論文名稱:

振動氣固流體化床粉體流動與混合性質研究

Flow Behavior and Mixing Analysis under

研究生:

柳志鋒

指導教授:

楊士震

          學號:

97017007

畢業學年度:

98

      語文別:

中文

      出版年:

民99

關鍵字:

振動流體化床 vibration gas-solid fluidization bed

最小流體化速度 minimum fluidization velocity

混合 mixing

分離 segregation

摘要:

本研究建立二維振動氣固兩相流體化床設備，探討外部振動與氣流速度對氣固流體化床雙成份粒子混合物流動行為以及混合與分離效應的影響，配合壓力量測與高速攝影系統，觀測粒子流體化行為、氣泡形成與壓力擾動特性，實驗結果顯示振動氣固流體化床粒子流體化與混合/分離機制受到空床氣速、粒徑大小比、靜床高度、組成粒子濃度及振動強度(振動加速度、振動頻率、振幅)影響，在相同氣速時，由於振動力的作用，振動流體化床之床體壓力降較固定式流體化床低，最小流體化速度與床層孔隙度變小，當振動強度較小時，床層粒子受氣流影響較大，小粒子集中在床體上層，大粒子則集中在下層，呈現分離流動現象，隨著振動強度增加，粒子間運動較為激烈，呈現混合運動狀態。關鍵詞：振動流體化床、最小流體化速度、混合、分離

This research established a vibrated gas-solid fluidized bed equipment to investigate the flow behaviors and segregation/mixing phenomena of binary granular mixture with the effect of external vibration and superficial velocity. The pressure transducer and highresolution camera system are used to observe the fluidization, bubbling and pressure fluctuation characteristics of the binary mixtures. The experimental results showed that the fluidization and segregation/mixing mechanism of granular mixture are affected by gas velocity, particle size ratio, static bed height, composition concentration and vibration conditions (vibration acceleration, vibration frequency and amplitude). As the gas velocity keeps constant, the pressure drop for vibrated fluidized bed is lower than that of fixed fluidized bed. In addition, the minimum fluidization velocity and porosity is decreased. For smaller vibration intensity, the small particles concentrated the upper region and the large particles move to the lower region of the bed. In the mean time, the segregation phenomenon forms. As the vibration intensity increases, the movement of particles is active and the mixing is present in the vibrated fluidized bed.