摘要
以空气和透明玻璃珠为实验介质,对流化床气固两相流的流场进行了实验研究,利用高速摄像机对流化床内气固两相流动进行了拍摄,采用光流法对其流场进行了测定。在实验中,光源的位置、亮度恒定,镜头工况恒定,则检测区域内图像灰度值变化是由流体运动而引起的,故可通过跟踪光流场的变化来检测两相流体的运动场。该方法对数字图像建立整体光流模型,计算出全场像素点的速度矢量,即得到两相流体的速度矢量场。将MQD(最小方差)互相关法与光流法求得的4种典型流型的速度矢量场进行了对比,并用光流法测得的速度矢量绘出其等涡量场,定量上获得了不同流型垂直轴上的上升和下落的平均速度以及总体速度的空间分布特性。实验结果表明:应用光流法比MQD互相关法求出流场更接近实际,而且计算时间短,可以应用于流化床气固两相流流场的检测和流动规律的分析。
With air and glass beads as test medium,a pilot study was performance on the flow filed of gas-solid two-phase flow in the fluidized bed.High-speed camera was used to capture images of gas-solid two-phase flow,optical flow method was adopted to measure its flow filed.In the experiment,the position and luminance of light source was constant.Lens also keeps.Changes of gray value in detecting area were caused by flow movement.Thus,we could measure the flow filed of two-phase flow by track optical flow filed.Overall optical model of digital image was established by the method,speed vector of whole pixel was calculated,and thus,the velocity vector filed map of two-phase flow was acquired.Meanwhile,we have make comparison between two kinds of velocity vector filed maps of 4 typical flow regime which were calculated by MQD（minimum quadratic difference） cross-correlation method and optical flow method respectively.Velocity vector which acquired by optical flow method were used to draw vortex field maps,and quantitative draw space distribution curves of average rising,falling and overall velocity of different flow regime in vertical direction.Experiment result show that flow filed map which acquired by optical flow method is more approach to the reality than by MQD cross-correlation method,and also cost less time.It can be applied to detecting the flow filed map of gas-solid two-phase flow and analyzing its flow rules.
出处
《东北电力大学学报》
2012年第1期7-14,共8页
Journal of Northeast Electric Power University
关键词
气固两相流
图像处理
光流法
MQD互相关法
速度场
Gas-solid two-phase flow
Image processing
Optical flow
MQD（minimum quadratic difference） cross-correlation
Velocity filed
