提升管内气固流动的小波分析  

Study on gas-solids flow in riser based on wavelets analysis

作　　者：陈恒志[1] 陈小翠[1] 李洪钟[2] 

机构地区：[1]重庆大学化学化工学院,重庆400044 [2]中国科学院过程工程研究所多相开放实验室,北京100080

出　　处：《化学工程》2009年第8期20-23,共4页Chemical Engineering(China)

基　　金：重庆市科委自然科学基金资助项目(CSTC2008BB6315)

摘　　要：对由光纤探头获得的提升管循环流化床内颗粒体积分数的瞬态信号,采用Dauchveies小波(db4)进行15层的小波分解,并计算各尺度能量分率,以研究提升管底部浓相段与顶部稀相段气固流动结构。结果表明:颗粒速度、体积分数、能量分率在径向分布都呈典型的环核结构;底部浓相段和顶部稀相段的高、中、低频能量分率基本相同,分别在10%,60%,30%左右,说明提升管内大多数的颗粒以聚团形式或密度较大的颗粒群的形式在流化床内流动。操作条件的改变对稀密段气固流动结构的影响不同:颗粒循环流率的改变对密相段的流动影响较大,而气体速度的变化对稀相段的流动影响较大。The solids concentration signals obtained by the optical fiber probe were analyzed by the wavelet analysis method for investigating the gas-solids flow in a riser. These signals were decomposed into 15 scales by db4 wavelet. The results indicate that the velocity, volume fraction and power fraction of the particles in radial distribution all presents a typical core-annular structure, which is uniform in the major portion of the riser, while varies significantly near the wall of the bed. The power fraction of the high frequency, medium frequency and low frequency is about 10% , 60% and 30%, respectively, which implies that the most particles are in the cluster or aggregates in the riser. The influence of the operation conditions on the gas-solids flow strueture in the bottom dense section is different from that in top dilute section of the riser. The solids flux has a visible effect of the gas-solids flow in the bottom dense seetion of the riser, while in the top dilute section, the superficial gas velocity has a significant influence.

关 键 词：提升管 小波变换 能量分布 相结构 

分 类 号：TQ021[化学工程]