Unsteady flame–wall interaction: Impact on CO emission and wall heat flux

Palulli, Rahul; Talei, Mohsen; Gordon, Robert L.

doi:10.1016/j.combustflame.2019.06.012

Cited by 47 publications

(17 citation statements)

References 29 publications

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“…c p is the specific heat capacity per unit mass. The flame front position corresponds to the location of the maximum heat release rate, which is consistent with previous studies (Dabireau et al 2003;Palulli et al 2019).…”

Section: Dimensionless Parameterssupporting

confidence: 90%

Strain Rate Effects on Head-on Quenching of Laminar Premixed Methane-air flames

Luo

Straßacker

Wen

et al. 2020

Flow Turbulence Combust

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Head-on quenching is a canonical configuration for flame-wall interaction. In the present study, the transient process of a laminar premixed flame impinging on a wall is investigated for different strain rates, while previous studies with detailed chemistry and transport focused only on unstrained conditions. Increasing strain rate leads to a reduction in the normalized quenching distance, and an increase in the normalized wall heat flux, both are considered as global flame quantities. Looking more into the local microstructure of the quenching process, CO formation and oxidation near the wall are shifted to higher temperatures under higher strain rates. Further, the local flame structure and the thermochemical state are affected by differential diffusion driven by differences in species' gradients and diffusivities. Quenching leads to increased species' gradients and consequently differential diffusion is amplified near the wall compared to propagating flames. However, this effect is suppressed for increasing strain rates, which is explained in more detail by a source term analysis of the transport equation for the differential diffusion parameter Z HC. Results for the global quantities and the local flame structure show that the impact of the strain rate weakens for higher wall temperatures. Finally, the analyses of the thermo-chemical quantities in the composition space shows that H 2 can be a good parameter to characterize the strain rate both for propagating and quenching flamelet.

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Section: Dimensionless Parameterssupporting

confidence: 90%

Strain Rate Effects on Head-on Quenching of Laminar Premixed Methane-air flames

Luo

Straßacker

Wen

et al. 2020

Flow Turbulence Combust

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“…NTMIX-CHEMKIN [6,7] was used in this study. This FOR-TRAN solver features an eighth-order finite difference scheme to compute the spatial derivatives and a third-order Runge-Kutta method to advance in time.…”

Section: Methodsmentioning

confidence: 99%

Displacement speed characteristics during head-on quenching of premixed methane/air flames

Gupta¹,

Palulli²,

Talei³

et al. 2020

Australasian Fluid Mechanics Conference (AFMC)

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Head-On Quenching (HOQ) occurs when a flame propagates orthogonally towards a wall, and then extinguishes at a distance away from the wall. The flame displacement speed characteristics in a one-dimensional (1D) HOQ configuration are studied using direct numerical simulations (DNSs). A lean (φ = 0.7), premixed methane/air flame at 1 atm pressure with a premixture temperature of 300K propagating towards an inert, isothermal wall is simulated. A 53-species, 325-reactions detailed chemical mechanism, GRI 3.0, is used. The flame displacement speed characteristics over the full range of progress variable values (0 to 1) is analysed for two definitions of progress variables. The progress variable definitions are based on the O 2 and CO 2 mass fractions. The flame displacement speed characteristics during quenching are found to be qualitatively different for different values of progress variable. For small values of progress variable, displacement speed increases monotonically during quenching while an initial decrease in the displacement speed is observed for intermediate values of progress variable, followed by a monotonic increase. Such differences are further investigated by examining the contributions of the diffusion and reaction components of the flame displacement speed. The distance of the progress variable isolines from the wall are found to affect the flame displacement speed characteristics.

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“…2000; Jimenez et al. 2002; Jimenez & Kurdyumov 2017; Jiang, Gordon & Talei 2019; Palulli, Talei & Gordon 2019; Rivera et al. 2019).…”

Section: Direct Numerical Simulation Datasetmentioning

confidence: 99%