Analysis of Premixed Laminar Combustion of Methane With Noble Gases as a Working Fluid

2021 ◽  
Author(s):  
Mammadbaghir Baghirzade ◽  
Md Nayer Nasim ◽  
Behlol Nawaz ◽  
Jonathan Aguilar ◽  
Martia Shahsavan ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Noble Gases ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Diagnostic Technique ◽  
Methane Combustion ◽  
Working Fluid ◽  
Driving Mechanism ◽  
Hydrodynamic Instabilities ◽  
Premixed Laminar

Abstract Hydrodynamic and diffusional-thermal instabilities affect the flame dynamics, which result in non-planar flame fronts with self-accelerating cellularities and wrinkles. In premixed flames, the driving mechanism for perturbations is hydrodynamic instabilities, which are associated with thermal expansion. Under high-pressure conditions, such as in spark-ignition engines, the flame curvature and morphology might be influenced by the hydrodynamic instabilities. This study focuses on the replacement of nitrogen with a noble gas (argon and krypton) as the working fluid in the premixed combustion of methane to investigate its effect on flame stability and dynamics. The utilization of noble gases can also enhance the ideal thermal efficiency of internal combustion engines due to the higher specific heat ratio they possess and may also reduce the NOx emissions markedly because of the lack of nitrogen in the working fluid. The experiments are conducted for various equivalence ratios (φ = 0.8, 1.0, 1.2) in a constant volume combustion chamber (CVCC) at atmospheric and elevated initial pressures and atmospheric temperature. As an outcome of this study, to understand the influence of krypton on methane combustion, spherically propagating flames are analyzed in terms of the laminar flame burning velocity, cellular instability, unburned gas Markstein length, and flame morphology utilizing a Z-type Schlieren optical diagnostic technique and fractal analysis, which is a promising approach to analyze flame surfaces. The fractal dimension of the flame fronts is calculated by a box-counting algorithm. The results are compared against the previously examined case studies in which argon was used as the primary working fluid.

An Investigation of Laminar Flame Speed of CH4-O2-CO2 Mixtures

2019 ◽  
Author(s):  
Mattias A. Turner ◽  
Tyler Paschal ◽  
Waruna D. Kulatilaka ◽  
Eric L. Petersen
Keyword(s):  
Supercritical Co2 ◽  
Carbon Capture ◽  
High Speed ◽  
Laminar Flame ◽  
Full Range ◽  
Methane Combustion ◽  
Fuel Combustion ◽  
Flame Speed ◽  
Working Fluid ◽  
Laminar Flame Speed

Abstract The push for lower carbon emissions in power generation has driven interest in methods of carbon capture and sequestration. One such promising method involves the supercritical CO2 (sCO2) power cycle, a system which is powered by oxy-fuel combustion where supercritical carbon dioxide is used as the working fluid. The high CO2 concentration in the combustion products allows for relatively simple extraction of CO2 from the system. Although this is an active field of research, the design of such a combustor requires continued study of oxy-fuel combustion in high levels of CO2 diluent. With that objective in mind, laminar flame experiments were conducted for CH4-O2-CO2 mixtures at one atmosphere and room temperature, where the relative concentrations of O2 and CO2 in the oxidizer mixture were 34.0% and 66.0% by mole, respectively. These concentrations were chosen to ensure the flame would propagate quickly enough to overcome the effects of buoyancy, which were observed to become significant below laminar flame speeds of roughly 15 cm/s. A high-speed chemiluminescence imaging diagnostic was employed in place of the traditional schlieren technique. Laminar flame speed was measured from OH* emission at 306 nm for a full range of equivalence ratios, varying from 15.2 cm/s at 0.7 to 24.8 cm/s at stoichiometric. Additionally, images of OH* chemiluminescence of turbulent CH4-O2-CO2 flames and of quiescent, 5-atm CH4-O2-CO2 flames at stoichiometric concentration are also presented. These experiments provide useful data for validation of chemical kinetics models for oxy-methane combustion in a CO2 diluent, which can be applied to the modeling of oxy-methane combustion for supercritical CO2 power cycles.

Influence of Radiation Reabsorption on Laminar Burning Velocity of Methane Premixed Flame Composed With Steam and Carbon Dioxide

2005 ◽  
Author(s):  
Takumi Ebara ◽  
Norihiko Iki ◽  
Sanyo Takahashi ◽  
Won-Hee Park
Keyword(s):  
Carbon Dioxide ◽  
Gas Turbine ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Chemical Kinetic ◽  
Laminar Burning Velocity ◽  
Premixed Laminar ◽  
Kinetic Calculations ◽  
Reforming Gas ◽  
Radiation Reabsorption

Replacing the Nitrogen with another kind of inert gas such as steam and Carbon dioxide is effective for both reducing NOx and enhancing system efficiency in gas turbine combustor. But the flame properties of such radiative mixture are complicated because of the third body effect and radiation reabsorption. So, we made detailed chemical kinetic calculations including the effect of radiation reabsorption to clarify the premixed laminar flame speed of such mixture as one of the most important properties for controlling the combustion. The concentrations of mixture are varied, and addition of other species such as Carbon monoxide and Hydrogen are also calculated to simulate the utilization of reforming gas and partially oxidized gas. And the pressure was varied up to 5.0 MPa to simulate the 1700 °C class combined gas turbine system. The results show remarkable incensement of laminar burning velocity by considering the radiation reabsorption. Laminar burning velocities were accelerated up to 150% in cases of Methane–Oxygen and steam or Carbon dioxide mixture. It was found that preheating of upstream-unburned mixture caused this acceleration. And the influence of radiation reabsorption was much larger in case of lower pressure.

scholarly journals The Effect of Working Fluids on Premixed Hydrogen Combustion in a Constant Volume Combustion Chamber

2019 ◽  
Author(s):  
Mohammadrasool Morovatiyan ◽  
Martia Shahsavan ◽  
Jonathan Aguilar ◽  
John Hunter Mack
Keyword(s):  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Burning Velocity ◽  
Constant Volume ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Working Fluid ◽  
Laminar Burning Velocity ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber

Premixed combustion of hydrogen was investigated with the purpose of examining the effect of the full or partial substitution of argon for nitrogen in air on laminar burning velocity. Theoretically, this partial replacement decreases the NOx emissions and increases the thermal efficiency of internal combustion engines due to the high specific heat ratio of noble gases. An optically-accessible constant volume combustion chamber (CVCC) with central ignition was used to study flame propagation, flame morphological structure, and instability. The spherical flame development was studied using a high-speed Z-type Schlieren visualization system. Moreover, a numerical model was developed to convert the pressure rise data to laminar burning velocity. Coupling the model to a chemical equilibrium code aids in determining the burned gas properties. The experimental and numerical investigations indicate that increasing the concentration of argon as the working fluid in the mixture can increase the laminar burning velocity and extend the lean flammability limit.

scholarly journals Laminar Flame Characteristics of Premixed Methanol–Water–Air Mixture

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6504
Author(s):  
Zhennan Zhu ◽  
Kun Liang ◽  
Xinwen Chen ◽  
Zhongwei Meng ◽  
Wenbin He ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Molar Fraction ◽  
Stoichiometric Ratio ◽  
Gaseous State ◽  
Promising Alternative ◽  
Water Fraction ◽  
Flame Instability ◽  
Preferential Diffusion

Methanol is hygroscopic in a gaseous state and is a promising alternative fuel for internal combustion engines. It is understood that adding water can improve the antiknock performance for spark ignition engines, but this will also affect the flame speed and stability. In this work, laminar flame characteristics of methanol/water/air mixtures were experimentally investigated at a temperature range of 380–450 K, a pressure range of 1–4 bar, and water fractions (vaporous water molar fraction in the water–methanol fuel gas) of 0–40%. The results show that laminar burning velocity increases with temperature but decreases with pressure. The burning velocity decreases linearly with water fraction at a stoichiometric ratio. For rich mixtures and high pressures, the laminar flames tend to be more sensitive to stretch and, thus, more prone to being unstable. Increasing the water fraction can slightly increase the Markstein length. Increasing the initial pressure enhances the general flame instability, while increasing the initial temperature suppresses the general flame instability. Increasing the water fraction can lead to a decreasing thermal expansion ratio and an elevated flame thickness, both of which can lead to a suppression of hydrodynamic instability. An increase in the water fraction decreases the Lewis number, resulting in preferential diffusion instability. There is no direct relationship between the onset of cellularity and general flame instability.

Prediction of Premixed Laminar Flame Structure and Burning Velocity of Aviation Fuel-Air Mixtures

2001 ◽  
Author(s):  
A. G. Kyne ◽  
P. M. Patterson ◽  
M. Pourkashanian ◽  
C. W. Wilson ◽  
A. Williams
Keyword(s):  
Reaction Mechanism ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Flame Structure ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Aviation Fuel ◽  
Measured Temperature ◽  
Premixed Laminar ◽  
Increasing Temperature

The structure of a rich burner stabilised kerosene/O2/N2 flame is predicted using a detailed chemical kinetic mechanism where the kerosene is represented by a mixture of n-decane and toluene. The chemical reaction mechanism, consisting of 440 reactions between 84 species, is capable of predicting the experimentally determined flame structure of Douté et al. (1995) with good success using the measured temperature profile as input. Sensitivity and reaction rate analyses are carried out to identify the most significant reactions and based on this the reaction mechanism was reduced to one with only 165 reactions without any loss of accuracy. Burning velocities of kerosene-air mixtures were also determined over an extensive range of equivalence ratios at atmospheric pressure. The initial temperature of the mixture was also varied and burning velocities were found to increase with increasing temperature. Burning velocities calculated using both the detailed and reduced mechanisms were essentially identical.

Experimental and Numerical Study on Diluted Premixed Laminar Dimethyl Ether-Air Flames

2013 ◽  
Vol 732-733 ◽  
pp. 18-22
Author(s):  
Zhao Yang Chen ◽  
Chong Long Tang
Keyword(s):  
Carbon Dioxide ◽  
Dimethyl Ether ◽  
Laminar Flame ◽  
Numerical Study ◽  
Burning Velocity ◽  
Direct Reaction ◽  
Laminar Burning Velocity ◽  
Suppression Effect ◽  
Premixed Laminar ◽  
Good Agreement

Effects of diluents on premixed laminar dimethyl ether (DME)/air flames were studied experimentally and numerically. The results show that measurements and predictions in laminar burning velocities are in reasonably good agreement. Laminar flame speeds of DME mixtures decrease with the increase of dilution ratio. For a specific diluent ratio, suppression effect of diluent decreases in the order of carbon dioxide, nitrogen and argon. Influences of argon and nitrogen are mainly due to the increase of specific heat of the non-fuel gases in the mixture, and that of carbon dioxide is resulted from the combination effect of dilution and direct reaction. CO2 participating reaction, CO+OHCO2+H, competes for H radical in the chain branching reaction H+O2 O+OH. This competition decreases concentration of the radicals like H, O and OH, leading to a significant reduction in laminar burning velocity.

scholarly journals Laminar Burning Velocity of Biogas-Containing Mixtures. A Literature Review

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 996
Author(s):  
Venera Giurcan ◽  
Codina Movileanu ◽  
Adina Magdalena Musuc ◽  
Maria Mitu
Keyword(s):  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Combustion Engine ◽  
Burning Velocity ◽  
Internal Combustion ◽  
Electricity Production ◽  
Engine Fuel ◽  
Laminar Burning Velocity ◽  
Waste Products

Currently, the use of fossil fuels is very high and existing nature reserves are rapidly depleted. Therefore, researchers are turning their attention to find renewable fuels that have a low impact on the environment, to replace these fossil fuels. Biogas is a low-cost alternative, sustainable, renewable fuel existing worldwide. It can be produced by decomposition of vegetation or waste products of human and animal biological activity. This process is performed by microorganisms (such as methanogens and sulfate-reducing bacteria) by anaerobic digestion. Biogas can serve as a basis for heat and electricity production used for domestic heating and cooking. It can be also used to feed internal combustion engines, gas turbines, fuel cells, or cogeneration systems. In this paper, a comprehensive literature study regarding the laminar burning velocity of biogas-containing mixtures is presented. This study aims to characterize the use of biogas as IC (internal combustion) engine fuel, and to develop efficient safety recommendations and to predict and reduce the risk of fires and accidental explosions caused by biogas.

scholarly journals The Security of Energy Supply from Internal Combustion Engines Using Coal Mine Methane—Forecasting of the Electrical Energy Generation

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3049
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Klaudia Zwolińska ◽  
Rafał Łuczak ◽  
Zbigniew Kuczera
Keyword(s):  
Coal Mine ◽  
Predictive Models ◽  
Coalbed Methane ◽  
Internal Combustion Engines ◽  
Drainage System ◽  
Production Capacity ◽  
Methane Combustion ◽  
Economic Benefits ◽  
Electricity Production ◽  
Coal Mine Methane

Increasing emissions from mining areas and a high global warming potential of methane have caused gas management to become a vital challenge. At the same time, it provides the opportunity to obtain economic benefits. In addition, the use of combined heat and power (CHP) in the case of coalbed methane combustion enables much more efficient use of this fuel. The article analyses the possibility of electricity production using gas engines fueled with methane captured from the Budryk coal mine in Poland. The basic issue concerning the energy production from coalbed methane is the continuity of supply, which is to ensure the required amount and concentration of the gas mixture for combustion. Hence, the reliability of supply for electricity production is of key importance. The analysis included the basic characterization of both the daily and annual methane capture by the mine’s methane drainage system, as well as the development of predictive models to determine electricity production based on hourly capture and time parameters. To forecast electricity production, predictive models that are based on five parameters have been adopted. Models were prepared based on three time variables, i.e., month, day, hour, and two values from the gas drainage system-capture and concentration of the methane. For this purpose, artificial neural networks with different properties were tested. The developed models have a high value of correlation coefficient. but showed deviations concerning the very low values persisting for a short time. The study shows that electricity production forecasting is possible, but it requires data on many variables that directly affect the production capacity of the system.

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