循环流化床环核结构速度分布PIV测试

利用粒子图像测速仪（PIV）对循环流化床中颗粒流场进行了系统的实验研究。运用适合于高粒子浓度的最小方差法（MQD）图像处理算法得到了截面内典型环核流动颗粒速度矢量场。采用速度矢量场的方法可以确定出环核结构分界。定量上获得了不同时刻颗粒轴向上升和下落平均速度大小及沿床径向分布特性。在统计颗粒轴向上升速度和下落速度代数和基础上，获得了总体上颗粒轴向速度沿床径向在整个截面内形成抛物线型的环核分布规律。

Particles velocity distribution of the gas-solids flow field in the circulating fluidized beds by PIV

Particle Image Velocimetry(PIV) was used to investigate particle velocity field in a riser of gas-solid circulating fluidized bed.By the Minimum Quadric Difference(MQD) cross-correlation algorithm suitable for high density of particles,the particle velocity vector fields with time were obtained.The interface of core-annulus flow may be determined with the particle velocity vector fields.It was also obtained for the magnitude of axial velocity upward and downwards with time.The results showed the parabola characteristics of the velocity distribution and the core-annulus flow about solid particles along the whole cross-section in the circulating fluidized beds.