Assessing the impact of multicomponent diffusion in direct numerical simulations of premixed, high-Karlovitz, turbulent flames

Fillo, Aaron J.; Schlup, Jason; Blanquart, Guillaume

doi:10.1016/j.combustflame.2020.09.013

Cited by 8 publications

(5 citation statements)

References 44 publications

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“…Moreover, the 13% quantitative difference in peak enstrophy shown in Fig. 3 closely matches the difference in mean turbulent flame speed in these flames shown previously by Fillo et al 32 .…”

Section: B Enstrophy Dynamicssupporting

confidence: 89%

“…Chemical reactions in the hydrogen-air mixture are solved using the nine species, 54 reaction chemistry model from Hong et al [28][29][30] (forward and backward reactions are counted separately). The 3D turbulent flames are simulated using an identical flow configuration as in previous studies 14,20,26,31,32 , and therefore we only provide a brief description here. The computational domain consists of inflow and convective outflow boundary conditions in the streamwise (i.e., x) direction.…”

Section: Simulation Configurationmentioning

confidence: 99%

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Assessing diffusion model impacts on enstrophy and flame structure in turbulent lean premixed flames

Fillo,

Hamlington,

Niemeyer

2021

Preprint

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Diffusive transport of mass occurs at small scales in turbulent premixed flames. As a result, multicomponent mass transport, which is often neglected in direct numerical simulations (DNS) of premixed combustion, has the potential to impact both turbulence and flame characteristics at small scales. In this study, we evaluate these impacts by examining enstrophy dynamics and the internal structure of the flame for lean premixed hydrogen-air combustion, neglecting secondary Soret and Dufour effects. We performed three-dimensional DNS of these flames by implementing the Stefan-Maxwell equations in the code NGA to represent multicomponent mass transport, and we simulated statistically planar lean premixed hydrogen-air flames using both mixture-averaged and multicomponent models. The mixture-averaged model underpredicts the peak enstrophy in the multicomponent simulation by up to 13 % in the flame front. Comparing the enstrophy budgets of these flames, the multicomponent simulation yields larger peak magnitudes compared to the mixtureaveraged simulation in the reaction zone, showing differences of 17 % and 14 % in the normalized vortex stretching and viscous effects terms. In the super-adiabatic regions of the flame, the mixture-averaged model overpredicts the viscous effects by up to 13 %. To assess the effect of these differences on flame structure, we reconstructed the average local internal structure of the turbulent flame through statistical analysis of the scalar gradient field. Based on this analysis, we show that large differences in viscous effects contribute to significant differences in the average local flame structure between the two models.

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Section: B Enstrophy Dynamicssupporting

confidence: 89%

Section: Simulation Configurationmentioning

confidence: 99%

Assessing diffusion model impacts on enstrophy and flame structure in turbulent lean premixed flames

Fillo,

Hamlington,

Niemeyer

2021

Preprint

Self Cite

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show abstract

“…In fact, it is in the analysis of the detail of the flame physics that DNS has been the most successful, specifically when those details cannot be reached by the most advanced experimental tools. The behaviors of thermochemical quantities and scalars in flames [37][38][39] and constitutive relations to calibrate different flame dynamics [40][41][42][43], can easily be identified from DNS. In short, DNS has been shown to be a valuable tool when the roadmap is driven by clear reacting flow physics stumbling block needed clarifications, as shown in recent reviews on the subject [18,[44][45][46][47][48].…”

Section: Tangential Diffusionmentioning

confidence: 99%

“…Some of these simulations are with single-or two-step global chemistry [76,85,87,93,99,103,112,115,128,129,144,145,161,221]. The chemistry of methane has motivated many works [21, 27, 41, 42, 50, 52, 54, 56, 61, 62, 68, 74, 77, 82, 84, 88-90, 92, 93, 96, 97, 101, 103, 107, 110, 113, 114, 118, 119, 123, 133, 134, 138, 145, 155, 156, 163, 169, 176, 182, 184, 189, 207, 211, 217, 220, 222, 223], also hydrogen [32, 38, 43, 60, 69, 70, 78, 79, 81, 90, 95, 97-99, 102, 105, 106, 109, 117, 120, 124, 126, 127, 129, 132, 136, 154, 160, 171, 172, 174, 181-183, 185, 193, 195, 204, 209, 214, 218, 224-229], heavy fuel [37,38,53,66,88,100,108,140,145,151,162,170,180,197,203,221,[230][231][232], syngas [66,114,166,181,212,215,216] and very recently ammonia [97]. M...…”

Section: Tangential Diffusionmentioning

confidence: 99%

Recent developments in DNS of turbulent combustion

Domingo

2023

Proceedings of the Combustion Institute

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“…The figures in this article, as well as the data and plotting scripts necessary to reproduce them, are available openly under the CC-BY license [57].…”

Section: Appendix a Availability Of Materialsmentioning

confidence: 99%

Assessing the impact of multicomponent diffusion in direct numerical simulations of premixed, high-Karlovitz, turbulent flames

Fillo,

Schlup,

Blanquart

et al. 2020

Preprint

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Implementing multicomponent diffusion models in numerical combustion studies is computationally expensive; to reduce cost, numerical simulations commonly use mixture-averaged diffusion treatments or simpler models. However, the accuracy and appropriateness of mixture-averaged diffusion has not been verified for three-dimensional, turbulent, premixed flames. In this study we evaluated the role of multicomponent mass diffusion in premixed, threedimensional high Karlovitz-number hydrogen, n-heptane, and toluene flames, representing a range of fuel Lewis numbers. We also studied a premixed, unstable two-dimensional hydrogen flame due to the importance of diffusion effects in such cases. Our comparison of diffusion flux vectors revealed differences of 10-20 % on average between the mixture-averaged and multicomponent diffusion models, and greater than 40 % in regions of high flame curvature. Overall, however, the mixture-averaged model produces small dif-

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Assessing the impact of multicomponent diffusion in direct numerical simulations of premixed, high-Karlovitz, turbulent flames

Cited by 8 publications

References 44 publications

Assessing diffusion model impacts on enstrophy and flame structure in turbulent lean premixed flames

Assessing diffusion model impacts on enstrophy and flame structure in turbulent lean premixed flames

Recent developments in DNS of turbulent combustion

Assessing the impact of multicomponent diffusion in direct numerical simulations of premixed, high-Karlovitz, turbulent flames

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