scholarly journals Determination of laminar burning velocity of methane/air flames in sub atmospheric environments

2021 ◽  
pp. 50-62
Author(s):  
Arley Cardona Vargas ◽  
Carlos E. Arrieta ◽  
Hernando Alexander Yepes Tumay ◽  
Camilo Echeverri-Uribe ◽  
Andrés Amell
Keyword(s):  
Energy Demand ◽  
Burning Velocity ◽  
Reynolds Numbers ◽  
Equivalence Relations ◽  
Laminar Burning Velocity ◽  
Oxidation Of Methane ◽  
Spontaneous Chemiluminescence ◽  
Polluting Emissions ◽  
The City

The global energy demand enhances the environmental and operational benefits of natural gas as an energy alternative, due to its composition, mainly methane (CH4), it has low polluting emissions and benefits in energy and combustion systems. In the present work, the laminar burning velocity of methane was determined numerically and experimentally at two pressure conditions, 0.85 atm and 0.98 atm, corresponding to the city of Medellín and Caucasia, respectively, located in Colombia. The environmental conditions were 0.85 atm, 0.98 atm, and 295±1 K. The simulations and experimental measurements were carried out for different equivalence relations. Experimental laminar burning velocities were determined using the burner method and spontaneous chemiluminescence technique, flames were generated using burners with contoured rectangular ports to maintain laminar Reynolds numbers for the equivalence ratios under study and to reduce the effects of stretch and curvature in the direction of the burner's axis. In general, the laminar burning velocity fits well with the numerical results. With the results obtained, a correlation is proposed that relates the laminar burning velocity with the effects of pressure, in the form SL=aPb, where a and b are model constants. Sensitivity analysis was performed using the GRI-Mech 3.0 mechanism which showed that the most sensitive reaction was H+O2=O+OH (R38). Additionally, it was found that the reactions H+CH3 (+M)=CH4 (+M) (R52), 2CH3 (+M)=C2H6 (+M) (R158), and O+CH3=H+CH2O (R10) dominate the consumption of CH3 which is an important radical in the oxidation of methane, this analysis is carried out for equivalence ratios of 0.8 and 1.0, and atmospheric pressures of 0.85 atm and 0.98 atm

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.

scholarly journals Laminar Burning Velocity of Lean Methane/Air Flames under Pulsed Microwave Irradiation

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2076
Author(s):  
Elna J. K. Nilsson ◽  
Tomas Hurtig ◽  
Andreas Ehn ◽  
Christer Fureby
Keyword(s):  
Microwave Irradiation ◽  
Pulse Sequence ◽  
Burning Velocity ◽  
Pulse Sequences ◽  
Average Power ◽  
Direct Determination ◽  
Microwave Cavity ◽  
Laminar Burning Velocity ◽  
Constant E

Laminar burning velocity of lean methane/air flames exposed to pulsed microwave irradiation is determined experimentally as part of an effort to accurately quantify the enhancement resulting from exposure of the flame to pulsed microwaves. The experimental setup consists of a heat flux burner mounted in a microwave cavity, where the microwave has an average power of up to 250 W at an E-field in the range of 350–380 kV/m. Laminar burning velocities for the investigated methane/air flames increase from 1.8 to 12.7% when exposed to microwaves. The magnitude of the enhancement is dependent on pulse sequence (duration and frequency) and the strength of the electric field. From the investigated pulse sequences, and at a constant E-field and average power, the largest effect on the flame is obtained for the longest pulse, namely 50 μs. The results presented in this work are, to the knowledge of the authors, the first direct determination of laminar burning velocity on a laminar stretch-free flame exposed to pulsed microwaves.

Laminar Flame Velocity of Syngas Fuels

2010 ◽  
Author(s):  
Bidhan Dam ◽  
Vishwanath Ardha ◽  
Ahsan Choudhuri
Keyword(s):  
Laminar Flame ◽  
Burning Velocity ◽  
Flame Velocity ◽  
Laminar Burning Velocity ◽  
Velocity Data ◽  
Flame Propagation Velocity ◽  
Exit Velocity ◽  
Flat Flame ◽  
Burner Exit

The paper presents the experimental measurements of the laminar burning velocity of H2-CO mixtures. Hydrogen (H2) and carbon monoxide (CO) are the two primary constituents of syngas fuels. Three burner systems (nozzle, tubular, and flat flame) are used to quantify the effects of burner exit velocity profiles on the determination of laminar flame propagation velocity. The effects to N2 and CO2 diluents have been investigated as well, and it is observed that the effects of N2 and CO2 on the mixture burning velocity are significantly different. Finally, the burning velocity data of various syngas compositions (brown, bituminous, lignite and coke) are presented.

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