管内流れの乱流遷移に及ぼす界面活性剤添加の影響(流体工学,流体機械)

概要

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The effect of drag reducing surfactant (C_<14>TABr) additives on the transition in pipe flow has been investigated through pressure drop measurement, LDV measurement and flow visualization. The experiment was carried out using the glass tube of diameter D=5.02mm and D=2.61mm. Two types of flow were experimented upon: the flow that decreased background-turbulences as much as possible and the flow that was disturbed by a ring-shaped roughness element. In the flow of the former, the following was understood: within the range from Re=3000 to 4500, a temporary rapid increase in the friction factor appeared although the flow was quasi-laminar. In a concentration that exceeds 400 ppm, a turbulent transition happened gradually and vaguely, not drastically as Re increased. In the flow of the latter, the following was understood: although in the case of water a turbulent patch generated in the initial stage of the transition in Re>2450 was a turbulent slug, the present study suggests that in 260 ppm, the turbulent puff was generated in the initial stage of the transition in Re=3500. Furthermore, turbulent patches were not generated in the concentration above 400 ppm.
一般社団法人日本機械学会の論文
2006-05-25