摘要
为研究偏心搅拌槽内的宏观不稳定性,基于分离涡模型建立了偏心搅拌数值模拟方法。采用滑移网格法模拟搅拌桨的旋转,实现了偏心搅拌流场的非稳态模拟。对不同工况时的宏观不稳定性进行了频谱分析,讨论了偏心率、雷诺数和桨径比对宏观不稳定频率的影响,并进行了PIV实验验证。研究表明,偏心搅拌槽内存在明显的宏观不稳定现象,其变化周期约为桨叶通过周期的10倍;PIV实验结果与分离涡模拟结果吻合较好,都表明偏心搅拌槽内的宏观不稳定频率随雷诺数的升高而增大,随偏心率的增大而减小,随桨径比的增大而增大。
In order to study the macro-instability （MI） in eccentrically stirred tanks, a numerical simulation method of the eccentric agitation was established based on the detached eddy simulation （DES） model. The impeller rotation was modeled by using the sliding mesh （SM） technique. Utilizing the transient simulation of the flow fields in eccentrically stirred tanks operated under different conditions, the frequency analyses were applied to the time series of the velocity components. The effects of eccentricity, Reynolds number and impeller-tank diameter ratio on MI were discussed and validated by the PIV measurements. Results show that the flow fields in eccentrically stirred tanks are highly unsteady, they are subject to MI with varying period about 10 times the period of the blade passage. Good agreements were found between the DES and PIV results, which indicate that the dominant frequency of MI increases with the increase of Reynolds number and the increase of the impeller-tank diameter ratio, while decreases with the increase of the impeller eccentricity.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2012年第2期228-234,共7页
Journal of Chemical Engineering of Chinese Universities
基金
山东大学自主创新基金(2010GN052)
山东省科技攻关项目基金(2009GG10007019)
关键词
偏心搅拌
宏观不稳定性
分离涡模拟
计算流体动力学
粒子图像测速仪
eccentric agitation
macro-instability （MI）
detached eddy simulation
computational fluid dynamics （CFD）
Particle Image Velocimetry （PIV）
