Measurements of Laminar Flame Speeds of Alternative Gaseous Fuel Mixtures

Abstract

Global warming and the ever increasing emission levels o f combustion engines have forced the engine manufacturers to look fo r alternative fuels fo r high engine performance and low emissions. Gaseous fuel mixtures such as biogas, syngas, and liquefied petroleum gas (LPG) are new alternative fuels that have great potential to be used with combustion engines. In the present work, laminar flame speeds (S ,j o f alternative fuel mixtures, mainly LPG (60% butane, 20% isobutane, and 20% propane) and methane have been studies using the tube method at ambient conditions. In addition, the effect o f adding other fuels and gases such as hydrogen, oxygen, carbon dioxide, and nitrogen on SL has also been investigated. The results show that any change in the fuel mixture composition directly affects S,_. Measurements ofSL o f CHflLPG-air mixtures have found to be about 56cm/s at 0 = 1.1 with 60% LPG in the mixture, which is higher than SL o f both pure fuels at the same 0. Moreover, the addition ofH2 and 0 2 to the fuel mixtures increases SL notably, while the addition o f C 0 2IN2 mixture to the fuel mixture, to simulate the EGR effect, decreases SL o f CHflLPG-air mixtures.

Lean partially premixed turbulent flame equivalence ratio measurements using laser-induced breakdown spectroscopy

“…Consequently, due to the proximity of the NG Lewis number to unity, the turbulent burning velocity of NG flames was enhanced, and hence, the stability of the turbulent NG flames in comparison to LPG flames was improved [38][39][40]. Furthermore, the laminar flame speed of the NG/air mixture at lean equivalence ratio of φ = 0.8 was slightly higher compared to that of the LPG/air mixture [41,42]. Therefore, the NG flames were more stable compared to the LPG flames.…”