Viscosity Effect on Stiffness of Non-conventional (Five Tilted Pads) Journal Bearing
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Abstract
In this tribological study, we highlight the effect of lubricating oil viscosity in the Multi-pads hydrodynamic journal bearings generate important improvement in characteristics of stiffness and stability in the high speed turbomachines. Depending on viscosity of oil film (three values) variation for five tilted pads bearing, each pad is pivoted and is facilitated to be tilted with small angles, by using Matlab program, we calculate the oil film thickness for convergence layer. We applied Reynold's equation and solved it's numerically by using finite difference method with 5 nodes technique to find the pressure distributed on each node in the mesh of tilted pad, then calculate stiffness coefficients. Results show that there is clear effect on stiffens with viscosity change. The increase in value of Krr (for n = 0.3) between viscosity (0.04 Pas. s) and viscosity (0.058 Pas. s) is14.33 MN/m, while the increase in Krr value between viscosity (0.058 Pas. s) and viscosity (0.087 Pas. s) is 11.37 MN/m. the increase in value the of Kss (for n = 0.3) between viscosity (0.04 Pas. s) and viscosity (0.058 Pas. s) is5.921 MN/m, while increase in Kss value between viscosity (0.058 Pas. s) and viscosity (0.087 Pas. s) is9.55 MN/m respectively. the increase in value of Ksr (for n = 0.3) between viscosity (0.04 Pas. s) and viscosity (0.058 Pas. s) is 8.95 MN/m, while the increase in Ksr value between viscosity (0.058 Pas. s) and viscosity (0.087 Pas. s) is 14.41 MN/m respectively. the increase in value of Krs (for n = 0.3) between viscosity (0.04 Pas. s) and viscosity (0.058 Pas. s) are 5.08 MN/m, while the increase in Krs value between viscosity (0.058 Pas. s) and viscosity (0.087 Pas. s) is8.19 MN/m respectively. The values of the dominate principal coefficients Krr is greater than that of Ksr, also The values of the principal coefficients Kss is greater than that of cross coupling Krs for all values of viscosity that studied. From this result, we can conclude the side effect of cross coupling coefficients (Ksr ,Krs) can be overcome by great values for principal coefficient (Krr, Kss) respectively, so we can get good improvement instability for this bearing by variation the viscosity. After that, we regarded to use high viscosity lubricant in multi-pad journal bearing to improve the performance and stability by controlling the stiffness coefficients.
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References
Armentrout RW, Paquette DJ. Rotordynamic characteristics
of flexure-pivot tilting-pad journal bearings. STLE
Tribology Transactions 1993; 36 (3): 443-451. DOI: https://doi.org/10.1080/10402009308983182
Glienike J, Han DC, Leonhard M. Practical determination
and use of bearing dynamic coefficients. Tribology
International 1980; 13 (6): 297-309. DOI: https://doi.org/10.1016/0301-679X(80)90094-8
Zhi LQ. A theoretical and experimental study on dynamic
characteristics of journal bearing. Ph.D. Thesis:
Wollongong University: 1995.
Lund JW, Thomsen KK. A calculation method and data for
the dynamic coefficients of oil-lubricated journal bearings.
Topics in Fluid Film Bearing and Rotor Bearing System
Design and Optimization ASME 1978: 1-28.
Malik M, Chandara M, Sinhasan R. Performance
characteristic of tilted three lobe journal bearing
configuration. India Journal of Tribology International
: 345-349.
Marco TCF. Finite element analysis of oil-lubricated
elliptical journal bearings. International Journal of
Mechanical, Aerospace, Industrial, Mechatronic and
Manufacturing Engineering 2015; 9 (5): 705-710. DOI: https://doi.org/10.17973/MMSJ.2015_10_201540
Nicholas JC, Gunter EJ, Allaire PE. Stiffness and damping
coefficients for the five-pad tilting-pad bearing. American
Society of Lubrication Conference (ASLA), 1977: pp. 1-9.
Huang TW, Weng CI. Dynamic characteristics of finitewidth
journal bearings with micropolar fluids. Wear 1990;
(1): 23-33.
Standard GTW Tilting Pad Journal Bearings type W140
with 4-pads and W141 with 5-pads. Tilting pad journal
bearings catalogue. Types W140 and W141diameter range
…355 mm, www.gtw.cz.
Dowson D. Hydrodynamic bearings. 1st ed.UK: Tribology series; 1989.
Andres LS. Dynamics of a rigid rotor fluid film bearing system. Texas A&M University, College station; Lecture: pp 117-136. 2010.
Crosby WA, Chetti B. The static and dynamic characteristics of a two-lobe journal bearing lubricated with couple-stress fluid. Tribology Transactions 2009; 52: 262-268. DOI: https://doi.org/10.1080/10402000802527773
Jain S, Bajpai L. Analysis of fluid film stiffness and damping coefficient for a circular journal bearing with
micropolar fluid. International Journal on Emerging Technologies 2014; 5 (1): 206-211.
Kuznetsov E, Glavatskih S. Stability analysis of a compliant lemon bore journal bearing. Proceedings of the 9th Biennial ASME Conference on Engineering Systems Design and Analysis 2008 7-9 July. DOI: https://doi.org/10.1115/ESDA2008-59589
Khelifa MZ. The dynamic coefficients and elastic deformation with thermal effect for cylindrical pivot tilting 5-pad bearing. Engineering and Technology Journal 2009 27 (15): 2760-2774