Non-Premixed CH4 Combustion in a Porous Medium

Volume 3: Combustion Science and Engineering ◽

10.1115/imece2009-12945 ◽

2009 ◽

Author(s):

A. Tarokh ◽

A. A. Mohamad ◽

L. Jiang

Keyword(s):

Porous Medium ◽

Porous Media ◽

Combustion Zone ◽

Combustion Process ◽

Fiber Material ◽

Combustion Efficiency ◽

Premixed Combustion ◽

Maximum Temperature ◽

Wall Functions ◽

Ch4 Combustion

Combustion process is the major contributor to the air pollution, such as CO, unburned hydrocarbon, soot and NOx, etc. Porous media can be a good candidate for improving the combustion efficiency and reducing pollution formation. Premixed combustion has been extensively investigated in the literature, experimentally and computationally. However, investigation of non-premixed combustion in porous media is limited in the open literature, which is the topic of this paper. The present work deals with the numerical modeling of methane/air non-premixed combustion in porous media. Physical problem that is considered here is fuel jet which is injected to the air in free flame case and injected into a porous medium, in the porous medium combustion case. The flow is assumed turbulent and standard k-ε model with standard wall functions is used in the simulation. The solid porous structure is assumed to be composed of alumina fiber material with temperature dependent heat conductivity. Discrete Ordinate method is used to solve radiative transport equations. The governing equations are solved using finite volume method. The results show that the combustion in porous media has superior combustion efficiency and significantly lower NOx and CO emissions compare to the free flame. This is due to the lower maximum temperature in porous media combustion. In comparison with the free flame case where the combustion zone is narrow and long, the results shows the combustion zone in porous media is shorter in axial and wider in radial direction.

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Computational Analysis of Non-Premixed Combustion in a Scramjet Combustor With a Wedge Shaped Strut Injector

10.1115/fedsm2021-65951 ◽

2021 ◽

Author(s):

Sajal Katare ◽

Nagendra P. Yadav

Keyword(s):

Computational Analysis ◽

Static Pressure ◽

Computational Study ◽

Combustion Process ◽

Combustion Efficiency ◽

Reaction Model ◽

Premixed Combustion ◽

Cold Flow ◽

Flame Holder ◽

Scramjet Combustor

Abstract This paper focuses the computational study of non-premixed combustion in a scramjet combustor. The wedge shaped strut injector was used in the combustion process. In order to investigate the flame holding mechanism of the wedge shaped strut in supersonic flow, the two-dimensional coupled implicit RANS equations, the standard k-ε turbulence model and the finite-rate/eddy-dissipation reaction model are introduced to simulate the flow field of the hydrogen fueled scramjet combustor with a strut flame holder under different conditions. The static pressure of the case under the engine ignition condition is much higher than that of the case under the cold flow condition. The reflection of shock waves improves the mixing of hydrogen with the stream of inlet air and thus increases combustion efficiency. The mass flow rate of air is optimized for the best performance of engine.

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Effects of CO2 Dilution on the Premixed Combustion of CH4 in Microcombustor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.388.251 ◽

2013 ◽

Vol 388 ◽

pp. 251-256 ◽

Cited By ~ 2

Author(s):

Ghobad Bagheri ◽

Ehsan Hamidi ◽

Mazlan A. Wahid ◽

Aminuddin Saat ◽

Mohsin M. Sies

Keyword(s):

Dilution Rate ◽

Numerical Study ◽

Flame Temperature ◽

Combustion Process ◽

Premixed Combustion ◽

Maximum Temperature ◽

Inlet Velocity ◽

Suitable Material ◽

Micro Combustor ◽

Velocity Decrease

A numerical study on premixed combustion of CH4+ CO2+ Air in two dimensional is done. Parameters of inlet velocity and temperature of fuel and combustor geometry and size are considers the same but the CO2dilution rate changes. Results of this simulation shows that while the CO2dilution rate increases, flame temperature and velocity decrease. There is a limitation for increasing of CO2in the mixture. If amount of CO2in the mixture goes beyond the 47.7%, the fuel will lose its ability to be ignited and thus there will be no flame in the combustor. In addition, knowing the maximum temperature of flame may help to analyze the combustion process and choose suitable material in manufacturing the micro combustor.

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Computer Simulation of Combustion Process in a Piston Engine With a Porous Medium Regenerator

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4023973 ◽

2013 ◽

Vol 5 (4) ◽

Cited By ~ 2

Author(s):

Lei Zhou ◽

Maozhao Xie ◽

Ming Jia ◽

Junrui Shi

Keyword(s):

Porous Medium ◽

Combustion Process ◽

Kinetic Mechanism ◽

Combustion Efficiency ◽

Pollutant Emissions ◽

Mixture Formation ◽

Computational Fluid Dynamics Cfd ◽

Reduce Emissions ◽

Detailed Kinetic Mechanism ◽

Reciprocating Movement

In the regenerative engine, effective heat exchange and recurrence between gas and solid can be achieved by the reciprocating movement of a porous medium regenerator in the cylinder, which considerably promotes the fuel-air mixture formation and a homogeneous and stable combustion. A two-dimensional numerical model for the regenerative engine is presented in this study based on a modified version of the engine computational fluid dynamics (CFD) software KIVA-3V. The engine was fueled with methane and a detailed kinetic mechanism was used to describe its oxidation process. The characteristics of combustion and emission of the engine were computed and analyzed under different equivalence ratios and porosities of the regenerator. Comparisons with the prototype engine without the regenerator were conducted. Results show that the regenerative engine has advantages in both combustion efficiency and pollutant emissions over the prototype engine and that using lower equivalence ratios can reduce emissions significantly, while the effect of the porosity is dependent on the equivalence ratio used.

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Experimental Research on Premixed Porous Media Combustion in Multiple Ejection/Tangential Burner

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.709.83 ◽

2014 ◽

Vol 709 ◽

pp. 83-86

Author(s):

Jiang Rong Xu ◽

Xiang Xiang Chen ◽

Guan Qing Wang

Keyword(s):

Porous Medium ◽

Porous Media ◽

Temperature Distribution ◽

Experimental Research ◽

Premixed Combustion ◽

Experimental Results ◽

Ignition Characteristic ◽

Porous Media Combustion

In this paper, the experimental research of porous media combustion was carried on premixed combustion of multiple ejection/tangential burner, the ignition characteristic, the resistance characteristics and the temperature distribution in the burner were obtained, and the experimental results were analyzed in detailed, which can provide references for the improvements of novel porous medium burner.

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Conservative solute transport with periodic velocity and sinusoidal source concentration in semi-infinite porous media: An analytical solution

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v6i1.1818 ◽

2014 ◽

Vol 6 (1) ◽

pp. 1024-1031

Author(s):

R R Yadav ◽

Gulrana Gulrana ◽

Dilip Kumar Jaiswal

Keyword(s):

Porous Medium ◽

Porous Media ◽

Laplace Transformation ◽

Seepage Velocity ◽

Transformation Technique ◽

Numerical Examples ◽

One Dimensional ◽

Porous Domain ◽

Conservative Solute Transport ◽

Source Concentration

The present paper has been focused mainly towards understanding of the various parameters affecting the transport of conservative solutes in horizontally semi-infinite porous media. A model is presented for simulating one-dimensional transport of solute considering the porous medium to be homogeneous, isotropic and adsorbing nature under the influence of periodic seepage velocity. Initially the porous domain is not solute free. The solute is initially introduced from a sinusoidal point source. The transport equation is solved analytically by using Laplace Transformation Technique. Alternate as an illustration; solutions for the present problem are illustrated by numerical examples and graphs.

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Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

Current Alternative Energy ◽

10.2174/2405463104666200120113721 ◽

2020 ◽

Vol 04 ◽

Author(s):

Guohai Jia ◽

Lijun Li ◽

Li Dai ◽

Zicheng Gao ◽

Jiping Li

Keyword(s):

Combustion Chamber ◽

Combustion Temperature ◽

Combustion Efficiency ◽

Middle Part ◽

Combustion Characteristics ◽

Maximum Temperature ◽

Excess Air ◽

Element Simulation ◽

Excess Air Coefficient ◽

Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

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Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽

10.3390/en12061036 ◽

2019 ◽

Vol 12 (6) ◽

pp. 1036 ◽

Cited By ~ 4

Author(s):

Xinying Xu ◽

Qi Chen ◽

Mifeng Ren ◽

Lan Cheng ◽

Jun Xie

Keyword(s):

Power Plant ◽

Combustion Process ◽

Optimization Method ◽

Combustion Efficiency ◽

Pollutant Emissions ◽

Combustion Model ◽

Nox Emissions ◽

Coupling Characteristics ◽

Learning Machine ◽

Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

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Capillary Imbibition Dynamics in Porous Media

ASME 2014 12th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2014-21120 ◽

2014 ◽

Author(s):

Swayamdipta Bhaduri ◽

Pankaj Sahu ◽

Siddhartha Das ◽

Aloke Kumar ◽

Sushanta K. Mitra

Keyword(s):

Porous Medium ◽

Porous Media ◽

Paper Strip ◽

Capillary Imbibition ◽

Flow Physics ◽

Fundamental Understanding ◽

Paper Based Microfluidics ◽

To Come

The phenomenon of capillary imbibition through porous media is important both due to its applications in several disciplines as well as the involved fundamental flow physics in micro-nanoscales. In the present study, where a simple paper strip plays the role of a porous medium, we observe an extremely interesting and non-intuitive wicking or imbibition dynamics, through which we can separate water and dye particles by allowing the paper strip to come in contact with a dye solution. This result is extremely significant in the context of understanding paper-based microfluidics, and the manner in which the fundamental understanding of the capillary imbibition phenomenon in a porous medium can be used to devise a paper-based microfluidic separator.

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Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

Energies ◽

10.3390/en14092729 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2729

Author(s):

Ireneusz Pielecha ◽

Sławomir Wierzbicki ◽

Maciej Sidorowicz ◽

Dariusz Pietras

Keyword(s):

Heat Release ◽

Combustion Chamber ◽

Internal Combustion Engines ◽

Direct Injection ◽

Combustion Process ◽

Combustion Efficiency ◽

Injection System ◽

Rapid Compression Machine ◽

Process Indicators ◽

Rapid Compression

The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

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