添加氢气对LPG/空气预混火焰结构的影响

针对氢气添加的LPG(液化石油气)+空气预混火焰结构进行了数值研究, 详细计算了在含氢比a为0%到45%、稀释引子D为21%到16%条件下的自由蔓延火焰, 得到了不同燃烧条件(φ=0.7-1.4)下的绝热燃烧速率变化规律. 由于LPG中的主要成分为丙烷和丁烷, 作者针对C3和C4物质提出了详细化学反应动力学系统, 并针对氢气添加的丁烷燃烧过程进行了数值计算, 得到了与实验相一致的结果, 验证了改进的详细化学机理的有效性. 此外, 进一步计算了对撞双火焰的加氢LPG火焰, 更加深入地探讨了火焰拉伸对燃烧稳定性和温度的影响, 重点研究了φ在0.5到0.7的稀薄燃烧, 验证了氢气添加可以有效提高稀薄燃烧条件下熄火拉伸率, 扩大稀薄燃烧的极限, 增加火焰的稳定性.

Effects of Hydrogen Enhancement in LPG/Air Premixed Flame

A numerical study of hydrogen-enhanced liquefied petroleum gas (LPG)+air flames was presented.The variations of the adiabatic burning velocity in different conditions of combustion(φ=0.7-1.4)were studied extensively.The hydrogen content in the fuel was varied from 0% to 45% and the dilution factor was from 21% to 16%.Since the major components of LPG are butane and propane.an appropriate chemical kinetic model must be chosen to solve the chemical reaction of C3 and C4 species.Validation of the chemical kinetic model against the fundamental combustion data was performed to insure accuracy.In addition,independem simulations were conducted in the opposed-jet,symmetric,twin-flame configuration.The effects of fluid mechanics,as manifested by the induced strain rate,were also considered.The effects of extinction strain rate on flame temperature and the fiammability limits were calculated and the results showed that hydrogen-enhanced LPG/air premixed flames were more stable at high flame strain.The lean flammability limits were extended by the H2 addition.