Radical recombinations in acetylene-air flames

✍ Scribed by P.J.Th. Zeegers; C.Th.J. Alkemade

• Publisher: Elsevier Science
• Year: 1965
• Tongue: English
• Weight: 744 KB
• Volume: 9
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(65)90091-x

✦ Synopsis

In this paper an analysis is given of the behaviour of excess radical concentrations, H, OH and 0 as a function o~ height above the reaction zone in pretnixed acetylene-air +flames at 2-200 ° to 2400°K and I atmosphere pressure. 7['he intensity was measured o/ the Li resonance line which is related to the H concentration through the lithium-water equilibrium. The OH concentration was measured by absorption of the (0,0) band of OH at 3064 Jl. Th~ H, OH and 0 concentrations are related to one another by rapid, binary exchange reactions with stable game molecules. A rather elaborate but complete mathematical expression is derived, which takes into account (i) the four recombination reactions H+H, H+OH, O+O and CO+O, and the reverse reactions; (ii) the variation oJ stable molecule concentrations duc to radical recombination; (iii) the e~[ect of varying temperature on the flame equilibria. I'he experimental results were found to be consistent with theory. By mahing use o/ sow++ additiomd literature data it appeared that the decay of excess radicals in our )qames is mainly governed b¢~ H-[-OI~ and (to a less extent) CO+O recombination. The binary rate constant )or the first'reaction, which was found in this investigation to equcd (I.3+_0.4)X 10 -lacm:%ec-t, agrees ',;c, ith literature d(+ta obtained in hydrogen /larnes. As a side result of this investigation th, ~ dissociation +,nergy o[ LiOH wos ~ound to b~ 110+_,5 heal/tool zc, hich nc~rrows th, uncerlainty in this quantity when ~ombined with two other values reported in the literature.