宽粒径分布气粒两相圆湍射流特性研究

Studies on the Characteristics of a Polydisperse Particle laden Round Turbulent Jet

研究了一种宽粒径分布范围的气粒两相圆湍射流的特性。用ρｐ＝ ２ ５９０ ｋｇ／ｍ ３、０～２００ μｍ 的玻璃微珠做颗粒相，实验Ｒｅｙｎｏｌｄｓ 数为５ ６４０，粒气质量比为１５％ 。用粒子动态分析仪（ＰＤＡ）详细测量了两相射流近场（ｘ／Ｄ＜ １５）的流向、径向时均速度、湍动能及颗粒相浓度的分布，分析了Ｓｔｏｋｅｓ数变化对两相射流的影响。结果表明，宽的颗粒相粒径分布削弱了特定Ｓｔ数颗粒与气相的作用。与单粒径分布的两相圆湍射流颗粒相ｕνｐ比气相的ｕν小一个量级的结论不同，在宽粒径分布的气粒两相水平圆湍射流中，颗粒相的湍动能与气相具有相当的量级。

The characteristics of a polydisperse particle laden round turbulent jet have been investigated experimentally.A Particle Dynamics Analyzer (PDA) is used to examine the two phase horizontally exhausting jet and both the single phase and particle laden conditions have been measured.The Reynolds number based on the gas jet exit mean velocity and the nozzle diameter is 5640.Spherical glass beads with a size distribution of 0～200 μm in diameter are used to represent the particulate phase,which have a density of 2590 kg/m 3.Detailed data of the jet including axial velocity,radial velocity,turbulent kinetic energy and the particulate phase flux have been obtained in the downstream of near potential and transitional regions of the jet.Attention is focused of the effect of the variance of Stokes number on the two phase jet.The results show that the interactions between gas phase and particle phase with certain Stokes number have been weakened.The u ν  p of the particle phase is of the same order as that of the gas phase in the polydisperse particle laden jets,while in the monodisperse particle laden jets,the u ν p of the particle phase is smaller than that of gas phase about an order.