多层桨搅拌槽内非常温体系局部气含率分布

引　言局部气含率是气 -液分散的重要特征参数 ,它广泛应用于反映器的分析、选择及设计 .局部气含率与槽内的流型密切相关 ,它能够反映槽内局部的分散及传质特性 ,因此受到研究者的广泛关注[1] .由于受测试手段的限制 ,仅有部分学者对常温下单层桨通气搅拌槽进行了研究[2～ 6] ,而对于工业中广泛应用的多层桨搅拌槽则研究甚少 .许多工业过程是在较高的温度下进行的 ,而已有的研究几乎都是在常温下进行 ,忽视了液体的温度对气 -液两相体系流体力学性能的影响 .常温下的气 -液分散体系 (气体 -常温液体 )主要常见于耗氧性生物发酵、水处理等工…

LOCAL GAS HOLDUP DISTRIBUTIONS IN NON-AMBIENT STIRRED TANKS WITH MULTIPLE IMPELLERS

Vertical gas holdup distributions in ambient gassed, hot sparged and boiling systems in stirred tanks using multiple 6 hollow blade disc turbines(CD-6)are reported.The local gas holdup in the boiling system is dramatically different from that in the ambient gassed or hot sparged system whether in terms of value or distribution.Under the same total gas flow rate and impeller speed,the local gas holdup is much smaller in the boiling system than that in the ambient gassed or hot sparged system.The hot sparged system has similar vertical gas holdup distributions,with maxima in similar locations but with smaller local gas holdup overall,to those of the ambient gassed system.The designs of existing hot sparged and boiling reactors are based on the ambient gassed system and not optimal.The results are of particular relevance to the design and operation of reactors with hot sparged or boiling liquids.