摘要
基于对混合时间定义的思考,提出了一种新的定义方法,在湍流流场数值计算的基础上通过求解示踪剂的浓度输运方程,研究了单层涡轮桨搅拌槽内的混合过程。结果表明:搅拌转速和搅拌桨安装位置都影响混合时间的大小,而进料位置对混合时间的影响不大。对于不同的搅拌转速而言,随搅拌转速的增大,相同体积分数对应的混合时间逐渐减小。当搅拌桨安装在槽中间位置时所对应的混合时间最小。利用适宜的尺寸和安装位置的导流筒可有效降低混合时间。
A new definition of mixing time was proposed based on the fraction of well-mixed volume. The mixing process in the stirred tank with a single Rushton turbine was examined by solving the transport equation of the tracer based on the numerical simulation of the whole flow field. It was shown that the value of mixing time was dependent on the speed and position of impeller. Mixing time decreased with the increase of impeller speed at the same volume concentration. When the impeller was in the center of the tank, the mixing time was the shortest. The draft tube with proper dimension and position could effectively decrease mixing time.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2007年第8期1891-1896,共6页
CIESC Journal
基金
国家自然科学基金项目(20236050
20306028
20576133)
国家重点基础研究发展计划项目(2004CB217604)~~
关键词
混合时间
计算流体力学
搅拌槽
Rushton桨
mixing time
computational fluid dynamics （CFD）
stirred tank
Rushton impeller
