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20 pages, 6428 KiB

Open AccessArticle

Dynamic Models of Mechanical Seals for Turbomachinery Application

by Renat Badykov, Sergei Falaleev, Maxim Benedyuk and Dmitriy Diligenskiy

Lubricants 2024, 12(10), 355; https://doi.org/10.3390/lubricants12100355 - 16 Oct 2024

Viewed by 870

Abstract

One of the primary causes of mechanical face seal failure is rotor vibration. Traditional dynamic seal models often cannot fully explain failure mechanisms. The dynamic models of seals proposed in this paper, including those developed by the authors, are valuable for predicting seal [...] Read more.

One of the primary causes of mechanical face seal failure is rotor vibration. Traditional dynamic seal models often cannot fully explain failure mechanisms. The dynamic models of seals proposed in this paper, including those developed by the authors, are valuable for predicting seal dynamics during operation in specific turbomachinery and for explaining the causes of seal failure. The single-mass dynamic model is suitable for analyzing the dynamics of contact mechanical face seals and simply designed dry gas seals. The two-mass dynamic model is used to investigate the operational dynamics processes of classical dry gas seals under complex loading conditions. The three-mass dynamic model is used to study various complex types of mechanical face seals. This model can determine the normal operating condition range and explain leakage mechanisms in the presence of excessive rotor vibrations. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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23 pages, 6785 KiB

Open AccessArticle

Influence of Natural Gas Composition and Operating Conditions on the Steady-State Performance of Dry Gas Seals for Pipeline Compressors

by Fan Wu, Jinbo Jiang, Xudong Peng, Liming Teng, Xiangkai Meng and Jiyun Li

Lubricants 2024, 12(6), 217; https://doi.org/10.3390/lubricants12060217 - 14 Jun 2024

Cited by 1 | Viewed by 950

Abstract

A dry gas seal (DGS) is one of the key basic components of natural gas transmission pipeline compressors, and the sealing performance of a DGS dealing with complex multi-component pipeline natural gas is different from that dealing with conventional nitrogen medium. In this [...] Read more.

A dry gas seal (DGS) is one of the key basic components of natural gas transmission pipeline compressors, and the sealing performance of a DGS dealing with complex multi-component pipeline natural gas is different from that dealing with conventional nitrogen medium. In this paper, a spiral groove DGS of the compressor in natural gas transmission pipeline systems is taken as the research object. The thermal hydrodynamic lubrication model of the DGS is established considering turbulence effect and choking effect. Based on the finite difference method, the temperature and pressure distributions and the steady-state performance of the DGS are obtained by simulating. The influence of unitary impurity compositions such as light hydrocarbon, heavy hydrocarbon, non-hydrocarbon, and their contents on the steady-state performance of the DGS is analyzed. The steady-state performance of the DGS dealing with multi-impurity natural gas such as in the West-East gas transmission is investigated under different operating conditions. The results show that turbulence had a significant effect on the DGS, while choking had a weak effect. Increasing the content of light hydrocarbon such as C₂H₆ and heavy hydrocarbon such as C₅H₁₀ resulted in an increase in the gas film stiffness, leakage rate, and the temperature difference between the inlet and outlet, while non-hydrocarbon, such as N₂, reduced the temperature difference between the inlet and outlet. The greatest impact on seal performance was produced by the heavy hydrocarbon, followed by the light hydrocarbon, and the least was produced by the non-hydrocarbon. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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17 pages, 6758 KiB

Open AccessArticle

Experimental Research on Dynamic Characteristics of a Multi-Disc Rotor System Supported by Aerostatic Bearings

by Zhimin Su, Jianbo Zhang, Yimou Cai and Dongjiang Han

Lubricants 2024, 12(5), 151; https://doi.org/10.3390/lubricants12050151 - 27 Apr 2024

Viewed by 968

Abstract

Gas bearings have the advantages of small friction loss, wide applicable speed range, no pollution, etc., and have important application prospects in micro and small high-speed rotating machinery. However, due to its compressibility and low viscosity, its dynamic stability in high-speed rotating machinery [...] Read more.

Gas bearings have the advantages of small friction loss, wide applicable speed range, no pollution, etc., and have important application prospects in micro and small high-speed rotating machinery. However, due to its compressibility and low viscosity, its dynamic stability in high-speed rotating machinery is the key to constraining its development. The experimental study of shaft system dynamics is the main means to explore the mechanism of rotor behavior. On the test platform of dynamic characteristics of multi-disc rotor system supported by aerostatic bearings, experimental research on the nonlinear dynamic characteristics of a rotor system was carried out, and nonlinear vibration test and analysis methods, such as axial orbits, bifurcation diagrams, and spectral characteristics, were adopted, and vibration phenomena, including the critical rotational speed accumulating energy and low-frequency accumulating energy, were presented and the vibration characteristics of bearing fracture faults were presented. The bearing supply pressure and rubber damping pad were introduced as a method to suppress the low-frequency vibration of the aerostatic bearing rotor system, and its vibration-reduction effect was verified by experiments. The above results can provide technical support for vibration control and fault diagnosis of rotor systems supported by aerostatic bearings. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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17 pages, 9683 KiB

Open AccessArticle

Fault Diagnosis of Dry Gas Seal Operation Status Based on Acoustic Emission Monitoring

by Junhua Ding, Shurong Yu, Zhu Liu, Shipeng Wang and Junjie Lu

Lubricants 2024, 12(2), 35; https://doi.org/10.3390/lubricants12020035 - 26 Jan 2024

Cited by 3 | Viewed by 1788

Abstract

A dedicated test bench is employed to record acoustic emission signals from dry gas seals under various operating conditions. Time-domain and frequency-domain analysis methods are utilized to process and analyze the acoustic emission signals during start/stop, stable operation, and two common fault states [...] Read more.

A dedicated test bench is employed to record acoustic emission signals from dry gas seals under various operating conditions. Time-domain and frequency-domain analysis methods are utilized to process and analyze the acoustic emission signals during start/stop, stable operation, and two common fault states (end-face defects and compensation spring failure). Furthermore, feature recognition research is conducted. A method for identifying the operational states of seals (low-speed friction, gradual detachment, stable operation) based on the root mean square (RMS) was established, with transition points at speeds of 100 and 1000 RPM, respectively. Additionally, spectral analysis is conducted using Fourier transform to determine the frequency band of acoustic emission signals (240–320 kHz) generated during contact wear of dry gas seals. Investigation into two typical faults of dry gas seals reveals that the RMS value of the acoustic emission signal gradually increases with the rotational speed during the operation of dry gas seal end-face defects. This is attributed to the insufficient dynamic pressure effect on the end face, resulting in long-term wear and tear. When the dry gas seal compensates for spring failure, the RMS value of the acoustic emission signal initially increases, then decreases, and finally increases again as the speed increases. It reaches the stable operating inflection point when the end-face speed is 800 r/min. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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17 pages, 9932 KiB

Open AccessArticle

Thermal Characteristics of Dry Gas Seal in Startup Process Considering Microscale Effects

by Qiangguo Deng, Xuejian Sun, Hengjie Xu and Wenyuan Mao

Lubricants 2023, 11(12), 503; https://doi.org/10.3390/lubricants11120503 - 29 Nov 2023

Cited by 2 | Viewed by 1788

Abstract

The heat generated during the startup process of dry gas seals, such as the friction heat of the asperities, viscous shear heat, and the expansion heat of the gas film, easily leads to seal failure and endangers the stable operation of turbomachinery. This [...] Read more.

The heat generated during the startup process of dry gas seals, such as the friction heat of the asperities, viscous shear heat, and the expansion heat of the gas film, easily leads to seal failure and endangers the stable operation of turbomachinery. This study combines the statistically modified contact model and the average Reynolds equation by considering the adiabatic index and the microscale effects of dry gas seals to explore the heat generation characteristics of dry gas seals formed in series at multiple times. In particular, the change laws and influencing factors among the components, including the friction heat of asperities and the shear heat and expansion heat of the gas film and total heat, are investigated. A comparative analysis indicates that the slip flow effect increases the total heat during the startup process. The friction heat is much greater than expansion heat and shear heat. Despite constant acceleration, exponential acceleration, or Harrison acceleration, the heat changes are uneven during the startup process. In particular, the heat changes sharply in the early stage and slowly in the later stage. The Harrison acceleration mode is the most conducive to sealing stability. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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21 pages, 10275 KiB

Open AccessArticle

Influence of Cavitation on the Heat Transfer of High-Speed Mechanical Seal with Textured Side Wall

by Minfeng Yu, Xudong Peng, Xiangkai Meng, Jinbo Jiang and Yi Ma

Lubricants 2023, 11(9), 378; https://doi.org/10.3390/lubricants11090378 - 6 Sep 2023

Cited by 2 | Viewed by 1276

Abstract

By setting textures on the side walls of a rotor, based on SST k-ω turbulence and the mixture model, the effects of depth-to-diameter ratio, shape, and rotational speed on interface temperature are analyzed. Local Nu number, flow field in textures, and [...] Read more.

By setting textures on the side walls of a rotor, based on SST k-ω turbulence and the mixture model, the effects of depth-to-diameter ratio, shape, and rotational speed on interface temperature are analyzed. Local Nu number, flow field in textures, and gas distribution are used to verify the conclusion. When rotational speed increases, there are three different stages on the surface: liquid-dominated, mixed two-phase, and gas-dominated. This leads to a big difference in heat transfer on the side wall and causes the temperature on the seal face to increase when cavitation is considered. The distribution of the gas phase is explained through drag reduction, which has a high correlation with the velocity gradient near the surface. For several common shapes, heat transfer enhancement of textures is compared under high speed. The key influencing factor is the depth-to-diameter ratio, which causes flow stratification and reduces heat transfer. Flow stratification leads to different results of maximum temperature on the seal face when cavitation is considered. Results show that at high speed, a deep, circular texture is better when cavitation does not occur, and a shallow triangular texture is recommended when cavitation occurs; a textured side wall can reduce the maximum temperature of the seal face by about 10 °C. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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19 pages, 5268 KiB

Open AccessArticle

Analysis of the Load-Bearing Characteristics of Gas-Extruded Membrane Bearings Based on the Alternating Direction Implicit Method

by Dongming Li, Feng Wang, Ruize Ma, Weidong Guo, Ziyi Shan and Kuipeng Zhao

Lubricants 2023, 11(8), 320; https://doi.org/10.3390/lubricants11080320 - 28 Jul 2023

Cited by 1 | Viewed by 1209

Abstract

In this study, a novel gas-extruded membrane bearing was developed, and an optimization algorithm was applied to solve a Reynolds equation that describes the load-bearing characteristics of this bearing. This was effective in improving the solution rate of the Reynolds equation, significantly reducing [...] Read more.

In this study, a novel gas-extruded membrane bearing was developed, and an optimization algorithm was applied to solve a Reynolds equation that describes the load-bearing characteristics of this bearing. This was effective in improving the solution rate of the Reynolds equation, significantly reducing the difficulty of obtaining a solution, avoiding high programming difficulty, and achieving a high solution accuracy. Through a comparative analysis, the error in the accuracy of the alternating implicit difference method was addressed, and the traditional finite element method for solving the same model was verified, with an average error of 2% reached to verify its applicability. The algorithm was also used to analyze the load-bearing capacity of the gas-extruded membrane bearing. This revealed not only a positive correlation of the average load-bearing capacity of the gas-extruded membrane bearing with the frequency and amplitude of vibration but also a negative correlation with radial clearance, with the cut-off frequency reaching 19 Khz. The load-bearing capacity of the gas-extruded membrane bearing proposed in this paper reached 1.28 N, which indicated an error of 3.28% with the theoretical approach. To sum up, this research provides an important reference for the design and manufacture of novel gas-extruded membrane bearings. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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12 pages, 3601 KiB

Open AccessArticle

Key Technologies and Design Methods of Ultra-Precision Aerostatic Bearings

by Zhongpu Wen, Hui Gu and Zhaoyao Shi

Lubricants 2023, 11(8), 315; https://doi.org/10.3390/lubricants11080315 - 25 Jul 2023

Cited by 3 | Viewed by 1282

Abstract

Precision measurement technology and instruments are the basis for high-quality development in modern industry. With the specialization of supporting facilities, ultra-precision motion guidance has become a core technology to achieve ultra-precision measurement. Aerostatic bearings have the advantages of low friction and high precision, [...] Read more.

Precision measurement technology and instruments are the basis for high-quality development in modern industry. With the specialization of supporting facilities, ultra-precision motion guidance has become a core technology to achieve ultra-precision measurement. Aerostatic bearings have the advantages of low friction and high precision, and are gradually playing an irreplaceable role in precision measurement and instruments. This paper summarizes and puts forward two contradictions for improving the loading capacity of aerostatic bearings, and investigates how to solve them via structural design. This paper analyzes the characteristics of the engineering calculation method, the gauge pressure ratio method, the gas resistance calculation method, and the AFVM (adaptive finite volume method) proposed. Finally, this paper summarizes the application scope of each method, gives solutions to the core problems, and outlines the developing trends. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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Review

Jump to: Research

22 pages, 3420 KiB

Open AccessReview

A Review on the Dynamic Performance Studies of Gas Foil Bearings

by Chaozhe Jin, Changlin Li and Jianjun Du

Lubricants 2024, 12(7), 262; https://doi.org/10.3390/lubricants12070262 - 22 Jul 2024

Cited by 1 | Viewed by 1053

Abstract

Gas foil bearings have important and wide applications in high-speed turbomachinery, generating low frictional lubricating gas film in series with underlying elastic foil structures to support the rotor system. Their dynamic performance is of vital significance in maintaining the rotor stability as well [...] Read more.

Gas foil bearings have important and wide applications in high-speed turbomachinery, generating low frictional lubricating gas film in series with underlying elastic foil structures to support the rotor system. Their dynamic performance is of vital significance in maintaining the rotor stability as well as in depressing rotor vibrations. This paper conducts a comprehensive review on dynamic performance studies conducted on gas foil bearings, including research on the dynamic stiffness and damping coefficients, bearing stability, nonlinear vibrations of the rotor–bearing system, and active methods for controlling rotor dynamic motions. This review provides clear observations towards the developments and iterations of the models, methods, and experiments of these studies. Full article

(This article belongs to the Special Issue Gas Lubrication and Dry Gas Seal)

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