Physical and chemical effects of phosphorus-containing compounds on laminar premixed flame

Phosphorus-containing compounds are the promising halon alternatives for flame inhibitions. However, some literatures suggested that the phosphorus-related inhibitors may behave as the unfavorable ones that will increase the burning velocity under lean-burn conditions, and this indeed posed potential threats to the fire prevention and fighting. To seek deeper insights into the reaction process, a numerical investigation was actualized to study the phosphorus-related effects on methane-air flames. By replacing a phosphorus-related inhibitor with the corresponding decomposed molecules, the detailed promoting and inhibiting effects of combustion were separated from the general chemical effect. A comparative study was carried out to identify the interaction between the two effects under different combustion conditions. It is observed that the promoting effect becomes the dominant factor during the reaction process when the equivalence ratio is smaller than 0.60. In this lean-burn condition, the exothermic reactions were faster than the others within the reaction chains due to the reduction of radical recombination in hydrocarbon oxidation. The results are believed to be useful for the further application and improvement of flame inhibitors.     

浮力扩散火焰对低频外加声场的响应特性

本文通过实验研究了浮力扩散火焰在外加声场作用下的响应行为和熄火机理.实验发现,声场中的气体燃料火焰熄火时,火焰处的声压与声频呈正相关.但该正比关系受火焰和环境等因素影响,无法精确判断熄火的临界条件.因此,本文基于火焰在声场中的偏移量脉动,为声场的临界灭火条件构造了数值判据.研究结果表明,该判据对目标火焰的依赖性较低,且...