旋流片开槽深度对低热值煤层气燃烧特性的影响

Influence of the Depth of the Grooves of the Swirling Flow Baffle on the Combustion Characteristics of Coal Bed Gas With a Low Heating Value

为提高低热值煤层气的燃烧效率,设计了3种由不同开槽深度的旋流片组合成的低热值煤层气燃烧器,并进行燃烧特性实验研究,分析了不同流量下,开槽深度对燃烧室内速度、温度及火焰结构特性的影响。研究表明,火焰温度在燃烧器轴线方向分布与流速分布相似,均存在一个温度和速度峰值。相同轴向距离处,甲烷流量减小,3种旋流片的火焰中心流速和温度峰值逐渐下降,且中心流速峰值、温度峰值位置逐渐前移,但温度峰值位置始终是大于速度峰值位置。开槽深度对燃烧特性的影响主要是由于燃气通流截面改变引起的入口流速和射流直径变化导致的。采用3 mm开槽深度的旋流片时,火焰长度和直径增加最快,燃烧室内轴向速度分布和温度场最为理想,射流刚性和火焰充满度最好。

To enhance the combustion efficiency of the coal bed gas with a low heating value,designed were three types of low heating value coal bed gas burner combined by different depths of the groove on the baffle.An experimental study was performed of the combustion characteristics with the influence of various flow rates and depths of the groove on the velocity and temperature inside the combustion chamber as well as its flame configuration characteristics being analyzed.It has been found that the distribution of flame temperature along the axial line direction is similar to that of the flow speed and both have a peak value of temperature and speed.At a same axial distance,the methane flow rate will decrease and the central flow speed of the flame and temperature peak value of the three types of the swirling flow baffle will gradually decrease.In addition,the peak value locations of the central flow speed and temperature will also gradually move forward,however,that of the temperature is invariably greater than that of the central flow speed.When the swirling flow baffle with grooves of 3 mm deep are used,the length and diameter of the flame will increase most quickly and the axial speed distribution and the temperature field inside the combustion chamber will be optimum,thus,achieving an optimum rigidity of the jet flow and an optimum filling degree of the flame.