Investigation of passive bearing for biomedical applications

• Main Author: Lee, Jian Ming.
• Other Authors: Chan Weng Kong
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/53291
• Institution: Nanyang Technological University

Hydrodynamic bearings have been widely used in many industries for a long time. The principles of the hydrodynamic bearing are that fluid is pumped into the inner surface of the bearing, forming a lubricating wedge around or under the shaft. Its simplicity and low cost of production and low maintenance makes it popular with design engineers. In modern technology today, hydrodynamic bearings are currently used in the biomedical and bioengineering industries. In this project, theoretical equations used by many researchers are being investigated and analyzed. The theory behind the spiral groove bearing or SGB is explained and the formula is investigated numerically. Derivations of pressure rise across the SGB were presented and the result graph plotted. Parameters such as the spiral angle, film height to groove height ratio, ridge width to groove width ratio, inner radius to outer radius ratio and the number of grooves were analyzed. Using the results obtained from the different variations, the effects were analyzed and optimum values for the pressure across the SGB were obtained. Results taken from the theoretical modeling by varying parameters such as film height and grooves, coupled with the results from past CFD simulations concluded that the equations had difference in the pressure rise across the SGB due to inertia effects that were not accounted for in the theoretical formulation. Another reason for the difference in theoretical and CFD results was that the pressure varies linearly at the entrance of the groove and ridge might not be accurate.