Studies of the Combustion Process with Simultaneous Formaldehyde and OH PLIF in a Direct-Injected HCCI Engine(HCCI, Combustion Processes II)

A numerical study was carried out to evaluate the influence of engine combustion chamber geometry and operating conditions on the performance and emissions of a homogeneous charge compression ignition (HCCI) engine. Combustion in an HCCI engine is a very complex phenomenon that is influenced by several factors that need to be controlled, such as gas temperature, heat transfer, turbulence and auto-ignition of the gas mixture. An eddy dissipation concept (EDC) combustion model was used to take into account the interaction between turbulence and chemistry. The model assumed that reactions occur in small turbulent structures called fine-scales, whose characteristic lengths and times depend mainly on the turbulence level. The model parameters were slightly modified with respect to the standard model proposed by Magnussen, to correctly simulate the characteristics of the HCCI combustion process. A reduced iso-octane chemical mechanism with 186 species and 914 chemical reactions was employed together with a sub-mechanism for NOx. The model was validated by comparing the results with available experimental data in terms of pressure and instantaneous heat release rate. Two engine chamber geometries with and without a cavity in the piston were considered, respectively. The two engines provided significant differences in terms of fluid-dynamic patterns and turbulence intensity levels in the combustion chamber. The results show that combustion started earlier and proceeded faster for the flat piston, leading to an increase in both the peak pressure and gross indicated mean effective pressure, as well as a reduction of CO and UHC emissions. An additional analysis was performed by considering a case without swirl for the flat-piston case. Such an analysis shows that the swirl motion reduces the time duration of combustion and slightly increases the gross indicated work per cycle.

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Effects of Catalysts on Emissions of Pollutants from Combustion Processes of Liquid Fuels

Civil and Environmental Engineering Reports ◽

10.2478/ceer-2014-0011 ◽

2014 ◽

Vol 13 (2) ◽

pp. 5-17

Author(s):

Agnieszka Bok ◽

Joanna Guziałowska-Tic ◽

Wilhelm Jan Tic

Keyword(s):

Combustion Process ◽

Combustion Products ◽

Organometallic Complexes ◽

Liquid Fuels ◽

Motor Fuels ◽

Harmful Emissions ◽

Fuel Oils ◽

Sulphur Oxides ◽

Dynamic Growth ◽

Combustion Processes

Abstract The dynamic growth of the use of non-renewable fuels for energy purposes results in demand for catalysts to improve their combustion process. The paper describes catalysts used mainly in the processes of combustion of motor fuels and fuel oils. These catalysts make it possible to raise the efficiency of oxidation processes simultanously reducing the emission of pollutants. The key to success is the selection of catalyst compounds that will reduce harmful emissions of combustion products into the atmosphere. Catalysts are introduced into the combustion zone in form of solutions miscible with fuel or with air supplied to the combustion process. The following compounds soluble in fuel are inclused in the composition of the described catalysts: organometallic complexes, manganese compounds, salts originated from organic acids, ferrocen and its derivatives and sodium chloride and magnesium chloride responsible for burning the soot (chlorides). The priority is to minimize emissions of volatile organic compounds, nitrogen oxides, sulphur oxides, and carbon monoxide, as well as particulate matter.

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Mechanisms and kinetics of initial pyrolysis and combustion reactions of 1,1-diamino-2,2-dinitroethylene from density functional tight-binding molecular dynamics simulations

Canadian Journal of Chemistry ◽

10.1139/cjc-2019-0141 ◽

2019 ◽

Vol 97 (11) ◽

pp. 795-804 ◽

Cited By ~ 1

Author(s):

Dong Xiang ◽

Weihua Zhu

Keyword(s):

Activation Energy ◽

Molecular Dynamics ◽

Density Functional ◽

Tight Binding ◽

Combustion Process ◽

Exponential Factor ◽

Three Stages ◽

Dynamics Simulations ◽

Combustion Processes ◽

Kinetics Of

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.

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Improvement of CFD models of tunnel fire development based on experimental data

Thermal Science ◽

10.2298/tsci160201192v ◽

2017 ◽

Vol 21 (suppl. 3) ◽

pp. 705-716 ◽

Cited By ~ 1

Author(s):

Barbara Vidakovic ◽

Milos Banjac

Keyword(s):

Experimental Data ◽

Combustion Process ◽

Burning Surface ◽

Physical Structure ◽

Cfd Model ◽

Change Rate ◽

Flamelet Model ◽

Tunnel Fire ◽

Cfd Models ◽

Combustion Processes

This paper, dealing with the problems of mathematical description of the tunnel fire development process with the use of experimental data, outlines the procedure of correction of the existing and obtaining of an improved CFD model package. The improved CFD model was developed on the basis of detailed analysis and comparison of experimental and numerical results, through consideration of the physical structure of all processes affecting combustion. During the analysis it was noticed that the existing CFD model in the part covering combustion based on the so-called steady laminar flamelet model, treats the combustion process almost as a direct correlation between the processes of mixing gasses and heat release rate. This potential deficiency has been overcome by correction of the model in the section defining boundary condition for the burning surface and by establishing a direct correlation between the measured value of the fuel mass change rate and the amount of heat released from burning surface. In this way a modification of complex stoichiometric combustion processes was avoided, while providing the model that better describes and predicts the course of events in this type of complex, anisotropic and turbulent flow of gases in the tunnel.

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Reduction of Major Pollutants via Air-staged Commbustion on Burner System

Jurnal Teknologi ◽

10.11113/jt.v64.1664 ◽

2013 ◽

Vol 64 (1) ◽

Author(s):

Mohammad Nazri Mohd. Jaafar ◽

Mohd Nur Hanafi Zaini

Keyword(s):

Combustion Process ◽

Primary Concern ◽

Nox Emissions ◽

Percent Reduction ◽

Secondary Air ◽

Secondary Zone ◽

Combustion Processes ◽

Different Gases ◽

Air Staging ◽

Co Emission

Emission from the combustion processes can cause adverse effect to the environment. The formation of pollutants such as NOx, CO, CO2 and SOx are hazardous and harmful to the ecosystem. The awareness about the pollution due to the combustion activities, particularly in industrial field has set off an effort to find more comprehensive and enhanced technologies to reduce these pollutants. There are several methods that can be used to reduce the emissions of these pollutants either by combustion modifications or post combustion treatment. In this research, the method used is the post combustion treatment, i.e. the air staging method. By air staging techniques, some of the combustion air will be directed into the primary combustion zone, while the remaining air is directed into the secondary zone. The function of the secondary air is to reduce the peak flame temperatures, which theoretically reduce the emissions of NOx emissions. The primary concern for this research is to study the effectiveness of the air staging in reducing NOx, CO, SO2, and UHC emissions from the combustion process. The results obtained showed significant reduction in all major pollutants, i.e., a 31.8 percent reduction for CO emission, 16.8 percent for NOx, 12.7 percent for SO2 and 10.3 percent for UHC. These reductions were obtained at different equivalence ratios for different gases.

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LASER SYSTEM FOR STUDYING THE DYNAMICS OF HIGH TEMPERATURE COMBUSTION

Interexpo GEO-Siberia ◽

10.33764/2618-981x-2019-4-2-154-162 ◽

2019 ◽

Vol 4 (2) ◽

pp. 154-162

Author(s):

Lin Li ◽

Fedor Gubarev ◽

Andrei Mostovshchikov ◽

Alexander Ilyin

Keyword(s):

High Temperature ◽

Narrow Band ◽

Laser System ◽

Combustion Process ◽

Visual Observation ◽

Copper Bromide ◽

Temperature Combustion ◽

Temporal And Spatial ◽

Combustion Processes ◽

High Temperature Combustion

The paper is devoted to development of methods for studying the dynamics of high-temperature combustion of aluminum nanopowder.The difficulty in studying the combustion of nanopowders is the high temperature and intensity of light emissionduring the combustion process, which makes the visual observation virtually impossible.The paper discusses various schemes using laser radiation to study the combustion processes of metal nanopowders.Particular mentions the use of the laser monitor based on an active medium on copper bromide vapor to study the combustion process of various powders and mixtures.The laser monitor combines the functions of the narrow-band laser illuminator and the brightness amplifier, thereby achieving the visualization at a narrow gain wavelength. Therefore, the laser monitor can be used to observe the changes in the surface of a burning sample with high temporal and spatial resolution.

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Analysis of the possibilities to achieve adiabatization process of combustion surrounded by inactive gases in Rapid Compression Machine

Combustion Engines ◽

10.19206/ce-2017-104 ◽

2017 ◽

Vol 168 (1) ◽

pp. 27-31

Author(s):

Wojciech CIEŚLIK ◽

Ireneusz PIELECHA

Keyword(s):

Combustion Process ◽

Combustible Mixture ◽

Spark Ignition Engine ◽

Rapid Compression Machine ◽

Working Medium ◽

Main Injection ◽

Rapid Compression ◽

Combustible Gases ◽

Combustion Processes ◽

Combustible Mixtures

In this work non-combustible gases impact on combustion processes studies is performed. Research was performed in a optically accessible rapid compression machine (RCM) under spark ignition engine conditions. The distribution of the swirl charge in the relation to adopted for analysis sequence of gas delivery to the chamber was varied with regard to the main injection. Authors investigate the influence of these sequence on the combustion and the ignition delay of the main injection and the overall combustion characteristics. The aim of this work is the experimental recognition of possibilities of creating combustible mixtures of light hydrocarbon fuels surrounded by non-combustible gases affecting the function of the inhibitor. Specifying the ability of preparation and combustion of mixtures in such systems enables the scientific analysis of adiabatization of the combustion process of fuel-air mixtures in the operating chambers. Theoretical analysis of the issues indicates possibility of obtaining such a stratification of the charge, that the inactive exhaust gases creating the outer ring surround the combustible mixture inside in such a way as to reduce the amount of heat exchanged between the working medium and the walls of the cylinder.

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Analysis of thermodynamic parameters in spark ignition VCR engine

MATEC Web of Conferences ◽

10.1051/matecconf/201929405001 ◽

2019 ◽

Vol 294 ◽

pp. 05001

Author(s):

Patryk Urbański ◽

Maciej Bajerlein ◽

Jerzy Merkisz ◽

Andrzej Ziółkowski ◽

Dawid Gallas

Keyword(s):

Thermodynamic Parameters ◽

Motion Analysis ◽

Internal Combustion Engines ◽

Initial Conditions ◽

Combustion Process ◽

Internal Combustion ◽

3D Models ◽

Spark Ignition ◽

Combustion Engines ◽

Combustion Processes

3D models of Szymkowiak and conventional engines were created in the Solidworks program. During the motion analysis, the characteristics of the piston path were analyzed for the two considered engine units. The imported file with the generated piston routes was used in the AVL Fire program, which simulated combustion processes in the two engines with identical initial conditions. The configurations for two different compression ratios were taken into account. The basic thermodynamic parameters occurring during the combustion process in internal combustion engines were analyzed.

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