Two-dimensional simulation of premixed laminar flame at microscale

Turkeli-Ramadan, Zerrin; Sharma, Rajnish N.; Raine, Robert R.

doi:10.1016/j.ces.2015.08.026

Cited by 31 publications

(14 citation statements)

References 44 publications

(59 reference statements)

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“…Computational Fluid Dynamic (CFD) simulations of micro combustion is a relatively recent topic and most studies mainly focus on the effects of combustor size, combustor geometry and operating conditions on the flame shape. The effects of initial mixture temperature and the prediction in terms of species concentration have been recently investigated [9], however none of the above listed publications are related to numerical studies involving combustion stabilized over a flame holder and its interactions with it and with walls. The flame holder allows the flame to be stabilized and controlled, with the additional purpose of preventing flashback and allowing a proper mixing of the fuel air mixture.…”

Section: Type Of Reaction Mechanismmentioning

confidence: 99%

“…The coupling between pressure and velocity is guaranteed by the SIMPLE algorithm and a second order upwind spatial discretization is used. Recently the importance of setting low residual target was proven [9] and in this research they are set to 1 × 10 -6 for continuity, energy and species concentration. In addition the mass flow averaged temperature at the outlet was kept under observation over the iterations.…”

Section: Radiative Heat Transfermentioning

confidence: 99%

“…9 16 species, 25 reactions Effect of combustor size, effect of inlet velocity, effect of slip-wall condition on flame temperature…”

Section: Type Of Reaction Mechanismmentioning

confidence: 99%

“…This dimensionless number is defined as the ratio between residence time of the reactants in the combustion chamber and reaction time of the mixture, thus it indicates whether a reaction is complete or not. It has been experimentally and numerically proven that this problem can be solved by preheating reactants in order to reduce reaction times [6][7][8][9][10][11] and this can be done for example by transferring the heat contained in the combustion products to the incoming unburned mixture without using an external heat source.…”

Section: Introductionmentioning

confidence: 99%

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Premixed combustion of methane–air mixture stabilized over porous medium: A 2D numerical study

Giovannoni

Sharma

Raine

2016

Chemical Engineering Science

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Section: Type Of Reaction Mechanismmentioning

confidence: 99%

Section: Radiative Heat Transfermentioning

confidence: 99%

“…9 16 species, 25 reactions Effect of combustor size, effect of inlet velocity, effect of slip-wall condition on flame temperature…”

Section: Type Of Reaction Mechanismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Premixed combustion of methane–air mixture stabilized over porous medium: A 2D numerical study

Giovannoni

Sharma

Raine

2016

Chemical Engineering Science

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“…In a numerical study of premixed laminar flames in microchannels, Turkeli-Ramadan et al [47] demonstrated and characterised the effect of preheating reactants from 300 K to 800 K for flow velocities between 0.3 and 1 ms −1 . It reinforced the effect of preheating on improving flame stability particularly at high inflow velocities.…”

Section: Wall Conduction Heat Recirculation and Effects On Flame Stamentioning

confidence: 99%

Numerical Modelling of Anisotropic Heat Recirculation in Microcombustors

Chong¹

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The primary motivation for this study is provided by the need for numerical simulations of anisotropic walls of microcombustors which are hypothesised to have a stabilising effect on flame temperatures in microcombustion. A literature review on the topics of wall conduction effects and heat recirculation on flame stability, anisotropic thermal conduction and heat conduction numerical methods are conducted. It is concluded that a finite volume method is most suitable for the desired purpose due to existing code infrastructure in The University of Queensland's own gas dynamics solver Eilmer, for which the capability upgrade is being designed and implemented. An implicit Euler method is selected and the method outlined and implemented using Newton's method. The implementation is verified using observed order of error (OOE). Suitable values for solver tolerances are found specific to the problem tested but also considered indicative of a reasonable range for default values. Homogeneous thermal anisotropy in the form of orthotropy is verified (using OOE via method of manufactured solutions (MMS)) and validated (using an experimental case from Hornbaker [17]). A demonstration of thermal orthotropy on a simplified microcombustor is presented, confirming that significant redirection of heat can be achieved for the purposes of improving flow preheating and reducing external heat losses. Suggestions for future work are provided; in particular, highlighting the need for completion of inhomogeneous anisotropy implementation, full thermal anisotropy (as opposed to orthotropic anisotropy) and temporal lagging.

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Enhancement of biogas/air combustion by hydrogen addition at elevated temperatures

et al. 2019

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Summary In this study, combustion characteristics of various biogas/air mixtures with hydrogen addition at elevated temperatures were experimentally investigated using bunsen burner method. Methane, CH4, was diluted with different concentrations of carbon dioxide, CO2, 30 to 40% by volume, to prepare the biogas for testing. It is followed by the hydrogen, H2, enrichment within the range of 0 to 40% by volume and the temperature elevation of unburned gas till 440 K. Blowoff velocities were measured by lowering the jet velocity until a premixed flame could be stabilized at the nozzle exit, while laminar burning velocities were calculated by analyzing the shape of the directly captured premixed bunsen flames. The results showed that hydrogen had a positive effect on the blowoff velocity for all three fuel samples. Nonlinear growth of the blowoff velocity with hydrogen addition was associated to the dominance of methane‐inhibited hydrogen combustion process. It was also observed that the increase in the initial temperature of the unburned mixture led to a linear increase of the blowoff velocity. Moreover, specific changes in flame structure such as flame height, standoff distance, and the existence of tip opening were attributed to the change in the blowoff velocity. The effect of CO2 content in the mixture was examined with regards to laminar burning velocity for all compositions. The outcome of the experiment showed that the biogas mixture with higher content of CO2 possessed lower values of laminar burning velocity over the wide range of equivalence ratios. A reduced GRI‐Mech 3.0 was used to simulate the combustion of biogas/air mixtures with different compositions using ANSYS Fluent. The numerically simulated stable conical flames were compared with the experimental flames, in terms of flame structure, showing that the reduced GRI‐Mech 3.0 was suitable for modeling the combustion of biogas/air mixtures.

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Two-dimensional simulation of premixed laminar flame at microscale

Cited by 31 publications

References 44 publications

Premixed combustion of methane–air mixture stabilized over porous medium: A 2D numerical study

Premixed combustion of methane–air mixture stabilized over porous medium: A 2D numerical study

Numerical Modelling of Anisotropic Heat Recirculation in Microcombustors

Enhancement of biogas/air combustion by hydrogen addition at elevated temperatures

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