioning

confidence: 99%

Large-eddy simulation and challenges for projection-based reduced-order modeling of a gas turbine model combustor

Arnold-Medabalimi

Huang

Duraisamy

2022

International Journal of Spray and Combustion Dynamics

Self Cite

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“…An effective way to accomplish this is by applying nonreflective boundary conditions through pertinent Riemann invariants. We adopt the formulation that proved to be effective for multi-dimensional reacting flow simulations [57]. It should be mentioned that the ROM training method in Figure 2 requires a level of prior knowledge of the essential physics in the full-system (e.g., acoustics) to ensure that pertinent physics are included in the ROM training.…”

Section: Component-based Reduced-order Model Trainingmentioning

confidence: 99%

Component-Based Reduced Order Modeling of Large-Scale Complex Systems

2022

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Large-scale engineering systems, such as propulsive engines, ship structures, and wind farms, feature complex, multi-scale interactions between multiple physical phenomena. Characterizing the operation and performance of such systems requires detailed computational models. Even with advances in modern computational capabilities, however, high-fidelity (e.g., large eddy) simulations of such a system remain out of reach. In this work, we develop a reduced‐order modeling framework to enable accurate predictions of large-scale systems. We target engineering systems which are difficult to simulate at a high-enough level of fidelity, but are decomposable into different components. These components can be modeled using a combination of strategies, such as reduced-order models (ROM) or reduced-fidelity full-order models (RF-FOM). Component-based training strategies are developed to construct ROMs for each individual component. These ROMs are then integrated to represent the full system. Notably, this approach only requires high-fidelity simulations of a much smaller computational domain. System-level responses are mimicked via external boundary forcing during training. Model reduction is accomplished using model-form preserving least-squares projections with variable transformation (MP-LSVT) (Huang et al., Journal of Computational Physics, 2022, 448: 110742). Predictive capabilities are greatly enhanced by developing adaptive bases which are locally linear in time. The trained ROMs are then coupled and integrated into the framework to model the full large-scale system. We apply the methodology to extremely complex flow physics involving combustion dynamics. With the use of the adaptive basis, the framework is demonstrated to accurately predict local pressure oscillations, time-averaged and RMS fields of target state variables, even with geometric changes.

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Entropy generation and CO2 emission in presence of pulsating oscillations in a bifurcating thermoacoustic combustor with a Helmholtz resonator at off-design conditions

Guan

Becker

Zhao

et al. 2023

Aerospace Science and Technology

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Sensitivity Analysis of Bluff-Body Stabilized Premixed Flame Large-Eddy Simulations

Cited by 8 publications

References 34 publications

Large-eddy simulation and challenges for projection-based reduced-order modeling of a gas turbine model combustor

Large-eddy simulation and challenges for projection-based reduced-order modeling of a gas turbine model combustor

Component-Based Reduced Order Modeling of Large-Scale Complex Systems

Entropy generation and CO2 emission in presence of pulsating oscillations in a bifurcating thermoacoustic combustor with a Helmholtz resonator at off-design conditions

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