受限空间内射流影响下主流内气固两相流动实验研究

Experimental investigation of jet influence on gas-solid the two-phase crossflow in a confined domain

为了研究壁面射流在受限空间内对不同粒径颗粒群分布的影响及其作用机理,搭建了横向矩形通道内的射流气固两相流动实验台。通过调整均匀流动段内的隔栅网数量和位置,在无射流条件下使不同粒径颗粒在高度方向上均匀充满整个横向通道。在主流雷诺数7.9×104,射流雷诺数1.8×104的条件下,采用PIV系统对流动通道中的气流场和颗粒分布进行测量。由瞬态涡结构图片发现,带主流受限空间内的射流涡结构与自由射流涡结构具有明显差异,存在不对称的连续涡结构发生、脱落与破裂过程。通过观察射流对不同尺度颗粒的影响,详细分析了射流对颗粒分布发生影响的两大机理,并由此预见了壁面射流控制手段在工程上的应用性。

In this paper,a square horizontal experimental system was built to study the jet influence and its mechanism in a confined domain.Particles of different diameters were used.By adjusting the number and position of the wire meshes in front of the test section,different particles may form a uniform distribution in the symmetrical section without the jet influence.The air flow fields and particle distributions with/without the jet influence were tested by the PIV system.Reynolds numbers for the main flow and jet flow were 7.9×104 and 1.8×104 respectively.The visualization pictures showed that the transient air flow field in the test section was significantly different from the free jet flow field.A serial of vortex occurring,spiraling and breaking phenomena were found in the jet affected flow field in the confined domain.By looking into the motion and dispersion of different diameter particles in the same flow field,two mechanisms were revealed about the jet influence on particle distribution.The wall jet controlling method may have great prospect in the application of particle separator or fluid engineering.