Influencing Factors of the Optimum Offset Ratio of Elastic Cushions of Elastically Supported Tilting Pad Thrust Bearings

doi:10.3901/JME.2020.01.091

Abstract

Abstract: In order to optimize the offset ratio of the rubber cushion of a rubber-supported water-lubricated tilting pad thrust bearing, and to study the influencing factors of the optimum offset ratio, a thermohydrodynamic lubrication performance calculation model of the bearing is proposed. A finite element method is adopted to calculate the support force and moment of the rubber cushion acting on the thrust pad under non-uniform compression. The relationship equations of the support force and the moment with compression and tilting angles are fitted. A finite difference method is used to solve the governing equations in the fluid domain. The effects of load, rotational speed, dimensions and length to width ratio of a thrust pad on the optimum offset ratios of the rubber cushion are studied. The results show that the optimum offset ratios are independent of load and speed, but affected by the length and width of the thrust pad. When the size and material of the rubber cushion remain unchanged, the radial and circumferential optimum offset ratios of the rubber cushion decrease and increase with the increase of pad length, respectively. The radial and circumferential optimum offset ratios increase and decrease with the increase of pad width. Increase the length and width simultaneously while keeping the length to width ratio constant, the optimum offset ratios in both directions increase. When the offset values of the rubber cushion are chosen from the optimum value ranges, the calculated film thickness ratios in circumferential and radial directions are also in their optimum value ranges, and the optimum value ranges are 1.3-1.4 and 0.12-0.20, respectively. The research methods and results are of guiding significance to the design of elastic rubber cushion supported tilting pad thrust bearings.

Key words: tilting pad thrust bearing, rubber-supported, water-lubricated, optimization

CLC Number:

U664

LIANG Xingxin, YAN Xinping, OUYANG Wu, LIU Zhenglin. Influencing Factors of the Optimum Offset Ratio of Elastic Cushions of Elastically Supported Tilting Pad Thrust Bearings[J]. Journal of Mechanical Engineering, 2020, 56(1): 91-99.

References

[1] 吴铸新,刘正林,王隽,等. 水润滑轴承推力瓦块材料摩擦磨损试验研究[J]. 兵工学报,2011,32(1):118-123. WU Zhuxin,LIU Zhenglin,WANG Jun,et al. Research on friction and wear testing of pad materials of water-lubricated thrust bearings[J]. Acta Armamentarii,2011,32(1):118-123.
[2] YAN X,LIANG X,OUYANG W,et al. A review of progress and applications of ship shaft-less rim-driven thrusters[J]. Ocean Engineering,2017,144:142-156.
[3] SUN Y,YAN X,YUAN C,et al. Insight into tribological problems of green ship and corresponding research progresses[J]. Friction,2018,6(4):472-483.
[4] 宋智翔,刘莹,郭飞,等. 屏蔽式核主泵水润滑可倾瓦推力轴承推力盘的离心效应[J]. 机械工程学报,2018,54(1):127-135. SONG Zhixiang,LIU Ying,GUO Fei,et al. Influence of centrifugal deformation of thrust collar in water-lubricated tilting-pad thrust bearings of nuclear canned pump[J]. Journal of Mechanical Engineering,2018,54(1):127-135.
[5] DONG C,YUAN C,BAI X,et al. Investigating relationship between deformation behaviours and stick-slip phenomena of polymer material[J]. Wear,2017,376:1333-1338.
[6] DONG C,YUAN C,BAI X,et al. Study on wear behaviours for NBR/stainless steel under sand water-lubricated conditions[J]. Wear,2015,332:1012-1020.
[7] 张赣波,赵耀,储炜,等. 船舶可倾瓦推力轴承润滑油膜的轴向动特性计算方法[J]. 船舶力学,2017,21(5):603-612. ZHANG Ganbo,ZHAO Yao,CHU Wei,et al. Calculation method for axial dynamic characteristics of lubricant oil film in marine tilting pad thrust bearing[J]. Journal of Ship Mechanics,2017,21(5):603-612.
[8] 王占朝,刘莹,郭飞,等. 支点变形对水润滑可倾瓦推力轴承起动过程影响[J]. 摩擦学学报,2018,38(2):180-188. WANG Zhanchao,LIU Ying,GUO Fei,et al. Influence of the pivot deformation on the water lubrication tilting-pad thrust bearing during boot process[J]. Tribology,2018,38(2):180-188.
[9] 梁兴鑫,严新平,刘正林,等. 水润滑可倾瓦推力轴承设计与性能分析[J]. 交通运输工程学报,2017,17(4):89-97. LIANG Xingxin,YAN Xinping,LIU Zhenglin,et al. Design and performance analysis of a water lubricated tilting pad thrust bearing[J]. Journal of Traffic and Transportation Engineering,2017,17(4):89-97.
[10] 尤治博,刘德新,耿在明,等. 溪洛渡水电站弹性橡胶垫支撑式推力轴承结构分析[J]. 水力发电,2013,39(8):42-44. YOU Zhibo,LIU Dexin,GENG Zaiming,et al. Structure analysis of thrust bearing with rubber spring plate support in Xiluodu hydropower station[J]. Water Power,2013,39(8):42-44.
[11] PAJACZKOWSKI P. Simulation of transient states in large hydrodynamic thrust bearings[D]. Gdansk:Gdansk University of Technology,2010.
[12] 王焕栋. 关于弹性垫支撑自调节受力推力轴承的研究与应用[J]. 水电站机电技术,2015,38(1):5-9. WANG Huandong. Research and application of self-adjusting forced thrust bearing supported by elastic cushion[J]. Mechanical and Electrical Technique of Hydropower Station,2015,38(1):5-9.
[13] 王守忠. 弹性橡胶垫推力轴承偏心值的选取[J]. 水电站机电技术,1993(3):40-43. WANG Shouzhong. The selection of the eccentricity of the elastic rubber pad supported thrust bearing[J]. Mechanical and Electrical Technique of Hydropower Station,1993(3):40-43.
[14] WANG X,ZHANG Z,ZHANG G. Improving the performance of spring-supported thrust bearing by controlling its deformations[J]. Tribology International,1999,32(12):713-720.
[15] YUAN J,MEDLEY J,FERGUSON J. Spring-supported thrust bearings used in hydroelectric generators:Comparison of experimental data with numerical predictions[J]. ASLE Transactions,2001,44(1):27-34.
[16] LIANG X,YAN X,OUYANG W,et al. Thermo-Elasto-Hydrodynamic analysis and optimization of rubber-supported water-lubricated thrust bearings with polymer coated pads[J]. Tribology International,2019,138:365-379.
[17] 彭旭东,刘伟,白少先,等. 热弹变形对核主泵用流体静压型机械密封性能的影响[J]. 机械工程学报,2010,46(23):146-153. PENG Xudong,LIU Wei,BAI Shaoxian,et al. Effects analysis of thermo-elastic deformation on the performance of hydrostatic mechanical seals in reactor coolant pumps[J]. Journal of Mechanical Engineering,2010,46(23):146-153.
[18] 张直明. 滑动轴承的流体动力润滑理论[M]. 北京:高等教育出版社,1986. ZHANG Zhiming. Hydrodynamic lubrication theory of sliding bearings[M]. Beijing:Higher Education Press,1986.
[19] FOWELL M,MYANT C,SPIKES H,et al. A study of lubricant film thickness in compliant contacts of elastomeric seal materials using a laser induced fluorescence technique[J]. Tribology International,2014,80:76-89.