粘弾性多層流における液膜表面形状形成に対する数値解析を用いた評価法

抄録

In this study, we examined to clarify main factor that affect to the liquid film surface appearance for multilayer flow that consisted of polymer solution of different rheological behavior. The correlation of the viscoelastic flow behavior in the three-layer channel and the liquid film surface appearance was examined by numerical analysis. As the results, the following technical findings were obtained. (1) The first normal stress difference generated in the sub-fluid, which was a main factor for the generation of the surface irregularity was large at the vena contracta and the merging part. However, the main factor for the generation of the surface irregularity was the first normal stress difference generated in the sub-fluid at the vena contracta. Because the first normal stress difference generated in the sub-fluid at the merging part was perfectly relaxed in the channel. (2) The factor analysis between layers was conducted to specify the main factor for the generation of the surface irregularity. As the result, it was understood that there is a strong correlation between the frequency of the surface irregularity and the force to act on the sub-fluid around the interface at the vena contracta (F_s). Moreover, it was understood that there is a correlation between F_s and the interfacial roughness (R_a-int) of the distance at the vena contracta to the discharge part. (3) Sharping the inflow angle and chamfering the inflow corner are effective to the reduction of the force both to act on the sub-fluid around the interface and to control the generation of the surface irregularity.