Analogy between heat and flow of drag-reducing surfactant aqueous solution based on relaxation time

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K21931
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 19:Fluid engineering, thermal engineering, and related fields
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Tamano Shinji 名古屋工業大学, 工学(系)研究科(研究院), 教授 (40345947)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 抵抗低減 / 界面活性剤 / 粘弾性流体

Outline of Final Research Achievements

To clarify the analogy between the drag reduction (DR) and the heat transfer reduction (HTR) of a nonionic surfactant aqueous solution in pipe flows, the pressure loss and flow rate were measured for the DR measurement, while the fluid temperature and pipe outer wall temperature were measured for the HTR measurement. It was found that the DR and HTR as a function of the Reynolds number were similar to one another, but the DR was smaller than the HDR under the present experimental condition. In addition, we performed the PIV measurements of turbulent pipe flows with and without surfactant injection. For the case of without injection, we found that the mean streamwise velocity profile was modified according to the amount of drag reduction, and the Reynolds shear stress was almost zero at the high drag reduction. For the injection case, it was revealed that the drag reduction ratio approached that of homogeneous surfactant solution in the streamwise direction.

Free Research Field

流体工学、レオロジー

Academic Significance and Societal Importance of the Research Achievements

配管系の流動抵抗を低減することができれば、ポンプ動力を削減することが可能となり、省エネ化に繋がる。本研究成果は配管系でしばしば用いられる円管内の流れに抵抗低減剤として界面活性剤を注入した際の抵抗低減効果を明らかにしたものである。本研究では、界面活性剤水溶液を壁面近傍に効率よく注入することにより、下流域において一様な界面活性剤水溶液の場合と同程度の高い抵抗低減効果を得られることを明らかにしている。抵抗低減界面活性剤の効率的な使用法が確立されれば、さらなる省エネ化に繋がるものと期待される。（246文字）