Simulation of the effects of non-Newtonian fluid on the behavior of a step hydraulic rod seal based on a power law fluid model

Wang, Bing-qing; Peng, Xudong; Meng, Xiangkai

doi:10.1631/jzus.a1800096

Cited by 17 publications

(9 citation statements)

References 38 publications

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“…Further differences between experiments and simulations might result from neglecting phenomena such as friction [10,14], shear thinning [39], wall slip and wetting [40], viscoelasticity [41,42] and a conceivable temperature rise in the sealing gap [43]. Furthermore, even at ambient operating pressure, the pressure in the gap reaches a maximum of approximately 20 MPa.…”

Section: Current Limitationsmentioning

confidence: 99%

Remarks on Modeling the Oil Film Generation of Rod Seals

et al. 2021

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The oil film generation of a U-cup rod seal and the oil film thickness on the rod after outstroke were analyzed analytically, numerically, and experimentally. The analyzed sealing system consists of an unmodified, commercially available U-cup, a polished rod, and mineral oil. The inverse theory of hydrodynamic lubrication (IHL) and an elastohydrodynamic lubrication (EHL) model—both based on the Reynolds equation for thin lubricating films—were utilized to simulate the oil film generation. In the EHL analysis, physical parameters and numerical EHL parameters were varied. Both the analytical and numerical results for the varied parameters show that the film thickness follows a square-root function (i.e., with a function exponent of 0.5) with respect to the product of dynamic viscosity and rod speed, also referred to as the duty parameter. In comparison to the analytical and numerical results, the film thickness obtained via ellipsometry measurements is a function of the duty parameter with an exponent of approximately 0.85. Possible causes for the discrepancy between theory and experiments are discussed. A potential remedy for the modeling gap is proposed.

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Section: Current Limitationsmentioning

confidence: 99%

Remarks on Modeling the Oil Film Generation of Rod Seals

et al. 2021

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“…The GS sealing ring is composed of a step ring and an O-ring. The elastic force of the GS seal is generated by the amount of precompression of the O-ring, which places the step ring close to the sealing surface and plays a key sealing role [17].…”

Section: Hydro-pneumatic Spring Sealing Structurementioning

confidence: 99%

Simulation and Experimental Study on Sealing Characteristics of Hydro-Pneumatic Spring GS Seal Rings

Wang,

Liu,

et al. 2023

Applied Sciences

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Hydro-pneumatic springs often work under high pressure and alternating load conditions, which can easily cause seal damage, leakage, and serious failure. Relevant studies have shown that the dynamic seal failure of hydro-pneumatic springs is the main cause of hydro-pneumatic spring failure, and the sealing performance of GS sealing rings directly determines the service life of hydro-pneumatic springs. The influence of different sealing structure parameters on the sealing performance of GS sealing of hydro-pneumatic springs has been studied, which can provide effective theoretical guidance for the design of sealing structures related to hydro-pneumatic springs. However, the existing research on hydro-pneumatic springs mainly focuses on the characteristics of damping and stiffness; there is a relative lack of research on sealing performance and sealing structure, and the performance change law of GS seals under different working conditions is unclear. In this paper, a GS seal ring is selected as the main seal of the hydro-pneumatic spring, the material parameters of the GS seal ring are obtained via the single-axis compression test, and the finite element simulation method is used to establish the sealing model under different compression ratios of 10–30% and different pressure impacts of 5–30 MPa. By doing so, the stress nephogram, sealing ring shape, and sealing contact pressure of the GS sealing ring under different simulation parameters are obtained. From the test results, the decrease in compression ratio after the wear of the sealing ring is the main reason for the seal leakage of the hydro-pneumatic spring. The maximum contact stress of the sealing ring occurs at the lip of the step ring, and the maximum sealing pressure of the sealing ring is determined by the contact pressure of sealing surfaces II and III. The sealing performance of the GS-type combination sealing ring is affected by the compression ratio of the sealing ring and the impact pressure; when the compression ratio of the sealing ring is 15%, the sealing ring can meet the sealing work needs below 25 MPa. The research results provide a theoretical basis for the design of GS sealing of hydro-pneumatic springs and the effective improvement of the life and reliability of related equipment.

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“…The solid contact mechanism between two surfaces that are sliding relative to each other is quite complex and is not yet sufficiently known. 28 As the Greenwood-Williamson model is widely used in current studies of reciprocating seals, 7,[9][10][11][13][14][15][16][17][18][19][20] this contact model is also employed in this paper. A Gaussian distribution is assumed to exist for these asperities, and the solid contact pressure can be calculated by the Greenwood-Williamson contact model 29 :…”

Section: Contact Mechanismmentioning

confidence: 99%

“…In this method, FEA commercial software is used to obtain the macrostatic deformation, while the numerical procedure is applied to calculate the tribological characteristics, such as the film thickness, friction and leakage in the dynamic reciprocating motion. The coupling method has been widely employed in the study of single seals such as O-rings, [4][5][6][7][8][9] U-cup seals [10][11][12][13][14] and some combined seals such as Step seals 15,16 and VL seals. [17][18][19][20] However, the above studies focused mainly on the sealing performance under normal temperature conditions, while little research has been conducted on the sealing performance in a wide temperature range.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the tribological performance of reciprocating seals in a wide temperature range

Peng

Ouyang

Schmitz

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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Reciprocating seals are widely used in general industrial machines and are designed to endure rigorous working conditions. Among the harshest challenges, the wide temperature range they withstand has a significant influence on their sealing performance. However, most studies of reciprocating seals have focused only on their sealing characteristics at normal temperatures. To investigate the impacts of temperature on the seal's tribological performance, this paper examines the VL seal, a kind of combined seals, and discusses its performance in a wide temperature range. Material properties of the VL seal at temperatures from −55 °C to 135 °C are measured based on the seal product. The thermo-viscosity effect and the influence of thermal expansion and contraction are both considered in the reciprocating seal modelling. A coupling method that combines the finite-element analysis model with a mixed-lubrication procedure is implemented. For deformation calculation, a comparison between the influence coefficient method and the semi-infinite space method is conducted, and finds only minuscule disparities for the VL-seal analysis. To avoid the divergent problem due to high viscosity at low temperatures, this paper proposes the successive approaching method. Details of the sealing zone in the outstroke and instroke are systematically discussed in relation to a wide range of temperatures. The corresponding experiments are conducted and compared with the simulation. The results indicate that the temperature has a tremendous influence on the tribological performance. The leakage and the friction at the high temperature are much higher than those at the normal temperature.

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Simulation of the effects of non-Newtonian fluid on the behavior of a step hydraulic rod seal based on a power law fluid model

Cited by 17 publications

References 38 publications

Remarks on Modeling the Oil Film Generation of Rod Seals

Remarks on Modeling the Oil Film Generation of Rod Seals

Simulation and Experimental Study on Sealing Characteristics of Hydro-Pneumatic Spring GS Seal Rings

Investigation of the tribological performance of reciprocating seals in a wide temperature range

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