Abstract
Aerostatic lubrication can be used in precision and high-speed applications. Aerostatic porous bearings and seals form a lubricating gas film between two surfaces by supplying pressurized gas to the gap through a permeable surface. Externally pressurized porous bearings can be used for simultaneous sealing and bearing functions. The aim of this research is to theoretically and experimentally investigate the performance of aerostatic bearings and seals and to improve modeling of flow in porous externally pressurized bearings and seals. Developed bearing and seal models use the modified Reynolds equation that includes a porous feeding term. The proposed analytical and numerical solutions are verified with multiple experiments under static conditions. Experimental setup and measurement methods of bearing and seal performance parameters are developed. Outer diameter of the experimentally investigated bearings and seals are in the range of 40 mm to 62 mm. It is shown that the analytic solution is equivalent to numerical solutions of the Reynolds equation on the most significant performance metrics under static conditions. Investigated performance characterizing metrics of aerostatic bearings and seals include load capacity, air gap height, stiffness, air consumption, and leakage. Further, effect of design and operational parameters on the performance are investigated. The investigated design parameters include the permeability of the porous restrictor and the seal width, while investigated operational parameters include the supply and chamber pressures and preload of the seal. Some of the results are presented in nondimensional form for better applicability to general problems. Finally, a robust aerostatic bearing concept tolerant of large movements of the guide surface is developed and its performance is investigated under realistic dynamic conditions for paper machine applications. The developed bearing concept achieved a load capacity of 18.5 kN. These results give corroborative evidence on feasibility of the proposed bearing for use in paper machinery. The results of this research are relevant for design of aerostatic bearings and seals and applications where good motion accuracy or low friction motion are required.
Translated title of the contribution | Huokoiset aerostaattiset tiivisteet ja laakerit suurille roottoreille |
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Original language | English |
Qualification | Doctor's degree |
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Publisher | |
Print ISBNs | 978-952-64-2129-2 |
Electronic ISBNs | 978-952-64-2130-8 |
Publication status | Published - 2024 |
MoE publication type | G5 Doctoral dissertation (article) |
Keywords
- gas lubrication
- externally pressurised seal