Modeling of grease lubrication behavior
Loading...
Authors
Du, Haonong
Issue Date
2025-08
Type
Electronic thesis
Thesis
Thesis
Language
en_US
Keywords
Mechanical engineering
Alternative Title
Abstract
The present research is aimed at building a model from basic fluid mechanics principles, deriving an appropriate modified Reynolds equation, and exploring the behavior of grease in lubrication. Greases are widely applied lubricants in industry. Despite having been used for thousands of years, they are complex substances and the lubrication mechanisms are not well understood. Due to their non-Newtonian behavior, exploration of the properties of grease is more difficult compared with oil-based Newtonian lubricants. Multiple factors can affect the performance of grease in applications. Better models are necessary to simulate the behavior of grease in working environments and to explore the properties of grease itself. The present model is built from fundamental fluid field equations including mass continuity and momentum. The geometry of the journal bearing is used, and the thin film and creeping flow conditions are applied. Multiple additional effects such as body forces, surface properties, elastohydrodynamics and energy balance (thermal effects) are not considered in starting stage of numerical studies. The Bird-Carreau model is adapted to describe the viscosity. With the numerical program, the grease flow is simulated in the geometry of the journal bearing and results predict some behaviors of grease. Pressure distribution is affected by viscosity ratio and length ratio. Eccentricity ratio, length ratio and inlet pressure have effects on load and torque. This model provides a methodology to explore additional properties of grease, and more elements could be added into the model to simulate grease in more complicated environments.
Description
August2025
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY