Analysis of Non-Contacting Air Bearing Under Ultra Thin Lubrication Condition

• Main Authors: Chih-Cheng Yu, 余志成
• Other Authors: Shun-Ching Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/75169695148151045770

碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 93 === The thickness of noncontacting gas lubricated face seals about . So small film thickness, the behavior of the lubricant may be not continuity. Such the consideration of rarefaction gas effects is necessary. In addition, small film thickness request and stability, make roughness caused influence must the discussion extremely. In this thesis, the finite element methods are used for the dynamic analysis of noncontacting gas lubricated face seals. This method enabling the solution for any faces geometry of spiral-grooved gas seals. Reynolds equation is two-dimensionally nonlinear ordinary differential equation. Self-adapting unwinding schemes are employed in finite element methods, making suitable for situations when the compressibility number is high. First, we because of Navier-Stokes Equation theory to derivation compress Reynolds equation. According to the rarefaction gas effect, interact of air molecular to discuss with accommodation coefficients. The theory of molecule’s gas lubrication generally and different Knudsen Number are used to simulate the surface property of face seal. We hope to predict the mode of divination dilute gas flow when the face seals processing by simulation. In the second part, applied average flow rate into the generalized Reynolds equation. Using the perturbation approach and coordinate transformation, the flow factors are derived. The relations expressing the effects of roughness orientations and molecular mean free path on the roughness-induced flow factors are derived. The generalized Reynolds equation is linearism by perturbation technique due to small variation of film thickness. The air film is modeled as dynamic coefficient, and then the influences of oscillation frequency, bearing number, roughness parameters, and inverse Knudsen number on the thinning lubricant on the gas seals.