外旋流器旋流数对三级旋流流场特性的影响

采用二维粒子图像测速(2D-PIV)流场测试技术,试验研究了相同进口条件下多种旋流数组合旋流器出口冷态流场,分析比较了外级旋流器旋流数对流场结构的影响.研究结果表明:外级旋流器旋流强弱并不是回流区形成的主要决定因素；随着外级旋流器旋流数的增加,涡心有向前及向外移动的趋势,其回流区轴向长度逐渐变长,最大回流速度逐渐减小；回流区形状同时受外级旋流器旋流数及内级旋流器旋流数的影响,当外级旋流器旋流数相对内级旋流器旋流数足够大时,较易出现尾迹区；在旋流器出口附近,外级旋流器旋流数较小时旋流器组合流场的湍流强度峰值较大. 

Effects of outer swirl number on flow characteristics of triple swirlers

The two dimensional particle image velocimetry (2D-PIV) planar structure was utilized to measure the flow field of different triple swirlers under the same inlet condition, helping to analyze the effects of outer swirl number on flow characteristics. The experimental results show that: the swirl intensity of outer swirler is not the critical factor for the formation of central toroidal recirculation zone (CTRZ); the increment of CTRZ length, recirculated mass flowrate ratio, and the decrement of maximum recirculated velocity correspond to the increment of outer swirl number, as the cores of the vortexes move upward and outward; the shape of CTRZ is affected by both outer and inner swirl numbers, and an obvious CTRZ tail can be obtained for swirler with higher outer swirl number; a higher turbulence intensity of the flow generated by triple swirlers with lower outer swirl number occurs near the swirler exit.