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

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.

2018 ◽  
Vol 17 (2) ◽  
pp. 03
Author(s):  
L. Pizzuti ◽  
C. A. Martins ◽  
L. R. Santos

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.


Author(s):  
Bidhan Dam ◽  
Vishwanath Ardha ◽  
Ahsan Choudhuri

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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