Clarification of Factors on Friction Reduction between Granular Materials and Walls with Ultrasonic Vibration

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05129
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 27010:Transport phenomena and unit operations-related
• Research Institution: Nihon University
• Principal Investigator: KOFU Kenji 日本大学, 理工学部, 准教授 (10424748)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 超音波振動 / 粉粒体 / 摩擦低減効果 / 粒子径 / 振動板サイズ

Outline of Final Research Achievements

In order to clarify the factors affecting on friction reduction effect between particles and wall by ultrasonic vibration, the amount of friction reduction by ultrasonic vibration was measured while the material and size of cube and vibration plate size were changed. This experimental result showed that the friction reduction increased as the vibration amplitude increased in spite of conditions. Then, the reduction was enlarged as cube size is small and vibration plate size is large. Additionally, this reduction effect also depends on the material of cube. The deformation of the cubic material was measured using a laser Doppler vibrometer, and it was revealed that the tendency of this deformation agrees with friction reduction effect. Therefore, it could be showed the deformation is the main factor for friction reduction. Finally, acoustic streaming effect was also investigated. As a result, this velocity is so slow, and it is concluded as acoustic streaming effect can be neglected.

Free Research Field

粉体工学

Academic Significance and Societal Importance of the Research Achievements

レアメタルなど製品に使用されている材料をリサイクルする必要があり，既に幾つかその方法が研究され，提案されている。しかし，既存手法では単一の物性差を利用するため，近い粒子同士の分離は困難である。本研究テーマに関係する超音波法は複数の物性値が影響するため，既存手法で困難であった組合せの粒子群に対して活用できる可能性がある。また，流動化法など既存手法と組み合わせることで，例えば最小流動化速度の低減による省エネ化や分離精度向上に貢献できる可能性がある。