Characteristics of Ammonia-Nitric Oxide Combustion

2003 ◽  
Author(s):  
Rui Liu ◽  
David S.-K. Ting ◽  
M. David Checkel
Keyword(s):  
Nitric Oxide ◽  
Reaction Mechanisms ◽  
Equivalence Ratio ◽  
Burning Velocity ◽  
Flame Temperature ◽  
Laminar Burning Velocity ◽  
Flammability Limits ◽  
Constant Volume Combustion Chamber ◽  
Experimental Values ◽  
Peak Value

The combustion characteristics of premixed ammonia-nitric oxide mixtures at atmospheric and elevated conditions were numerically examined. The laminar burning velocity, flame temperature and flammability limits were determined using the GRI 3.0 and the Miller-Bowman 1989 reaction mechanisms in CHEMKIN. A freely propagating adiabatic flame was assumed to facilitate the investigation. The laminar burning velocities and the flammability limits predicted with the two mechanisms were compared with experimental values measured in a constant volume combustion chamber. The predicted flammability limits are at ammonia-nitric oxide equivalence ratios of 0.2 and 3.5. The predicted laminar burning velocity increases with the unburnt mixture temperature and decreases with the pressure with a peak value at ammonia-nitric oxide equivalence ratio of 0.9. The Miller-Bowman 1989 mechanism predicts results closer to the measured values than the GRI 3.0 mechanism when the laminar burning velocity is concerned. For the adiabatic flame temperature, the predictions from both mechanisms agree well with each other.

scholarly journals EXPERIMENTAL DETERMINATION OF LAMINAR BURNING VELOCITY OF BIOGAS AT PRESSURES UP TO 5 BAR

2018 ◽  
Vol 17 (2) ◽  
pp. 03
Author(s):  
L. Pizzuti ◽  
C. A. Martins ◽  
L. R. Santos
Keyword(s):  
Equivalence Ratio ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Experimental Setup ◽  
Laminar Burning Velocity ◽  
Gaseous Mixtures ◽  
Experimental Procedure ◽  
Constant Volume Combustion Chamber ◽  
Percentage Standard Deviation

This paper presents a very detailed description of a new cylindrical constant volume combustion chamber designed for laminar burning velocity determination of gaseous mixtures at ambient temperature and initial pressure up to 6 bar. The experimental setup, the experimental procedure and the determination of the range of flame radius for laminar burning determination are all described in details. The laminar burning velocity of twelve synthetic biogas mixtures has been studied. Initial pressure varying between 1 and 5 bar, equivalence ratios, f, between 0.7 and 1.1 and percentage dilution, with a mixture of CO2 and N2, between 35 and 55% have been considered. Five experiments were run for each mixture providing a maximum percentage standard deviation of 8.11%. However, for two third of the mixtures this value is lower than 3.55%. A comparison with simulation using PREMIX for both GRI-Mech 3.0 and San Diego mechanisms has provided closer agreement for mixtures with equivalence ratio closer to stoichiometry whereas for f = 0.7 the deviation is larger than 15% for all pressures. Mixtures with lower equivalence ratio, higher dilution percentage and higher initial pressure presents the lower values of laminar burning velocity.

Fundamental Combustion Characteristics of Lean and Stoichiometric Hydrogen Laminar Premixed Flames Diluted With Nitrogen or Carbon Dioxide

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Hong-Meng Li ◽  
Guo-Xiu Li ◽  
Zuo-Yu Sun ◽  
Zi-Hang Zhou ◽  
Yuan Li ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Equivalence Ratio ◽  
Burning Velocity ◽  
Flame Temperature ◽  
Premixed Flames ◽  
Combustion Characteristics ◽  
Inert Gas ◽  
Chemical Effect ◽  
Laminar Burning Velocity ◽  
Suppression Effect

In this work, the laminar combustion characteristics of H2/N2/air (H2/CO2/air) were systematically investigated under different hydrogen ratios (40–100%) and equivalence ratios (0.4–1.0) in a closed combustion vessel using the spherical expanding flame method associated with Schlieren technology. The unstretched laminar burning velocities were compared with data from previous study, and the result indicates that excellent agreements are obtained. Numerical simulations were also conducted using GRI3.0 and USC II mechanisms to compare with the present experimental results. The Markstein length for H2/inert gas can be decreased by decreasing the equivalence ratio and hydrogen ratio. The results indicate that the H2/inert gas premixed flames tend to be more unstable with the decrease of equivalence ratio and hydrogen ratio. For H2/N2 mixture, the suppression effect on laminar burning velocity is caused by modified specific heat of mixtures and decreased heat release, which result in a decreased flame temperature. For H2/CO2 mixture, the carbon dioxide has stronger dilution effect than nitrogen in reducing laminar burning velocity owing to both thermal effect and chemical effect.

Experimental and Computational Determination of LBV of Hydrogen Enriched Methane Mixtures

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Vinod Kumar Yadav ◽  
Ranjeet Singha ◽  
Abhishek Kumar Pandey ◽  
Saumya   ◽  
Ashish Kumar Singh ◽  
...  
Keyword(s):  
Coming Out ◽  
Burning Velocity ◽  
Laminar Burning Velocity ◽  
Flammability Limits ◽  
Ambient Temperatures ◽  
Gaseous Fuels ◽  
Wide Range ◽  
Hydrogen Enrichment ◽  
Institute Of Technology ◽  
Set Up

One of the major causes of environmental pollution and ozone layer depletion is the emissions coming out of the combustion devices including industrial burners, automobile vehicles and household appliances. Most of the conventional fuels used now days have high GWP and ODP. So the greatest challenges among the combustion researchers and scientists are to develop some sustainable and non conventional sources of energy that possesses capability to replace the conventional ones. One of the important gaseous fuels in non conventional category is hydrogen, which is a cleaner fuel and reduces pollution enormously. In the present work, experimental & computational analysis of laminar burning velocity (LBV) of premixed gaseous fuels (primary focus on Hydrogen enrichment) was carried out. For experimental investigation the experimental set up available in Fuel and pollution lab of Indian Institute of Technology Delhi is used. Experiments were carried out on mixtures of methane- Air and Methane-Hydrogen-Air for wide range of equivalence ratios and compared with the computational results of PREMIX with full GRI-Mech 3.0 mechanism. Most of the experiments available in literature were carried out at 298 K. In the present work it has been tried to relate the effect of low temperatures on laminar burning velocity of mixtures. The experiments have been conducted at 1 bar pressure and around 292 Kelvin with equivalence ratio ranging from 0.8 to 1.2. Methane gas is enriched with hydrogen in varying proportions and the effect of hydrogen enrichment on its laminar burning velocity studied. The objective of the addition of hydrogen to methane was to increase its laminar burning velocity as well as to extend its lean flammability limits at lower ambient temperatures.

Development of a Simulation Code for Hydrogen Fuelled SI Engines

2006 ◽  
Author(s):  
Sebastian Verhelst ◽  
Roger Sierens ◽  
Stefaan Verstraeten
Keyword(s):  
Alternative Energy ◽  
Equivalence Ratio ◽  
Internal Combustion Engines ◽  
Burning Velocity ◽  
Combustion Model ◽  
Laminar Burning Velocity ◽  
Velocity Correlation ◽  
Model Framework ◽  
Economic Point ◽  
Velocity Models

Hydrogen is an attractive alternative energy carrier, which could make harmful emissions, global warming and the insecurity concerning oil supply a thing of the past. Hydrogen internal combustion engines can be introduced relatively easily, from a technological as well as from an economic point of view. This paper discusses the development of a model for the combustion of hydrogen in spark ignition engines, which has lead to a simulation program that can assist the optimization of these engines. The importance of a laminar burning velocity correlation taking stretch and instability effects into account is shown. The effects are particularly strong for the highly diffusive hydrogen molecule. In this paper, a laminar burning velocity correlation published previously by two of the authors is combined with a number of turbulent burning velocity models in a quasi-dimensional two-zone combustion model framework. After calibration of the combustion model for a reference condition, simulation results are compared with experimental cylinder pressure data recorded on a single cylinder hydrogen engine. Correspondence between simulation and measurement is shown for varying equivalence ratio, ignition timing and compression ratio. All models performed well for varying ignition timings and compression ratios; the real test proved to be the ability of the models to predict the effects of a varying equivalence ratio, this lead to a clear distinction in the models.

FLAME PROPAGATION AND BURNING RATES OF METHANE-AIR MIXTURES USING SCHLIEREN PHOTOGRAPHY

2016 ◽  
Vol 78 (10-2) ◽  
Author(s):  
Mohd Suardi Suhaimi ◽  
Aminuddin Saat ◽  
Mazlan A. Wahid ◽  
Mohsin Mohd Sies
Keyword(s):  
Combustion Chamber ◽  
Burning Rate ◽  
Equivalence Ratio ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Markstein Length ◽  
Constant Volume Combustion Chamber ◽  
Burning Rates ◽  
Schlieren Photography

Different methodology have been shown to produce different results for Markstein length and laminar burning velocity of methane-air mixture.This study attempts to determine the aforesaid parameters using the newly developed closed vessel combustion chamber with Schlieren photography. Markstein length and burning rate of methane-air mixture was determined under the initial pressure of 1 atm, temperature range of 298-302K and equivalence ratio range of 0.7-1.3. Experiments were performed in a centrally ignited 29.16L cylindrical constant volume combustion chamber. Ignition energy was set at 25mJ for each experiment. The images of spherically expanding flame were recorded using Schlieren photography technique at a speed of 2000 frame per second. Analysis of the flame area yield flame radii from which the flame speed and stretch rate could be obtained. These parameters would allow the determination of Markstein length and burning rate of the flame. Results show that Markstein length magnitude increases proportionally with equivalence ratio with a magnitude ranging from 0.125cm to 0.245cm. Maximum burning rate occurs at equivalence ratio of 1.1 with a magnitude of 0.366 m/s. Flame of each equivalence ratio also exhibits fluctuation arising from acoustic disturbance. This disturbance becomes more apparent at higher equivalence ratio.

Experimental Study on Laminar Flame Speeds and Markstein Length of Methane-Air Mixtures at Atmospheric Conditions

2014 ◽  
Vol 699 ◽  
pp. 714-719
Author(s):  
Alaeldeen Altag Yousif ◽  
Shaharin Anwar Sulaiman
Keyword(s):  
High Speed ◽  
Equivalence Ratio ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Ambient Pressure ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Atmospheric Conditions ◽  
Laminar Burning Velocity ◽  
Markstein Length

Accurate value of laminar flame speed is an important parameter of combustible mixtures. In this respect, experimental data are very useful for modeling improvement and validating chemical kinetic mechanisms. To achieve this, an experimental characterization on spherically expanding flames propagation of methane-air mixtures were carried out. Tests were conducted in constant volume cylindrical combustion chamber to measure stretched, unstretched laminar flame speed, laminar burning velocity, and flame stretch effect as quantified by the associated Markstein lengths. The mixtures of methane-air were ignited at extensive ranges of lean-to-rich equivalence ratios, under ambient pressure and temperature. This is achieved by high speed schlieren cine-photography for flames observation in the vessel. The results showed that the unstretched laminar burning velocity increased and the peak value of the unstretched laminar burning velocity shifted to the richer mixture side with the increase of equivalence ratio. The flame propagation speed showed different trends at different equivalence ratio for tested mixtures. It was found that the Markstein length was increased with the increase of equivalence ratio.

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.

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