On the Initiation of a Spherical Flame Kernel
On the Initiation of a Spherical Flame Kernel
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DOI：
10.1080/00102208408923749
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发表时间：
1984-05
影响因子：
1.9
通讯作者：
B. Deshaies;G. Joulin
中科院分区：
文献类型：
--
作者：
B. Deshaies;G. Joulin
利用反应速率大活化能的匹配渐近展开式，我们研究了稳定的球形预混火焰的结构和稳定性，在这种几何形状下，不需要任何源(或汇)的新鲜(或燃烧)气体的支持。这种无支撑火焰的半径强烈地依赖于热和反应物的微分扩散，并被解释为与不稳定平衡相对应的火焰起燃判据。必须超过这个半径，火焰才能向外自我传播。然后我们将注意力集中在两种方法上来改变甚至抑制这样的临界火焰尺寸，即：(I)恒定功率的中心治疗源的影响，以及(Ii)添加少量具有大分子扩散系数的类氢反应物种。多个稳定的解决方案--包括稳定的、不传播的火焰--或平衡解决方案的消失，以及火焰动力学的质的变化。
Abstract Using matched asymptotic expansions for large activation energies of the reaction rates, we have studied the structure and stability properties of steady spherical premixed flames which, in this geometry, need not be supported by any source (or sink) of fresh (or burned) gases. The radius of such unsupported flames strongly depends on the differential diffusion of heat and reactant and is interpreted as a flame initiation criterion which corresponds to an unstable equilibrium. This radius must be exceeded for the flame to self-propagate outward. We then focus attention on two means to modify, or even suppress, such a critical flame size, viz.: (i) the effect of a central heal source of constant power, and (ii) the addition of small amounts of a hydrogen-like reactive species with large molecular diffusivity. Multiple steady solutions-including stable, non-propagating flames-or the disappearance of equilibrium solutions are exhibited as are qualitative changes in flame dynamics.