Simulation of gas bearings in carbon dioxide linear compressors

doi:10.11949/0438-1157.20241171

Abstract

Abstract:

Linear compressors offer superior performance with excellent capacity modulation, enhancing system efficiency and enabling adaptation to a wide range of operating conditions. These characteristics make them highly suitable for applications in refrigeration and cryogenic systems. Gas bearing technology facilitates oil-free lubrication and ensures high reliability in linear compressors. Carbon dioxide (CO₂), as an environmentally friendly refrigerant, has a low global warming potential (GWP) and an ozone depletion potential (ODP) of zero, along with excellent thermophysical properties. In this study, a porous gas bearing model is developed using CO₂ as the working fluid. Simulations are performed using Fluent software to evaluate the influence of porous material thickness, gas gap thickness, supply pressure, and eccentricity on the gas consumption and load capacity of the gas bearing. Using response surface methodology, the optimal design parameters were determined to be a gas gap thickness of 10.0—11.1 μm and a porous material thickness of 2.11—3.50 mm. These results provide a valuable reference for the design of gas bearings in CO₂ linear compressors.

Key words: carbon dioxide, compressor, gas bearings, optimized design

摘要：

直线压缩机性能优越，具有良好的容量调节能力，能够提升系统效率、适应多样化运行工况，在制冷、低温领域具有广泛的应用前景。气体轴承技术可实现直线压缩机的无油润滑和高可靠性。二氧化碳是一种环保制冷剂，低GWP、OGP为0且具有良好的性能。以二氧化碳为制冷剂，建立多孔质气体轴承模型，利用Fluent软件进行模拟计算，对多孔质材料厚度、气隙厚度、供气压力、偏心率对气体轴承耗气量和承载力的影响进行仿真分析，通过响应曲面法确定了最佳设计参数组合为气隙厚度10.0~11.1 μm、多孔质材料厚度为2.11~3.50 mm，为二氧化碳直线压缩机气体轴承的设计提供参考。

关键词: 二氧化碳, 压缩机, 气体轴承, 优化设计

CLC Number:

TB 652

Fanchen KONG, Shuo ZHANG, Mingsheng TANG, Huiming ZOU, Zhouhang HU, Changqing TIAN. Simulation of gas bearings in carbon dioxide linear compressors[J]. CIESC Journal, 2025, 76(S1): 281-288.

孔繁臣, 张硕, 唐明生, 邹慧明, 胡舟航, 田长青. 二氧化碳直线压缩机气体轴承模拟[J]. 化工学报, 2025, 76(S1): 281-288.

Figures/Tables 15

Fig.1 Porous gas bearing structure for linear compressor

Fig.2 Porous gas bearing cross-section structure and eccentricity

Fig.3 Porous gas bearing model

Table 1 Piston cylinder structure

参数	数值
活塞直径D/mm	16
气缸长度L/mm	30
多孔质材料厚度/mm	3
气隙厚度/μm	12
工质	CO₂

Fig.4 Porous gas bearing mesh generation

Table 2 Grid independence check

网格划分（r，θ，z）	网格数量/个	耗气量/(10^-4 kg/s)	耗气量误差/%
10，120，120	144000	1.559	0.369
15，120，120	216000	1.555	0.128
20，120，120	288000	1.553	—
25，120，120	360000	1.552	-0.061
30，120，120	432000	1.552	-0.075

Fig.5 Gap pressure distribution cloud diagram of gas bearing

Fig.6 Experimental test equipment

Table 3 Porous piston cylinder test conditions

测试样品

测试条件

二氧化碳直线压缩机

多孔质气缸活塞组合件

供气压力1.5, 2.0, 2.5, 3.0, 3.5 MPa

Fig.7 Comparison of simulation results with experimental results

Fig.8 Effect of eccentricity on gas bearings

Fig.9 Effect of air gap thickness on gas bearings

Fig.10 Effect of porous material thickness on gas bearings

Fig.11 Effect of air gap thickness and porous material thickness on bearing capacity

Fig.12 Effect of air gap thickness and porous material on gas consumption

References 30

12	邹慧明, 王英琳, 唐明生, 等. 直线压缩机用多孔质气体轴承的仿真与实验[J]. 制冷学报, 2021, 42(4): 122-129, 141.
	Zou H M, Wang Y L, Tang M S, et al. Simulation and experimental investigation on porous gas bearings for linear compressor[J]. Journal of Refrigeration, 2021, 42(4): 122-129, 141.
13	王林, 江荣鼎, 张春晓, 等. 含R1234yf混合工质汽液相平衡的混合规则评估与预测研究[J]. 化工学报, 2024, 75(2): 475-483.
	Wang L, Jiang R D, Zhang C X, et al. Evaluation and predictive study of the mixing rules for vapor-liquid equilibrium of R1234yf mixtures[J]. CIESC Journal, 2024, 75(2): 475-483.
14	董益秀, 王如竹. 高温热泵的循环、工质研究及应用展望[J]. 化工学报, 2023, 74(1): 133-144.
	Dong Y X, Wang R Z. High temperature heat pump: cycle configurations, working fluids and application potentials[J]. CIESC Journal, 2023, 74(1): 133-144.
15	安青松, 侯佳鑫, 史琳, 等. 欧盟PFAS限制提案解读及其对制冷空调行业影响与应对[J]. 制冷学报, 2024, 45(2): 22-29.
	An Q S, Hou J X, Shi L, et al. Interpretation of the EU PFAS restriction proposal and its impact on R&AC industry[J]. Journal of Refrigeration, 2024, 45(2): 22-29.
16	Ma Y T, Liu Z Y, Tian H. A review of transcritical carbon dioxide heat pump and refrigeration cycles[J]. Energy, 2013, 55: 156-172.
17	Tang Z H, Zhang S, Zou H M, et al. Operational stability influenced by lubricant oil charge in the CO₂ automotive air conditioning system[J]. International Journal of Refrigeration, 2024, 158: 58-67.
18	袁昊瑞, 宋霞, 俞彬彬, 等. 带余热回收的CO₂车用热泵系统实验研究[J]. 制冷学报, 2023, 44(2): 54-60.
	Yuan H R, Song X, Yu B B, et al. Experimental research on the heating performance of waste heat recovery CO₂ heat pumps for electric vehicles[J]. Journal of Refrigeration, 2023, 44(2): 54-60.
19	Dilshad S, Kalair A R, Khan N. Review of carbon dioxide (CO₂) based heating and cooling technologies: past, present, and future outlook[J]. International Journal of Energy Research, 2020, 44(3): 1408-1463.
20	Wang L, Linghu H F, Huang C J, et al. Performance investigation of a supergravity CO₂ refrigeration cycle under off-design conditions[J]. Applied Thermal Engineering, 2024, 254: 123841.
21	Fomin Y D, Ryzhov V N, Tsiok E N, et al. Thermodynamic properties of supercritical carbon dioxide: widom and Frenkel lines[J]. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics, 2015, 91(2): 022111.
22	朱芝, 许恒杰, 陈维, 等. 超临界二氧化碳螺旋槽干气密封热流耦合润滑临界阻塞特性研究[J]. 化工学报, 2024, 75(2): 604-615.
	Zhu Z, Xu H J, Chen W, et al. Study on critical chocked characteristics of supercritical carbon dioxide spiral groove dry gas seal under thermal-fluid coupling lubrication[J]. CIESC Journal, 2024, 75(2): 604-615.
23	李海宁, 张晓青, 李奎, 等. 动磁直线压缩机气体轴承特性的CFD模拟[J]. 工程热物理学报, 2013, 34(6): 1026-1030.
	Li H N, Zhang X Q, Li K, et al. CFD simulation of gas bearing characteristic for a moving-magnet linear compressor[J]. Journal of Engineering Thermophysics, 2013, 34(6): 1026-1030.
24	洪昊, 赵志康, 陈曦, 等. 小型对置式直线压缩机模拟及实验研究[J]. 能源研究与信息, 2021, 37(4): 187-192, 206.
	Hong H, Zhao Z K, Chen X, et al. Simulation and experimental research on small opposed linear compressor[J]. Energy Research and Information, 2021, 37(4): 187-192, 206.
25	李诚展, 李建国, 孙建, 等. 无油线性压缩机的频率特性和活塞偏移特性研究[J]. 振动与冲击, 2021, 40(3): 139-146.
	Li C Z, Li J G, Sun J, et al. Frequency characteristics and piston offset characteristics of oil-free linear compressor[J]. Journal of Vibration and Shock, 2021, 40(3): 139-146.
26	杨明卓, 焦珂欣, 池春云, 等. 间隙密封高频往复运动活塞偏移特性研究[J]. 润滑与密封, 2024, 49(4): 81-86.
	Yang M Z, Jiao K X, Chi C Y, et al. Study on the high frequency reciprocating piston offset character under clearance seal[J]. Lubrication Engineering, 2024, 49(4): 81-86.
1	Liang K. A review of linear compressors for refrigeration[J]. International Journal of Refrigeration, 2017, 84: 253-273.
2	邹慧明, 王英琳, 李旋, 等. R290直线压缩机变工况制冷性能[J]. 化工学报, 2021, 72(S1): 342-347.
	Zou H M, Wang Y L, Li X, et al. R290 linear compressor under variable conditions[J]. CIESC Journal, 2021, 72(S1): 342-347.
3	邹慧明, 李旋, 唐明生, 等. R290工质直线压缩机的性能实验研究[J]. 化工学报, 2018, 69(S2): 480-484.
	Zou H M, Li X, Tang M S, et al. Experimental investigation on refrigeration performance of R290 linear compressor[J]. CIESC Journal, 2018, 69(S2): 480-484.
4	Kong F C, Tang M S, Zou H M, et al. Performance simulation analysis of a novel dual-piston two-stage carbon dioxide linear compressor[J]. International Journal of Refrigeration, 2024, 159: 185-194.
5	Li C Z, Zou H M, Cai J H, et al. Dynamic behavior analysis of a moving coil oil-free linear compressor in refrigeration system[J]. International Journal of Refrigeration, 2022, 133: 235-246.
6	王天娜, 矫佳伟, 丁奕涵, 等. 气悬浮制冷压缩机的研究进展[J]. 制冷, 2024, 43(2): 90-94.
	Wang T N, Jiao J W, Ding Y H, et al. Research progress of air suspension refrigeration compressors[J]. Refrigeration, 2024, 43(2): 90-94.
7	滕斌, 杨启超, 王春, 等. 以制冷剂为工作介质的止推气体轴承静态特性分析[J]. 润滑与密封, 2021, 46(8): 54-61.
	Teng B, Yang Q C, Wang C, et al. Analysis of static characteristics of thrust air bearing of centrifugal refrigeration compressor[J]. Lubrication Engineering, 2021, 46(8): 54-61.
8	王青锋, 祁影霞, 潘帅, 等. 线性压缩机气体轴承数值模拟研究[J]. 制冷技术, 2019, 39(2): 29-33.
	Wang Q F, Qi Y X, Pan S, et al. Numerical simulation of gas bearing for linear compressor[J]. Chinese Journal of Refrigeration Technology, 2019, 39(2): 29-33.
9	梁天晓, 陈曦, 洪昊, 等. 小型线性压缩机静压气体轴承的模拟分析[J]. 真空与低温, 2021, 27(3): 262-266.
	Liang T X, Chen X, Hong H, et al. Simulation analysis of hydrostatic gas bearing of small linear compressor[J]. Vacuum and Cryogenics, 2021, 27(3): 262-266.
10	王春, 赵远扬, 衣可心, 等. R134a静压气体轴承静特性及其对制冷系统的影响研究[J]. 机床与液压, 2022, 50(15): 92-96.
	Wang C, Zhao Y Y, Yi K X, et al. Gas bearing static pressure characteristics of refrigeration centrifugal compressor with R134a and its influence on refrigeration system[J]. Machine Tool & Hydraulics, 2022, 50(15): 92-96.
11	Li J G, Wu J J, Fan J D, et al. Research on dynamic characteristics and structural optimization of porous gas bearings in linear compressors[J]. Scientific Reports, 2023, 13(1): 16507.
27	邹慧明, 汤鑫斌, 唐明生, 等. CO₂直线压缩机设计与变工况性能分析[J]. 压缩机技术, 2021(2): 9-17.
	Zou H M, Tang X B, Tang M S, et al. Design of CO₂ linear compressor and performance analysis with variable working conditions[J]. Compressor Technology, 2021(2): 9-17.
28	Koohestanian E, Samimi A, Mohebbi-Kalhori D, et al. Sensitivity analysis and multi-objective optimization of CO₂ CPU process using response surface methodology[J]. Energy, 2017, 122: 570-578.
29	Reihani A, Hoard J, Klinkert S, et al. Experimental response surface study of the effects of low-pressure exhaust gas recirculation mixing on turbocharger compressor performance[J]. Applied Energy, 2020, 261: 114349.
30	Redhwan A A M, Azmi W H, Najafi G, et al. Application of response surface methodology in optimization of automotive air-conditioning performance operating with SiO₂/PAG nanolubricant[J]. Journal of Thermal Analysis and Calorimetry, 2019, 135(2): 1269-1283.

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