scholarly journals A mixed thermal elastohydrodynamic lubrication model of rotary lip seal

2020 ◽  
Vol 103 (1) ◽  
pp. 003685041988190
Author(s):  
Xiaokai Huang ◽  
Shouwen Liu ◽  
Chao Zhang
Keyword(s):  
Simulation Study ◽  
Elastohydrodynamic Lubrication ◽  
Fluid Viscosity ◽  
Asperity Contact ◽  
Influence Of Temperature ◽  
Lip Seal ◽  
Sealing Performance ◽  
Proposed Model ◽  
Influence Of Temperature On ◽  
Lubrication Models

Rotary lip seal is used in various applications where the rotation shaft needs to be sealed, such as hydraulic pumps, fuel pumps, camshafts, crankshafts, and so on. Many thermal elastohydrodynamic lubrication models of rotary lip seal have been introduced, and most of these models neglect the asperity contact. This article proposes a mixed thermal elastohydrodynamic lubrication model of rotary lip seal, in which the microstructure of sealing lip surface, influence of temperature on fluid viscosity, and deformation of lip surface, as well as the asperity contact, are taken into consideration. Simulation study is carried out, and the results show that the asperity contact should not be neglected for analyzing the sealing performance of the rotary lip seal. The influence of speed on the sealing performance is also analyzed based on the proposed model.

scholarly journals Development of a dynamic model for photovoltaic modules and arrays

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 292-301
Author(s):  
Rodolfo Manuel Arias García ◽  
Ignacio Perez Abril
Keyword(s):  
Dynamic Model ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Data Sheet ◽  
Order Effects ◽  
Influence Of Temperature ◽  
Photovoltaic Modules ◽  
Proposed Model ◽  
Optical Effects ◽  
Influence Of Temperature On

In the work, a dynamic model is proposed in Simulink, to model the behavior of photovoltaic modules and arrays. A novel methodology is proposed to obtain exactly the five parameters of the simple diode model, through the data provided by the manufacturer in the data sheet. The model proposes the calculation of the Volt-Ampere curve from environmental conditions, solar irradiance, ambient temperature and second-order effects, such as: the influence of temperature on the photocurrent generated and on the open circuit voltage, as well as the spectral and optical effects. The validity and accuracy of the proposed model is checked by comparing its results, with curves and experimental data from the manufacturer's data sheet. In addition, curves of the module are shown, allowing to evaluate its behavior taking in to account the optical and spectral effects.

Mixed EHL numerical analysis and leakage experiment of skeleton reciprocating oil seal

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hua-Lin Yang ◽  
Xiulong Li ◽  
Weiwei Sun ◽  
Fang Deng ◽  
Jie Du
Keyword(s):  
Contact Pressure ◽  
Design Methodology ◽  
Elastohydrodynamic Lubrication ◽  
Deformation Analysis ◽  
Fluid Viscosity ◽  
Asperity Contact ◽  
Direct Proportion ◽  
Element Analysis ◽  
Content Type ◽  
Simulation Process

Purpose This paper aims to present the mixed elastohydrodynamic lubrication (EHL) model and obtain the leakage characteristics for the skeleton reciprocating oil seal. Design/methodology/approach The model consists of a finite element analysis of the contact pressure, a fluid mechanics analysis of the fluid film, a contact analysis of the asperity contact pressure, a deformation analysis of the seal lip and an iterative numerical simulation process. Findings Simulation results show that the leakage is in direct proportion to the seal roughness and speed, and in inverse proportion to the fluid viscosity. Comparisons with the experimental results verify the validity of the mixed EHL model. Originality/value This study provides a helpful method to calculate the leakage of the skeleton reciprocating oil seal, which shortens its development cycles.

scholarly journals The Grooved Lip Effect on Reciprocating Hydraulic Rod Seal Performances in Transient Condition: Elastohydrodynamic Lubrication

2020 ◽  
Vol 25 (2) ◽  
pp. 11-21
Author(s):  
Y. Bahi ◽  
M. El Gadari ◽  
M. Rahmoune
Keyword(s):  
Computational Models ◽  
Current Model ◽  
Elastohydrodynamic Lubrication ◽  
Axial Direction ◽  
Transient Condition ◽  
Slight Effect ◽  
Lip Seal ◽  
Sealing Performance ◽  
Pattern Shape ◽  
Average Film Thickness

AbstractIt is commonly known that the sealing performance of dynamic seals is significantly influenced by the surface finish. To reduce friction effect and leakage ratio, new generations of grooved lip or shaft have emerged, but only two computational models were performed up to now with a textured elastomeric lip: spiral groove in the axial direction or micro-cavities according to the circumferential direction. However, if the numerical results have confirmed the slight effect of the grooved lip on the rotary lip seal performances, it seems relevant to investigate the influence of such grooves on the reciprocating hydraulic rod seal behavior.Thus, the scope of this work is to perform a parametric study of the grooved lip throughout a one-dimensional elastohydrodynamic model by taking into account the elasticity of the lip and the shaft roughness.After confirming the validity of the current model, numerical simulations have been performed and compared with experiments. The effect of lip grooves on the hydraulic rod seal behavior in outstroke and instroke shaft motion has been underlined. Thereby, it is shown that the leakage and the average film thickness are sensible to both the depth and the density of the lip groove. Additionally, a slight effect of the pattern shape is observed on the friction force.

A Mixed Soft Elastohydrodynamic Lubrication Model With Interasperity Cavitation and Surface Shear Deformation

1999 ◽  
Vol 122 (1) ◽  
pp. 308-316 ◽  
Author(s):  
Fanghui Shi ◽  
Richard F. Salant
Keyword(s):  
Contact Problem ◽  
Unique Solution ◽  
Hydrodynamic Lubrication ◽  
Elastohydrodynamic Lubrication ◽  
Asperity Contact ◽  
Rigid Surface ◽  
Shear Deformations ◽  
Elastic Surface ◽  
Surface Shear ◽  
Lip Seal

A deterministic mixed lubrication model, governing the interface between a moving smooth rigid surface and a stationary rough elastic surface, has been developed. Both the normal and shear deformations of the elastic surface are considered, as well as interasperity cavitation. Utilizing an analogy between the hydrodynamic lubrication (with cavitation) problem and the asperity contact problem, a generalized computational formulation is derived and a unique solution scheme constructed to solve these seemingly different problems. The model has been applied to the rotary lip seal, and used to predict the performance characteristics over a range of shaft speeds. [S0742-4787(00)04101-1]

scholarly journals Mixed elastohydrodynamic lubrication model of rotary lip seal with non-Gaussian surfaces: experimentation verification and numerical analysis on effects of sealed pressure

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110170
Author(s):  
Di Liu ◽  
Shaoping Wang ◽  
Jian Shi
Keyword(s):  
Rough Surface ◽  
Fluid Pressure ◽  
Elastohydrodynamic Lubrication ◽  
Periodic Variation ◽  
Simulation Method ◽  
Height Distribution ◽  
Lip Seal ◽  
System A ◽  
Sealing Performance ◽  
Non Gaussian

Many published models can be used to analyse the sealing performance of rotary lip seal. The surfaces are normally assumed to be periodic variation. However, the quasi-randomness of surface height distribution should be considered, especially the non-Gaussian distribution. Hence, a mixed elastohydrodynamic lubrication model with non-Gaussian surfaces is proposed and used to analyse the effects of sealed fluid pressure on the seal performance in this paper. Based on digital filter and Johnson’s translator system, a rough surface simulation method is introduced to simulate non-Gaussian rough surface. Based on this method the mixed lubrication model with non-Gaussian surfaces is built. The proposed model is verified by comparing the simulation results to experimental observations. Furthermore, it is hardly to find the research focused on the effects of sealed pressure. Hence, the effects of sealed fluid pressure on the seal performance is focused.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

The Influence of Temperature on Successful Reproductions of Burbot, Lota Lota (L.) Under Hatchery Conditions

2010 ◽  
Vol 25 (1) ◽  
pp. 93-105 ◽  
Author(s):  
Daniel Żarski ◽  
Dariusz Kucharczyk ◽  
Wojciech Sasinowski ◽  
Katarzyna Targońska ◽  
Andrzej Mamcarz
Keyword(s):  
Lota Lota ◽  
Influence Of Temperature ◽  
Influence Of Temperature On
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