火焰筒扩张角与旋流匹配对燃烧特性的影响

Influence of Flame Tube Expansion Angle and Swirl Matching on Combustion

火焰筒头部结构对预混燃烧性能有重要影响,为了探讨旋流器与火焰筒扩张角相互作用关系,试验研究了扩张角为35°(渐扩)、90°(突扩)的火焰筒分别匹配旋流数为0.55,0.75旋流器对燃烧性能的影响。试验结果表明:渐扩火焰筒总压损失较突扩火焰筒减小约3.4%~4.4%,且匹配较小旋流数具有更高的总压恢复系数;突扩火焰筒较渐扩火焰筒具有更低的贫油熄火极限,且无论突扩火焰筒还是渐扩火焰筒,匹配较大旋流数旋流器后均具有更低的熄火极限;突扩型火焰筒温度场对旋流器适应性好,各旋流数下均获得较均匀温度场,出口温度分布系数为0.1341~0.1416;渐扩火焰筒温度场对旋流器适应性差,匹配较小旋流数旋流器后温度场均匀性更好,出口温度分布系数为0.1357;突扩火焰筒NOx排放量更低,且匹配小旋流数旋流器更佳;渐扩火焰筒CO和碳氢化合物(UHC)排放更低,且匹配大旋流数旋流器更佳。

The structure of flame tube head has an important influence on premixed combustion performance.In order to explore the interaction relationship between swirler and flame tube expansion angle,the effects of 35°gradual expansion and 90°sudden expansion flame tube head matching swirl number(SN)of 0.55 and 0.75 respectively on combustion performance are experimentally studied.The test results show that the total pressure loss of the flame tube with 35°expansion angle is reduced by about 3.4%to 4.4%compared with that with 90°expansion angle,and the total pressure recovery coefficient is higher matching smaller SN;the 90°expansion angle flame tube has a lower lean oil flameout limit than the 35°expansion angle,and both 90°and 35°flame tubes have a lower lean oil flameout limit when matching larger SN;the outlet temperature field of sudden expansion flame tube has good adaptability to the swirler,a more uniform temperature field can be obtained at each SN,and the outlet temperature distribution factor(OTDF)is 0.1341 to 0.1416;the outlet temperature field of gradual expansion flame tube has poor adaptability to the swirler,but the temperature field uniformity is better with smaller SN,and the OTDF is 0.1357;NO_x emission of sudden expansion flame tube is lower,and it is better to match small SN;CO and unburned hydrocarbon(UHC)emissions of gradual expansion flame tube are lower,and it is better to match large SN.