CAJ | 학술논문

气体物性对流化床中流体结构有着重要影响，是流化床反应器设计和放大的关键参数。本文应用基于细网格的双流体模型，研究了不同气体作为流化介质在不同气速下对流化床中固体浓度分布以及床层膨胀高度的影响。研究结果表明，气体密度和粘度的增大有利于均匀流化；气体的粘度相对于密度对流动特性的影响更为重要。在本文的模拟条件下，随气速增大不同气体流化的床层膨胀高度增加程度较为接近。模拟结果还直观的展示了鼓泡流态化中典型气泡的运动和形变过程，并结合对气泡附近的气体和固体流场的分析，讨论了气泡运动过程中气体内部之间和气体与固体之间的质量交换行为。
기체물성대류화상중류체결구유착중요영향，시류화상반응기설계화방대적관건삼수。본문응용기우세망격적쌍류체모형，연구료불동기체작위류화개질재불동기속하대류화상중고체농도분포이급상층팽창고도적영향。연구결과표명，기체밀도화점도적증대유리우균균류화；기체적점도상대우밀도대류동특성적영향경위중요。재본문적모의조건하，수기속증대불동기체류화적상층팽창고도증가정도교위접근。모의결과환직관적전시료고포류태화중전형기포적운동화형변과정，병결합대기포부근적기체화고체류장적분석，토론료기포운동과정중기체내부지간화기체여고체지간적질량교환행위。
The gas properties have important effects on the flow structures in a fluidized bed and are key parameters for design and scale-up of fluidized bed reactors. In this paper, two-fluid model using fine grids was adopted to investigate the effects of gas properties under different velocities on the solid concentration distribution and the bed expansion height. The simulation results showed that the increasing of gas density and viscosity led to homogenous fluidization while the gas viscosity was more important to flow characteristics compared with gas density. Under the simulation conditions, the bed expansion heights fluidized by different gas increased to similar extent with the increasing of gas velocity. The simulation results also visually illustrated the process of a typical bubble’s motion and deformation in the bubbling fluidization. Integrated with the analysis of flow field around a bubble, the mass transfer in gas as well as between gas and solid during the bubble’s motion was discussed.