摘要
基于混沌混合理论,提出了一种错位叶片的结构形式,用来消除层流流场的混合隔离区。利用CFD的方法,对六弯叶涡轮(6BT)和错位六弯叶涡轮(6SBT)2种搅拌器在黄原胶水溶液中的流场变化进行研究,分析比较了2种搅拌器的流场结构、速度分布以及功率消耗的不同。结果表明,模拟计算得到的功率值与实验测量值吻合较好,6SBT桨在层流区的临界雷诺数为20;错位叶片搅拌流场结构不对称,可消除流场隔离区,搅动范围变大;随Re增大,对层流流场的改善效果增强,全槽的平均剪切速率得以提高,并且具有节能功效。在转速N=5 r/s的条件下,6SBT桨的轴向和径向速度分布整体上明显好于6BT桨,而功耗约为6BT桨的93%。
Based on the chaotic mixing theory,a novel impeller with shifted 6-bent-blade was proposed for destroying the mixed isolation region of laminar flow field.Computational fluid dynamics（CFD） method was applied to the study of 3D flow field driven by a 6-bent-blade turbine（6BT） and a shifted 6-bent-blade turbine（6SBT） respectively in the agitation of xanthan gum.The flow pattern,mean velocity distribution and power consumption in stirred tank with two different impellers were extensively analyzed and compared.The results show that the values of numerical simulation and the experimental measurement of power consumption are in good agreement,and the critical Reynolds number of 6SBT in laminar flow is 20.The asymmetric structure in flow field of 6SBT can destroy mixed isolation region,and enlarge the stirring range.The improvement effect of laminar flow field performance strengthens,the average shear rate increases,and it has energy-saving effect as Reynolds number increases.The radial and axial velocity distributions of 6SBT are clearly superior to those of 6BT at agitation speed of 5 r/s,while the power consumption is about 93% of that in 6BT agitation.
出处
《化学工程》
CAS
CSCD
北大核心
2011年第9期41-46,共6页
Chemical Engineering(China)
关键词
假塑性流体
错位六弯叶桨
隔离区
层流模型
pseudoplastic fluid
shifted 6-bent-blade turbine
isolation region
laminar flow model
