用PIV技术研究四角切圆锅炉燃烧器区冷态燃烧流场的湍流积分尺度

四角切圆锅炉内煤粉的燃烧过程对提高锅炉运行效率及NOx减排有着显著的现实意义.通过搭建四角切圆锅炉冷态模型,利用粒子成像测速技(Particle Image Velocimetry),采用空间相关分析方法,针对燃烧器区四角射流复杂湍流的涡拟序结构,开展基于湍流积分尺度来表征的3个典型水平层面涡尺度分布规律研究.通过对湍流积分尺度和时均速度的相关分析研究,认为冷态燃烧器区湍流涡尺度分布不仅与风口流速相关,同时还与风层位置密切相关,并不与风口流速呈线性变化规律,上一次风层涡尺度分布与其它两个风层的相比存在很大差异,因此湍流积分尺度的研究对煤粉高效洁净燃烧具有一定的理论指导意义.

PIV measurements of the turbulence integral length scale on cold combustion flow field in burner zone of tangential firing boiler

The process of the pulverized coal combustion in tangential firing boiler has prominent significance on improving boiler operation efficiency and reducing NOX emission.In this paper,aiming at researching complex turbulent vortex coherent structure formed by the four corners jets in the burner zone,a cold experimental model of tangential firing boiler has been built.And by employing spatial correlation analysis method and PIV(Particle Image Velocimetry)technique,the vortex scale distribution on the three typical horizontal layers of the model based on the turbulent integral length scale(ILS) has been researched.According to the correlation analysis of ILS and the temporal average velocity,it can be seen that the turbulent vortex scale distribution in the burner zone of the model was affected by both jet velocity and the position of wind layers,and was not linear with the variation of jet velocity.The vortex scale distribution of the upper primary air was significantly different from the others.So studying the ILS of turbulent vortex has theoretical significance on high efficient clean combustion of pulverized coal.