摘要
提出一种适用介质粘度范围广的新型内外组合搅拌桨。利用计算流体力学和粒子图像测速技术对该搅拌桨产生的流场进行研究。考察不同工作介质、不同转速比情况下,带有新型内外组合桨的搅拌设备内的时均速度、速度变化率和剪切速率分布。结果表明:新型内外组合搅拌桨在各个方向产生的流动都比较剧烈,其径向速度和轴向速度的分布与内外桨转速比密切相关。采用新型内外组合桨改善了搅拌设备近壁区的流动状况,改善程度随着转速比的减小而增强,且对假塑性流体流动状况的改善优于牛顿流体。新型内外组合搅拌桨改善了整个搅拌设备内尤其是近壁区的剪切水平,并且改善程度随着转速比的减小而显著增大。
A novel combined inner-outer agitator, which is applicable to working medium with different viscosities from lower to higher, is proposed. The computational fluid dynamics and particle image velocimetry technique are adopted to investigate the flow field stirred by this novel combined agitator. Under the conditions of different working medium or rotating speed ratios between the inner agitator and outer, the mean velocity, rates of the velocity change and shear rate in stirred vessel with this novel agitator are analyzed. Results show that the flow produced by the novel combined inner-outer agitator is dominated by all the three velocity components, and the distributions of radial and axial velocities changes closely depending on the rotating speed ratio. Using the novel combined agitator, the flow fields near the vessel wall can be improved. The improvement level increases with the decreasing rotating speed ratio, and it is better for the pseudoplastic fluid than the Newtonian fluid. The novel combined inner-outer agitator enhances the shear strength in the stirred vessel, especially in the regions near the vessel wall, and the amplification increases with the decreasing rotating speed ratio.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2007年第11期56-62,共7页
Journal of Mechanical Engineering
基金
上海电机学院上海市重点(培育)学科机械制造及自动化基金。
关键词
新型内外组合搅拌桨
流场
数值模拟
粒子图像测速
Novel combined inner-outer agitator Flow fields Numerical simulation Particle image velocimetry
