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.

scholarly journals Effect of Hydrogen Content and Dilution on Laminar Burning Velocity and Stability Characteristics of Producer Gas-Air Mixtures

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
V. Ratna Kishore ◽  
M. R. Ravi ◽  
Anjan Ray
Keyword(s):  
Hydrogen Content ◽  
Alternative Fuels ◽  
Burning Velocity ◽  
Operating Conditions ◽  
Producer Gas ◽  
Laminar Burning Velocity ◽  
High Hydrogen ◽  
Promising Alternative ◽  
Preferential Diffusion ◽  
Wide Range

Producer gas is one of the promising alternative fuels with typical constituents of H2, CO, CH4, N2, and CO2. The laminar burning velocity of producer gas was computed for a wide range of operating conditions. Flame stability due to preferential diffusional effects was also investigated. Computations were carried out for spherical outwardly propagating flames and planar flames. Different reaction mechanisms were assessed for the prediction of laminar burning velocities of CH4, H2, H2-CO, and CO-CH4and results showed that the Warnatz reaction mechanism with C1 chemistry was the smallest among the tested mechanisms with reasonably accurate predictions for all fuels at 1 bar, 300 K. To study the effect of variation in the producer gas composition, each of the fuel constituents in ternary CH4-H2-CO mixtures was varied between 0 to 48%, while keeping diluents fixed at 10% CO2and 42% N2by volume. Peak burning velocity shifted fromϕ=1.6to 1.1 as the combined volumetric percentage of hydrogen and CO varied from 48% to 0%. Unstable flames due to preferential diffusion effects were observed for lean mixtures of fuel with high hydrogen content. The present results indicate that H2has a strong influence on the combustion of producer gas.

An Investigation of the Lean Operational Limits of Gas-Fueled Spark Ignition Engines

1996 ◽  
Vol 118 (2) ◽  
pp. 159-163 ◽  
Author(s):  
O. A. Badr ◽  
N. Elsayed ◽  
G. A. Karim
Keyword(s):  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Flammability Limit ◽  
Flammability Limits ◽  
Limit Values ◽  
Gaseous Fuels ◽  
Mean Temperature ◽  
Wide Range ◽  
The Mean ◽  
Temperature And Pressure

Examination is made of the operational limits in two variable compression-ratio single-cylinder engines when operating on the gaseous fuels methane, propane, LPG, and hydrogen under a wide range of conditions. Two definitions for the limits were employed. The first was associated with the first detectable misfire on leaning the mixture, while the second was the first detectable firing under motoring condition in the presence of a spark when the mixture was being enriched slowly. Attempts were also made to relate these limits to the corresponding values for quiescent conditions reckoned on the basis of the flammability limits evaluated at the mean temperature and pressure prevailing within the cylinder charge at the time of the spark. The measured limits in the engine were always higher than the corresponding flammability limit values for the three fuels. Both of these limits appear to correlate reasonably well with the calculated mean temperature of the mixture at the time of passing the spark.

A Thermodynamic Analysis of the Lean Flammability Limits of Fuel-Diluent Mixtures in Air

1994 ◽  
Vol 116 (3) ◽  
pp. 181-185 ◽  
Author(s):  
I. Wierzba ◽  
S. O. Bade Shrestha ◽  
G. A. Karim
Keyword(s):  
Thermodynamic Analysis ◽  
Initial Mixture ◽  
Flammability Limits ◽  
Temperature Range ◽  
Gaseous Fuels ◽  
Wide Range ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

A procedure is described for calculating the lean flammability limits of fuel-diluent mixtures in air over a wide range of fuel-diluent combinations and for different initial mixture temperatures. Good agreement is shown to exist between the predicted values of the limits with the corresponding experimental values for some common gaseous fuels that include CH4, C2H6, C2H4, C3H8, C4H10, H2, and CO and the diluents CO2, N2, He, and Ar over the temperature range of −60°C up to 400°C.

Laminar Burning Velocity of Methane–Air–Diluent Mixtures

2000 ◽  
Vol 123 (1) ◽  
pp. 190-196 ◽  
Author(s):  
M. Elia ◽  
M. Ulinski ◽  
M. Metghalchi
Keyword(s):  
Mass Fraction ◽  
Dynamic Pressure ◽  
Burning Velocity ◽  
Combustion Process ◽  
Numerical Differentiation ◽  
Constant Volume ◽  
Laminar Burning Velocity ◽  
Wide Range ◽  
Energy Equations ◽  
Gas Properties

An experimental facility for measuring burning velocity has been designed and built. It consists of a spherical constant volume vessel equipped with a dynamic pressure transducer, ionization probes, thermocouple, and data acquisition system. The constant volume combustion vessel allows for the determination of the burning velocity over a wide range of temperatures and pressures from a single run. A new model has been developed to calculate the laminar burning velocity using the pressure data of the combustion process. The model solves conservation of mass and energy equations to determine the mass fraction of the burned gas as the combustion process proceeds. This new method allows for temperature gradients in the burned gas and the effects of flame stretch on burning velocity. Exact calculations of the burned gas properties are determined by using a chemical equilibrium code with gas properties from the JANAF Tables. Numerical differentiation of the mass fraction burned determines the rate of the mass fraction burned, from which the laminar burning velocity is calculated. Using this method, the laminar burning velocities of methane–air–diluent mixtures have been measured. A correlation has been developed for the range of pressures from 0.75 to 70 atm, unburned gas temperatures from 298 to 550 K, fuel/air equivalence ratios from 0.8 to 1.2, and diluent addition from 0 to 15 percent by volume.

Further development of the three-region model of a premixed turbulent flame I. Turbulent diffusion dominated region 2

1979 ◽  
Vol 368 (1733) ◽  
pp. 267-282 ◽  
Keyword(s):  
Turbulence Intensity ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Turbulent Energy ◽  
Variable Density ◽  
Turbulent Flames ◽  
Laminar Burning Velocity ◽  
Advection Term ◽  
Set Up ◽  
Premixed Turbulent Flame

A study of the balance equation for turbulent kinetic energy of a premixed turbulent flame has been carried out. Various parameters constituting each term have either been measured or have been calculated from previously measured values. Propane and hydrogen were used as fuels, and the turbulence intensity of the approach flow was varied. Thus, an energy balance of turbulence in a flame has been set up. These results show that increase in both approach turbulence intensity and laminar burning velocity reduce the ratio of production/dissipation in a flame. Thus the stabilizing influence of laminar burning velocity is fully confirmed. The turbulent convection term is found to remain substantially unaltered. The advection term, on the other hand, changes from a loss to a gain in the turbulent energy of the flame. Finally, it is shown that significant differences exist between a flame and a non-reactive variable density axisymmetric jet. These conclusions make the study of turbulent flames unique in that theories that do not accommodate their special features should either be modified or abandoned.

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 Validation of Multi-Physics Integrated Procedure for the HCPB Breeding Blanket

2019 ◽  
Vol 17 (06) ◽  
pp. 1950009 ◽  
Author(s):  
R. Favetti ◽  
P. Chiovaro ◽  
P. A. Di Maio ◽  
G. A. Spagnuolo
Keyword(s):  
Nuclear Power ◽  
Analysis Tool ◽  
Analysis Software ◽  
Transport Code ◽  
Wide Range ◽  
Points Of View ◽  
Institute Of Technology ◽  
Set Up ◽  
Karlsruhe Institute

The wide range of requirements and constraints involved in the design of nuclear components for fusion reactors makes the development of multi-physics analysis procedures of utmost importance. In the framework of the European DEMO project, the Karlsruhe Institute of Technology (KIT) is dedicating several efforts to the development of a multi-physics analysis tool allowing the characterization of breeding blanket design points which are consistent from the neutronic, thermal-hydraulic and thermal-mechanical points of view. In particular, a procedure developed at KIT is characterized by the implementation of analysis software only. A preliminary step for the validation of such a procedure has been accomplished using a dedicated model of the DEMO Helium Cooled Pebble Bed Blanket 4th outboard module. A global model representative of nuclear irradiation in DEMO and two local models have been set up. Nuclear power deposition and the spatial distribution of its volumetric density have been calculated using Monte Carlo N-Particle transport code for the aforementioned models and compared in order to validate the procedure set up. The outcomes of this comparative study are herein presented and critically discussed.

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