环空管内粘弹性流体不定常旋转流的解及流动特性分析
An Analytical Solution and Analysis of Characters for Viscoelastic Fluid Flow in Annular Pipe
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摘要: 本文用Hankel积分变换法分别求得二阶流体和Maxwell流体在环管内不定常旋转流运动方程的解析解,据此可以分析环管内旋转速度和切应力的分布与变化特征;流体物性参数、管道环隙大小等参量在解析公式中有明确反映,便于定性分析和讨论,本解可以为钻探工程和高分子加工工艺的设计提供理论依据,另外还可用来分析双筒粘度计的流动状态和应力特征,拟合曲线,确定材料的粘弹性参数,在对这种流体进行特性分析时,我们发现,Maxwell流体的旋转流动在起动初期表现为方波振荡,振动的幅度和周期随Ha(物质常数)的增大而增大,此种现象还是首次发现,可能对实际应用有一定的意义。Abstract: In this paper an analytical solution to flow of second order and Maxwell fluid in annular pipe by using Hankel integral transform is presented A derived formula can be used to analyze the behavior of rotatory velocity and shear stress: since the parameters of material and the gap size of annular pipe explicitly appear in the analytical formula one can easily analyze their effection on the flow behavior. This solution can provide a theoretical base to drilling engineering and polymer shaping techniques. In addition, it can be used to analyze the flow characters in concentric cylinder rheometer and obtain material constants with curve fitting procedure.By investigation it is found that when outer cylinder makes uniform rotatory the history curve of velocity and stress of Maxwell fluid exhibit obliquerectangle wave and rawwave oscillation respectively. The wave period and amplitude increase with material constant Ha. This conclusion may be of significance in practice.
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Key words:
- viscoelastic fluid /
- annular pipe /
- analytical solution
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[1] 刘慈群、黄军旗,非牛顿流体管内不定常流的解析解,应用数学和力学,10(11) (1989),939-946. [2] 朱文辉、刘慈群,Maxwell流体环管不定常流动解析解,力学学报,24(1) (1992). [3] 韩式方,《非牛顿流体连续介质力学》,四川科学技术出版社(1987). [4] I .Sneddon, Fourier Transform, New York-Toronto-London (1951). [5] M,N.奥齐西克,《热传导》,俞昌铭主译,高等教育出版社(1989).
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