Sage Journals: Discover world-class research

Abstract

The variable-speed scroll compressors can adapt to the various demands of heating and cooling capacity, and the rotational speeds significantly influence the rotor dynamic and bearings lubrication, which might cause performance and reliability issues. In this paper, numerical models for the rotor-bearing-frame system are developed by coupling the Reynolds equation, rotor dynamic equation, and the flexibility equation of the frame. The experimental apparatus is also established to directly measure the journal displacement response in the hermetic high-pressure shell of the compressor. The predicted journal center trajectories are compared with the experimental results and they show good agreement. Results show that the whirl radius decreases with the increase of rotational speed at the measuring point, while the opposite tendency can be observed at the bottom of the main bearing. Transient dynamic analysis of the rotor shows that the tilting and deformation of the rotor vary with respect to different rotational speeds. The displacement of the crank part could lead to the separating tendency between orbiting and fixed scrolls through the coupled orbiting bearing, especially at the lower rotational speed, due to the pull of main balance weight. The numerical results also reveal that the distribution of oil film pressure is dominated by the squeeze effect due to the relatively stable magnitude but the variable direction of loads on the shaft. The influence of the deformation of the cantilevered bearing frame on the oil film thickness is significant but the maximum deformation moves downward at the higher rotational speed.

Keywords

Scroll compressor dynamic lubrication experiment simulation

Get full access to this article

View all access options for this article.

References

Sève

Andrianoely

Berlioz

, et al. Balancing of machinery with a flexible variable-speed rotor. J Sound Vib 2003; 264: 287–302.

Chang

Park

Choi

, et al. Reliability evaluation of scroll compressor for system air conditioner. J Mech Sci Technol 2016; 30: 4459–4463.

Wang

Liu

, et al. Dynamic analyses for the rotor-journal bearing system of a variable speed rotary compressor. Int J Refrig 2013; 36: 1938–1950.

Rao

. History of Rotating Machinery Dynamics. Dordrecht: Springer Netherlands, 2011. https://doi.org/10.1007/978-94-007-1165-5.

Bush

Elson

. Scroll compressor design criteria for residential air conditioning and heat pump applications. Part I: mechanics. Int Compress Eng Conf Sch 1988: 605.

Narumiya

. Journal bearing performance in a scroll compressor. Int Compress Eng Conf Sch 1992: 881.

Bryant

. Reynolds equation for compressible fluid or gas film. In: Encycl. Tribol. Boston, MA: Springer US, 2013, pp. 2773–2775. https://doi.org/10.1007/978-0-387-92897-5_223.

Silva

HAP

Nicoletti

. Rotor vibration control using tilting-pad journal bearing with active pads — Numerical and experimental results. J Sound Vib 2023; 546: 117441.

Ahn

Choi

Rhim

. Analysis of journal bearings in a scroll compressor considering deflections and dynamics of the crankshaft. Int J Refrig 2018; 93: 205–212.

10.

Kim

Hong

Jang

. Dynamic analysis of a flexible shaft in a scroll compressor considering solid contact and oil film pressure in journal bearings. Int J Refrig 2021; 127: 165–173.

11.

Okaichi

Hasegawa

Nishiwaki

. A study on lubrication characteristics of journal and thrust bearings in scroll compressors. Int Compress Eng Conf 2004: 1686.

12.

Oyamada

. Application of ultrasonic sensing to monitoring lubrication conditions in a refrigeration compressor. Tribol Trans 2017; 60: 763–769.

13.

Fukuta

Yanagisawa

Shimasaki

, et al. Real-time measurement of mixing ratio of refrigerant/refrigeration oil mixture. Int J Refrig 2006; 29: 1058–1065.

14.

Prata

Barbosa

Jr . The thermodynamics, heat transfer and fluid mechanics role of lubricant oil in hrmetic reciprocating compressors. Fluid Mech. Thermodyn 2007.

15.

Kasolang

Dwyer-Joyce

. Observations of film thickness profile and cavitation around a journal bearing circumference. Tribol Trans 2008; 51: 231–245.

16.

Sang-Shin

Gyu-Ha

Jin-Kab

. Analyses and measurements of rotational accuracy for journal shaft in a scroll compressor. Korean Soc Tribol Lubr Eng 2007; 23: 83–88.

17.

Wang

Cheng

, et al. Elasto-hydrodynamic lubrication of the journal bearing system with a relief groove in the scroll compressor: simulation and experiment. Tribol Int 2022; 165: 107252.

18.

Nelson

. A finite rotating shaft element using timoshenko beam theory. J Mech Des 1980; 102: 793–803.

19.

Wang

Zhang

Lei

, et al. Analysis on influence factors of back pressure in an asymmetrical algebraic scroll compressor. Int J Refrig 2022; 138: 97–107.

20.

Patir

Cheng

. Application of average flow model to lubrication between rough sliding surfaces. J Lubr Technol 1979; 101: 220–229.

21.

Jang

Yoon

. Nonlinear dynamic analysis of a hydrodynamic journal bearing considering the effect of a rotating or stationary herringbone groove. J Tribol 2002; 124: 297–304.

22.

Greenwood

. The contact of two nominally flat rough surfaces. Proc Inst Mech Eng 1971; 185: 625–633.

23.

Xiang

Han

Wang

, et al. Coupling transient mixed lubrication and wear for journal bearing modeling. Tribol Int 2019; 138: 1–15.

24.

Tojo

. Evolution and future prospects of scroll compressor technology. Trans Japan Soc Refrig Air Cond Eng 2020; 37: 123–144.

25.

Liu

Han

, et al. Identification of oil-film coefficients for a rotor-journal bearing system based on equivalent load reconstruction. Tribol Int 2016; 104: 285–293.

26.

Bathe

K.-J

. Finite element procedures, 2006.

27.

Liu

Ellison

, et al. Application of computational fluid dynamics and fluid-structure interaction method to the lubrication study of a rotor-bearing system. Tribol Lett 2010; 38: 325–336.

28.

Dhande

Pande

. A two-way FSI analysis of multiphase flow in hydrodynamic journal bearing with cavitation. J Brazilian Soc Mech Sci Eng 2017; 39: 3399–3412.

29.

Morris

Shahmohamadi

Rahmani

, et al. Combined experimental and multiphase computational fluid dynamics analysis of surface textured journal bearings in mixed regime of lubrication. Lubr Sci 2018; 30: 161–173.

30.

Chen

Lin

, et al. Experimental analysis on R290 solubility and R290/oil mixture viscosity in oil sump of the rotary compressor. Int J Refrig 2018; 94: 24–32.

31.

Meng

. Numerical analyses of hydrodynamic lubrication and dynamics of the rolling piston and crankshaft in a rotary compressor. Tribol Trans 2014; 57: 1136–1147.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.80 MB

Experimental and numerical study on the dynamic and lubrication characteristics of the rotor-bearing-frame system in a variable-speed scroll compressor

Abstract

Keywords

Get full access to this article

References

Supplementary Material