Measurements and calculations of formaldehyde concentrations in a methane/N2/air, non-premixed flame: Implications for heat release rate

2009 ◽  
Vol 32 (1) ◽  
pp. 1311-1318 ◽  
Author(s):  
S.B. Dworkin ◽  
A.M. Schaffer ◽  
B.C. Connelly ◽  
M.B. Long ◽  
M.D. Smooke ◽  
...  
Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1405
Author(s):  
Kai Deng ◽  
Shenglang Zhao ◽  
Chenyang Xue ◽  
Jinlin Hu ◽  
Yi Zhong ◽  
...  

The effects of plasma on the combustion instability of a methane swirling premixed flame under acoustic excitation were investigated. The flame image of OH planar laser-induced fluorescence and the fluctuation of flame transfer function showed the mechanism of plasma in combustion instability. The results show that when the acoustic frequency is less than 100 Hz, the gain in flame transfer function gradually increases with the frequency; when the acoustic frequency is 100~220 Hz, the flame transfer function shows a trend of first decreasing and then increasing with acoustic frequency. When the acoustic frequency is greater than 220 Hz, the flame transfer function gradually decreases with acoustic frequency. When the voltage exceeds the critical discharge value of 5.3 kV, the premixed gas is ionized and the heat release rate increases significantly, thereby reducing the gain in flame transfer function and enhancing flame stability. Plasma causes changes in the internal recirculation zone, compression, and curling degree of the flame, and thereby accelerates the rate of chemical reaction and leads to an increase in flame heat release rate. Eventually, the concentration of OH radicals changes, and the heat release rate changes accordingly, which ultimately changes the combustion instability of the swirling flame.


2008 ◽  
Vol 18 (2) ◽  
pp. 111-124 ◽  
Author(s):  
C. Chen ◽  
L. Qu ◽  
Y. X. Yang ◽  
G. Q. Kang ◽  
W. K. Chow

2021 ◽  
Vol 11 (7) ◽  
pp. 3247
Author(s):  
Dong Hwan Kim ◽  
Chi Young Lee ◽  
Chang Bo Oh

In this study, the effects of discharge area and atomizing gas type in a twin-fluid atomizer on heptane pool fire-extinguishing performance were investigated under the heat release rate conditions of 1.17 and 5.23 kW in an enclosed chamber. Large and small full cone twin-fluid atomizers were prepared. Nitrogen and air were used as atomizing gases. With respect to the droplet size of water mist, as the water and air flow rates decreased and increased, respectively, the Sauter mean diameter (SMD) of the water mist decreased. The SMD of large and small atomizers were in the range of approximately 12–60 and 12–49 μm, respectively. With respect to the discharge area effect, the small atomizer exhibited a shorter extinguishing time, lower peak surface temperature, and higher minimum oxygen concentration than the large atomizer. Furthermore, it was observed that the effect of the discharge area on fire-extinguishing performance is dominant under certain flow rate conditions. With respect to the atomizing gas type effect, nitrogen and air appeared to exhibit nearly similar extinguishing times, peak surface temperatures, and minimum oxygen concentrations under most flow rate conditions. Based on the present and previous studies, it was revealed that the effect of atomizing gas type on fire-extinguishing performance is dependent on the relative positions of the discharged flow and fire source.


Fuel ◽  
2021 ◽  
Vol 288 ◽  
pp. 119656
Author(s):  
Robbert Willems ◽  
Frank Willems ◽  
Niels Deen ◽  
Bart Somers

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