气固两相圆湍撞击流的POD结构分析

Analysis of Turbulent Coherent Structures in Round Particle-Laden Opposed Jets Based on POD Method

本文使用本征正交分解方法(POD)对雷诺数Re=14500,喷嘴间距L/d=5、12的气固两相撞击流进行了PIV实验研究,颗粒相采用平均直径100μm的玻璃珠,质量载荷Φ_m=2%。研究结果表明:两种间距下撞击流的1阶模态结构相似,为分布在撞击中心两侧径向上的反向涡对结构;其他阶(2～4)模态结构为径向射流上的由主导涡诱导形成的一组涡系结构;颗粒的加入增强了轴向射流区轴向湍流脉动结构,破坏了撞击流有规律的涡系结构。

Proper orthogonal decomposition（POD） was used to investigate the turbulence coherent structures of particle-laden opposed jets.The Reynolds number is 14500,and the nozzle spacing L/d is 5.12.Glass beads with the diameter of 110 urn are used as dispersed phase,and mass loading ratio ofΦ_m=2%is tested.The results show that there is a symmetrical reverse vortex pair structure on the radial jet region in the 1st POD mode of opposed jets.The other modes（2～4） are a series of vortex structures,which was formed by a lead vortex on the radial jet.It was found that the particles enhanced the axial fluctuation velocity on the axial jet region,and broken the coherent structures of opposed jets.