Development of viscosity measurement using fluorescence spectrum analysis and study on rheological model in lubrication film

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03838
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18040:Machine elements and tribology-related
• Research Institution: Oita University
• Principal Investigator: Otsu Takefumi 大分大学, 理工学部, 准教授 (10634488)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: トライボロジー / 弾性流体潤滑 / レオロジー / 粘度 / 蛍光スペクトル / 転がり－すべり

Outline of Final Research Achievements

In this study, the viscosity measurement technique using fluorescence spectrum analysis was developed and measurements of viscosity profile under rolling-sliding conditions were conducted in order to understand rheological behaviour in elasto hydrodynamic lubrication film. The results showed that the slip ratio affect the viscosity profile, and that under the high slip ratio condition viscosity rising was smaller than that under the rolling condition. In addition, the solidification of lubricant in the contact did not occur due to the high shear action. Moreover, it was indicated by discussion based on Eyring model that even in the high contact pressure the viscosity decreased by the shear action. The measurement technique was improved for applying to various lubricants, such as polyalphaolefin lubricant.

Free Research Field

トライボロジー

Academic Significance and Societal Importance of the Research Achievements

本研究は，潤滑膜内の油の粘度を直接的に測定できる新規的な測定技術を開発したものであり，この測定法の応用により，各種運転条件における潤滑面の粘度分布を明らかとし，当該分野では独自性のある結果となった．特に，すべりが生じる際の油膜厚さの低下について，測定した粘度分布の点から考察することが可能となり，その現象の詳細を理解することに繋がっている．このような結果から，現状の学術的課題となっている油膜内のレオロジーモデルの提案を行うことができ，これらの一連の成果は安全で機能的な潤滑面設計法の構築に貢献し，機械要素の省エネルギー化・長寿命化に寄与するものと考える．