生物质气燃烧稳定性与层流燃烧特性的试验

为了获得沼气的燃烧稳定性与层流燃烧特性,在定容燃烧弹中试验测量了当量比范围为0.7~1.4、初始压力范围为0.1~0.5MPa、初始温度范围为290~380K条件下沼气的层流火焰传播特性。同时,对其燃烧稳定性与层流燃烧速度的主要影响因素进行了分析。结果表明:当层流燃烧速度小于0.15m/s时,火焰在发展过程中将出现浮力不稳定,火核中心逐渐向上飘起。马克斯坦长度随初始压力的升高或当量比的降低逐渐变小,火焰前锋面不稳定性得到增强；初始温度对马克斯坦长度的影响不明显。随当量比的升高,无拉伸火焰传播速度与层流燃烧速度先升高后降低,两者的最大值出现在当量比为1.1时；同时,沼气的层流燃烧速度随初始温度的降低或初始压力的升高逐渐降低。 

Experiment on combustion stability and laminar burning characteristics of biomass gas

In order to gain the combustion stability and laminar burning characteristics of biogas, the laminar flame propagation characteristics of biogas over the equivalence ratio range of 0.7－1.4, the initial pressure range of 0.1－0.5MPa, and the initial temperature range of 290－380K were measured in the constant volume combustion bomb. Furthermore, the main influential factors of the combustion stability and laminar burning velocity of biogas in laminar combustion were investigated. Results showed that the buoyancy instability would appear in the flame propagation process and the flame core would fly upward if the value of the laminar burning velocity was below 0.15m/s. With the increasing of the initial pressure or decrease of the equivalence ratio, the Markstein length decreased and the instability of the flame front increased. However, the effect of the initial temperature on the Markstein length was not obvious. With the increasing of the equivalence ratio, the unstretched flame propagation speed and the laminar burning velocity increased initially and then decreased, and the maximum values were measured at the equivalence ratio of 1.1. Furthermore, the laminar burning velocity of biogas decreased with the decreasing of initial temperature or the increasing of initial pressure.