气固两相流颗粒相特性参数的测量及其不确定分析

Measurement and Uncertainty Analysis of the Particle Phase Characteristics in a Gas-Solid Flow

本文介绍一种采用光纤式高速摄影测量装置获取三维柱锥形冷态喷动床试验台内部气固两相流颗粒瞬时速度的测量方法、及其测量不确度的分析。基于获取的颗粒相运动视频,计算出颗粒瞬时速度、颗粒相速度和颗粒温度,它们分别用于表征测量区域中颗粒群流动的快慢和脉动的强弱。测量结果表明:镜头畸变校正环节是影响颗粒瞬时速度测量的主要因素,本测量装置的颗粒瞬时速度的测量不确定度为士2.383%;颗粒相速度在喷泉核心区(r/R≤0.2)为正,绝对值较大,沿半径方向减小到零,然后在r/R=0.45处转变方向并逐渐增大;颗粒温度在区域r/R≤0.2和r/R≥0.65变化显著,对应着喷动床内颗粒喷射上行和下落的主要区域,这证实了公开文献中喷动床内颗粒脉动动能分布的数值模拟结果。

A fiber high speed photography measurement system based on image processing technique has been applied to obtain the flow characteristics in a 3D cylindrical spouted bed. Statistical analysis and multi-scale wavelet decomposition have been employed to investigate the complex dynamic parameters contained in the measured gas-solid flow signals. The experimental results show that the measurement uncertainty for particle velocity is mainly due the endoscopic distortion and its overall value is about =t=2.3% in the experiments. The profile of particle phase velocity shows that particles exhibit different flow patterns along the bed radius. Basically, particle phase velocity in the region （r/R≤0.2） is positive and decreases along the radial direction till it reaches zero at the position r/R=0.45. After that, it will be negative and increases gradually. As for the granular temperature, it varies strongly in the regions in r/R≤0.2 or r/R≥0.65. These results certificate the phenomena suggested by other published numerical papers.