Impact of Infinite Thin Flame Approach on the Evaluation of Flame Speed using Spherically Expanding Flames

Zhang, Feichi; Baust, Tobias M.; Zirwes, Thorsten; Denev, Jordan A.; Habisreuther, Peter; Zarzalis, Nikolaos; Bockhorn, Henning

doi:10.1002/ente.201600573

Cited by 13 publications

(3 citation statements)

References 42 publications

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“…This dataset was compared against asymptotic theory [28] showing good agreement with the reference data. It is further noted that the DC framework was validated against experimental data where only a slight under prediction of the consumption speed was observed [29]. The computational domain is a two-dimensional, axisymmetric wedge with a radius of R = 8 cm.…”

Section: Numerical Setupmentioning

confidence: 97%

Flamelet modeling of thermo-diffusively unstable hydrogen-air flames

Böttler,

Lulic,

Steinhausen

et al. 2023

Preprint

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In order to reduce CO2 emissions, hydrogen combustion has become increasingly relevant for technical applications. In this context, lean H2-air flames show promising features but, among other characteristics, they tend to exhibit thermo-diffusive instabilities. The formation of cellular structures associated with these instabilities leads to an increased flame surface area which further promotes the flame propagation speed, an important reference quantity for design, control, and safe operation of technical combustors. While many studies have addressed the physical phenomena of intrinsic flame instabilities in the past, there is also a demand to predict such flame characteristics with reduced-order models to allow computationally efficient simulations. In this work, a H2-air spherical expanding flame, which exhibits thermo-diffusive instabilities, is studied with flamelet-based modeling approaches both in a-priori and a-posteriori manner. A recently proposed Flamelet/Progress Variable (FPV) model, with a manifold based on unstretched planar flames, and a novel FPV approach, which takes into account a large curvature variation in the tabulated manifold, are compared to detailed chemistry (DC) calculations. Both flamelet approaches account for differential diffusion utilizing a coupling strategy which is based on the transport of major species instead of transporting the manifold control variables. First, both FPV approaches are assessed in terms of an a-priori test with the DC reference dataset. Thereafter, the a-posteriori assessment contains two parts: a linear stability analysis of perturbed planar flames and the simulation of the spherical expanding flame. Both FPV models are systematically analyzed considering global and local flame properties in comparison to the DC reference data. It is shown that the new FPV model, incorporating large curvature variations in the manifold, leads to improved predictions for the microstructure of the corrugated flame front and the formation of cellular structures, while global flame properties are reasonably well reproduced by both models.

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Section: Numerical Setupmentioning

confidence: 97%

Flamelet modeling of thermo-diffusively unstable hydrogen-air flames

Böttler,

Lulic,

Steinhausen

et al. 2023

Preprint

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“…The details are given below and further information can be found in [4,5,6,7,8,9]. The solver has thus far been validated and used in a number of works [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27].…”

Section: Numerical Implementationmentioning

confidence: 99%

Implementation and Validation of a Computationally Efficient DNS Solver for Reacting Flows in OpenFOAM

Zirwes¹,

Zhang²,

Habisreuther³

et al. 2021

14th WCCM-ECCOMAS Congress

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To meet future climate goals, the efficiency of combustion devices has to be increased. This requires a better understanding of the underlying physics. The simulation of turbulent flames is a challenge because of the multi-scale nature of combustion processes: relevant length scales span over five orders of magnitude and time scales over more than ten. Because of this, the direct numerical simulation (DNS) of turbulent flames is only possible on large supercomputers. A DNS solver for chemically reacting flows implemented in the open-source framework Open-FOAM is presented. The thermo-chemical library Cantera is used to compute detailed transport coefficients based on kinetic gas theory. The multi-scale nature of time scales, which are much lower for the combustion chemistry than for the flow, are bridged by an operator splitting approach, which employs the open-source solver Sundials to integrate chemical reaction rates.

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“…[10][11][12][13][14] The research on the propagation properties of turbulent premixed flame is also the focus many scholars' works. [15,16] The common experimental devices of turbulent premixed flame are jet burners, [17][18][19] constant volume burners, [20][21][22] swirl burners, [23,24] and hedge flame burners. [25] Among them, the constant volume bomb can create a homogeneous isotropic turbulent flow field in the bomb, which is very important for analyzing the various characteristics of turbulent premixed flame.…”

Section: Introductionmentioning

confidence: 99%

Effect of Turbulence and Diffusional–Thermal Instability on Hydrogen‐Rich Syngas Turbulent Premixed Flame

Zhang,

Li,

et al. 2023

Energy Tech

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As a kind of fuel with low‐carbon emissions, hydrogen‐rich syngas has a large resource potential and is a promising alternative energy resource. A series of experiments in a constant volume combustion bomb are carried out to investigate the effects of turbulence and diffusional–thermal (DT) instability on a hydrogen‐rich syngas turbulent premixed flame. The flow field in the constant volume combustion bomb is calibrated, and the turbulent flow field's homogeneity and isotropy were investigated. The effects of different speeds of fan (1366–4273 rpm), hydrogen fractions (55%–95%), pressures (1.0–3.0 bar), and equivalence ratios (0.6–1.0) on the hydrogen‐rich syngas turbulent premixed flame are studied. According to the analyses, the flow field in the experimental device exhibits good homogeneous and isotropic characteristics. With the increase of turbulence intensity, equivalence ratio, hydrogen fraction, or pressure, the turbulent flame propagation speed increases gradually. As the hydrogen fraction increases or the equivalence ratio decreases, the effective Lewis number decreases, and the effect of DT instability on the flame increases. The research in this article is crucial for the clean and efficient utilization of hydrogen‐rich syngas and the design of related burners.

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Impact of Infinite Thin Flame Approach on the Evaluation of Flame Speed using Spherically Expanding Flames

Cited by 13 publications

References 42 publications

Flamelet modeling of thermo-diffusively unstable hydrogen-air flames

Flamelet modeling of thermo-diffusively unstable hydrogen-air flames

Implementation and Validation of a Computationally Efficient DNS Solver for Reacting Flows in OpenFOAM

Effect of Turbulence and Diffusional–Thermal Instability on Hydrogen‐Rich Syngas Turbulent Premixed Flame

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