Welcome to Super Polymer Bearings (SuperPolB) website
Over the past two decades, there has been a demanding and growing request for redesigning mechanical systems and applications in a more efficient, more durable, and more environmentally friendly way. Given its importance in fundamental fields, like oil & gas, aeronautical propulsion, transport engineering, a crucial area is related to turbomachinery and, thus, to the development and optimization of rotating machines. In this context, a decisive role is played by the oil-filled fluid dynamic bearings that support the machine and deeply influence its efficiency. Unfortunately, these bearings are currently marked by poor performances in terms of friction, wear and thermal resistance, and durability.
The SuperPolB project will address these issues by developing high efficiency fluid dynamic journal bearings: these will feature polymer coatings with an innovative surface micro-texture designed to optimize the tribological performance of the bearing. The very ambitious goal of the project will be pursued through the unique combination of numerical and experimental techniques guaranteed by the research consortium including Politechnic University of Bari (PoliBA) and University of Florence (UniFI).
Numerical analyses and simulations
Optimization of tribological performances of the polymer journal bearing
The goal
Numerical optimization of tribological performances of the polymer journal bearing.
The specific aim of the numerical optimization is to enhance the global efficiency of the bearing by acting on both the loading capacity and the local friction forces. The loading capacity must be carefully considered not only to guarantee the operating performance of the bearing, but also specifically to obtain, even at low velocities, a full-film lubrication, thus reducing the occurrence of boundary lubrication conditions as much as possible. On the other hand, the diminution of the shear stresses may directly act on the energy dissipation. Clearly, these two aspects, that is, load capacity enhancement and shear stresses reduction, may be in contrast and a balance should be reached in the optimization. Finally, the viscoelastic hysteresis in the solid should be limited.
Validation and testing
Experimental Measures
Concerning the experimental methodology of the research project, two important problems must be faced up: the validation of the multi-physics models of the polymer bearing involving thermo-viscoelastic-hydrodynamic lubrication (TVEHL) and the verification of the polymer bearing efficiency, wear and performance (both thermal and dynamic).
All this measurements are carried out on the highly accurate test rig available at the University of Florence, where an extremely large set of forces and speeds may be tested.
Specific Research Objectives
Objective SO1
How can Thermo-visco-elastohydrodynamcis lubrication (VEHL) be modelled coupling lubricant dynamics with mechanical and thermal deformations? How do energy losses and loading capability change with speed?
Objective SO2
How do macro and micro features influence energy losses and loading capability? How does an optimized design depend on the flow and loading parameters?
Objective SO3
Is the numerical TVEHL theory validated experimentally? How does the new journal bearing perform out of the design conditions and, specifically, in boundary lubrication?