急縮小流路における高分子流体の三次元可視化実験と流動解析
Three-dimensional Flow Visualization and Numerical Simulation of Polymer Solution through Abrupt Contraction
温 洪昭・中村喜代次
Wen, Hongzhao / Nakamura, Kiyoji
A three-dimensional flow visualization of a polyacrylamide/corn-syrup aqueous solution was carried out, using a 2.5 : 1 abrupt contraction with 3 : 1 aspect ratio. A numerical simulation of three-dimensional flow was also carried out with an Oldroyd-B model in the same geometry. The numerical results were compared with the visualization results.
The experiment shows that a lip vortex takes place near the front wall at a low flow rate, but is not observed near the central part of the lip corner at the same flow condition. The lip vortex then develops with increasing flow rate into a larger corner vortex. Under the experimental conditions of the present paper, the lip vortex has an important influence on the development of vortex enhancement in the 3-D abrupt contraction. For some combinations of rheological parameters, the numerical results agreed qualitatively with the experimental results.
Key words: 3-D contraction flow / Rip vortex / Oldroyd-B model / HSMAC method