ERC Researchers Discover Secrets of Fluid Film in Important Pump and Motor Interfaces

Achievement date: 

Researchers affiliated with the Center for Compact and Efficient Fluid Power (CCEFP), an NSF-funded Engineering Research Center (ERC) headquartered at the University of Minnesota, have combined experimental research with advanced  modeling to discover the secrets of fluid film in important pump and motor interfaces.


Thin fluid films separate highly loaded movable pump and motor surfaces from each other and prevent wear and fatal machine failures. Despite many decades of worldwide intensive research, experts and pump designers lack a complete understanding of the complex physical behavior of these thin and critical fluid films. To improve their understanding, the CCEFP researchers created the world’s first fully coupled fluid-structure interaction and multi-body dynamics simulation model, which also considers thermal deformation of main interfaces and their influence on fluid-film behavior. The model will be used to investigate the potential of novel material combinations and specially shaped surfaces to increase load-carrying ability of the film while simultaneously reducing energy dissipation.


Pumps and motors form the heart of every fluid power system. Secrets of the critical fluid films in these systems were revealed when the CCEFP researchers, in a major breakthrough,   discovered the fundamental importance of elasto-hydrodynamic and thermal effects on film generation and film stability (see accompanying figure). Recent research results have proven that these phenomena are responsible for substantial modification of the fluid-film thickness and need to be considered, in addition to micro- and macro-motion effects, to correctly predict fluid-film behavior.