Numerical study of methane/air jet flame in vitiated co-flow using tabulated detailed chemistry

This numerical study deals with a premixed ethylene-air jet at 300 K injected into a hot vitiated crossflow at 1500 K and atmospheric pressure. The reactive jet in crossflow (RJICF) was simulated with compressible 3-D large eddy simulations (LES) with an analytically reduced chemistry (ARC) mechanism and the dynamic thickened flame (DTF) model. ARC enables simulations of mixed combustion modes, such as autoignition and flame propagation, that are both present in this RJICF. 0-D and 1-D simulations provide a comparison with excellent agreement between ARC and detailed chemistry in terms of autoignition time and laminar flame speed. The effect of the DTF model on autoignition was investigated for varying species compositions and mesh sizes. Comparisons between LES and experiments are in good agreement for average velocity distributions and jet trajectories; LES remarkably capture experimentally observed flame dynamics. An analysis of the simulated RJICF shows that the leeward propagating flame has a stable flame root close to the jet exit. The lifted windward flame, on the contrary, is anchored in an intermittent fashion due to autoignition flame stabilization. The windward flame base convects downstream and is “brought back” by autoignition alternately. These autoignition events occur close to a thin layer that is associated with radical build-up and that stretches down to the jet exit.

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Large Eddy Simulation of a Premixed Flame in Hot Vitiated Crossflow With Analytically Reduced Chemistry

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4041205 ◽

2018 ◽

Vol 141 (3) ◽

Cited By ~ 4

Author(s):

Oliver Schulz ◽

Nicolas Noiray

Keyword(s):

Laminar Flame ◽

Numerical Study ◽

Flame Stabilization ◽

Detailed Chemistry ◽

Eddy Simulation ◽

Jet In Crossflow ◽

Air Jet ◽

Reduced Chemistry ◽

Large Eddy ◽

Stable Flame

This numerical study deals with a premixed ethylene–air jet at 300 K injected into a hot vitiated crossflow at 1500 K and atmospheric pressure. The reactive jet in crossflow (RJICF) was simulated with compressible 3D large eddy simulations (LES) with an analytically reduced chemistry (ARC) mechanism and the dynamic thickened flame (DTF) model. ARC enables simulations of mixed combustion modes, such as autoignition and flame propagation, that are both present in this RJICF. 0D and 1D simulations provide a comparison with excellent agreement between ARC and detailed chemistry in terms of autoignition time and laminar flame speed. The effect of the DTF model on autoignition was investigated for varying species compositions and mesh sizes. Comparisons between LES and experiments are in good agreement for average velocity distributions and jet trajectories; LES remarkably capture experimentally observed flame dynamics. An analysis of the simulated RJICF shows that the leeward propagating flame has a stable flame root close to the jet exit. The lifted windward flame, on the contrary, is anchored in an intermittent fashion due to autoignition flame stabilization. The windward flame base convects downstream and is “brought back” by autoignition alternately. These autoignition events occur close to a thin layer that is associated with radical build-up and that stretches down to the jet exit.

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MODELING OF A TURBULENT ETHYLENE/AIR JET FLAME USING HYBRID FINITE VOLUME/MONTE CARLO METHODS

Computational Thermal Sciences An International Journal ◽

10.1615/computthermalscien.v1.i1.20 ◽

2009 ◽

Vol 1 (1) ◽

pp. 37-53 ◽

Cited By ~ 6

Author(s):

Ranjan S. Mehta ◽

Anquan Wang ◽

Michael F. Modest ◽

Daniel C. Haworth

Keyword(s):

Monte Carlo ◽

Finite Volume ◽

Monte Carlo Methods ◽

Jet Flame ◽

Air Jet

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Experimental and Numerical Study on Grinding Temperature during Surface Grinding with Different Cooling Methods

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.416.514 ◽

2009 ◽

Vol 416 ◽

pp. 514-518 ◽

Cited By ~ 1

Author(s):

Qing Long An ◽

Yu Can Fu ◽

Jiu Hua Xu

Keyword(s):

Numerical Study ◽

Specific Energy Consumption ◽

Ground Surface ◽

Numerical Results ◽

Surface Grinding ◽

Grinding Temperature ◽

Air Jet ◽

The Difference ◽

High Specific Energy ◽

Cooling Methods

Grinding, characterized by its high specific energy consumption, may generate high grinding zone temperature. These can cause thermal damage to the ground surface and poor surface integrity, especially in the grinding of difficult-to-machine materials. In this paper, experimental and fem study on grinding temperature during surface grinding of Ti-6Al-4V with different cooling methods. A comparison between the experimental and numerical results is made. It is indicated that the difference between experimental and numerical results is below 15% and the numerical results can be considered reliable. Grinding temperature can be more effectively reduced with CPMJ than that with cold air jet and flood cooling method.

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Numerical study of flame structure in the mild combustion regime

Thermal Science ◽

10.2298/tsci120522091m ◽

2015 ◽

Vol 19 (1) ◽

pp. 21-34 ◽

Cited By ~ 7

Author(s):

Amir Mardani ◽

Sadegh Tabejamaat

Keyword(s):

Fuel Injection ◽

Numerical Study ◽

Flame Structure ◽

Combustion Regime ◽

Low Oxygen ◽

Mixing Rate ◽

Jet Flame ◽

Reduced Mechanism ◽

Mild Combustion ◽

O2 Concentration

In this paper, turbulent non-premixed CH4+H2 jet flame issuing into a hot and diluted co-flow air is studied numerically. This flame is under condition of the moderate or intense low-oxygen dilution (MILD) combustion regime and related to published experimental data. The modelling is carried out using the EDC model to describe turbulence-chemistry interaction. The DRM-22 reduced mechanism and the GRI2.11 full mechanism are used to represent the chemical reactions of H2/methane jet flame. The flame structure for various O2 levels and jet Reynolds numbers are investigated. The results show that the flame entrainment increases by a decrease in O2 concentration at air side or jet Reynolds number. Local extinction is seen in the upstream and close to the fuel injection nozzle at the shear layer. It leads to the higher flame entertainment in MILD regime. The turbulence kinetic energy decay at centre line of jet decreases by an increase in O2 concentration at hot Co-flow. Also, increase in jet Reynolds or O2 level increases the mixing rate and rate of reactions.

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Influence of Burner Material, Tip Temperature, and Geometrical Flame Configuration on Flashback Propensity of H2-Air Jet Flames

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4025359 ◽

2013 ◽

Vol 136 (2) ◽

Cited By ~ 13

Author(s):

Zhixuan Duan ◽

Brendan Shaffer ◽

Vincent McDonell ◽

Georg Baumgartner ◽

Thomas Sattelmayer

Keyword(s):

Jet Flames ◽

Comprehensive Overview ◽

High Hydrogen ◽

Jet Flame ◽

Practical Applications ◽

Geometric Configurations ◽

Air Jet ◽

Low Emission ◽

Flame Burner ◽

Negative Impacts

Flashback is a key operability issue for low emission premixed combustion systems operated on high hydrogen content fuels. Previous work investigated fuel composition impacts on flashback propensity and found that burner tip temperature was important in correlating flashback data in premixed jet flames. An enclosure around the jet flame was found to enhance the flame–burner rim interaction. The present study further addresses these issues using a jet burner with various geometric configurations and interchangeable materials. Systematic studies addressing the quantitative influence of various parameters such as tip temperature, burner material, enclosure size, and burner diameter on flashback propensity were carried out. A comprehensive overview of the flashback limits for all conditions tested in the current study as well as those published previously is given. The collective results indicate that the burner materials, tip temperature, and flame confinement play significant roles for flashback propensity and thus help explain previous scatter in flashback data. Furthermore, the present work indicates that the upstream flame propagation during flashback is affected by the burner material. The material with lower thermal conductivity yields larger flashback propensity but slower flame regression inside the tube. These observations can be potentially exploited to minimize the negative impacts of flashback in practical applications.

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Effects of strain rate and CO2 on no formation in CH4/N2/O2 counter-flow diffusion flames

Thermal Science ◽

10.2298/tsci170922062r ◽

2018 ◽

Vol 22 (Suppl. 2) ◽

pp. 769-776

Author(s):

Fei Ren ◽

Longkai Xiang ◽

Huaqiang Chu ◽

Weiwei Han

Keyword(s):

Strain Rate ◽

Diffusion Flames ◽

Numerical Study ◽

Flame Temperature ◽

Co2 Concentration ◽

No Production ◽

Counter Flow ◽

Detailed Chemistry ◽

No Formation ◽

Key Factor

The reduction of nitrogen oxides in the high temperature flame is the key factor affecting the oxygen-enriched combustion performance. A numerical study using an OPPDIF code with detailed chemistry mechanism GRI 3.0 was carried out to focus on the effect of strain rate (25-130 s?1) and CO2 addition (0-0.59) on the oxidizer side on NO emission in CH4 / N2 / O2 counter-flow diffusion flame. The mole fraction profiles of flame structures, NO, NO2 and some selected radicals (H, O, OH) and the sensitivity of the dominant reactions contributing to NO formation in the counter-flow diffusion flames of CH4\/ N2 /O2 and CH4 / N2 / O2 / CO2 were obtained. The results indicated that the flame temperature and the amount of NO were reduced while the sensitivity of reactions to the prompt NO formation was gradually increased with the increasing strain rate. Furthermore, it is shown that with the increasing CO2 concentration in oxidizer, CO2 was directly involved in the reaction of NO consumption. The flame temperature and NO production were decreased dramatically and the mechanism of NO production was transformed from the thermal to prompt route.

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