Oil Film Damping Analysis in Non-Newtonian Transient Thermal Elastohydrodynamic Lubrication for Gear Transmission

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Zeliang Xiao ◽  
Zuodong Li ◽  
Xi Shi ◽  
Changjiang Zhou
Keyword(s):  
Thermal Effect ◽  
Rotation Speed ◽  
Impact Resistance ◽  
Elastohydrodynamic Lubrication ◽  
Tangential Direction ◽  
Maximum Temperature ◽  
Spur Gears ◽  
Oil Film ◽  
Tooth Number ◽  
Transient Thermal

The models of normal and tangential oil film damping are established by modeling the viscous-elastic fluid as massless damping elements. The central pressure and film thickness distributions, friction coefficient, and maximum temperature rise with or without considering thermal effect indicate the proposed damping models and the solutions to the damping are valid. Thereafter, the thermal effect on oil film damping is discussed and the effects of contact force, rotation speed, and tooth number of spur gears in line contact non-Newtonian transient thermal elastohydrodynamic lubrication (EHL) on the oil film damping are investigated. The results imply that the larger damping in the normal direction is beneficial to meshing impact resistance and vibration reduction, whereas the smaller damping in the tangential direction is very helpful for fluidity enhancement and friction heat inhibition.

Relationship Between Temperature Distribution in EHL Film and Dimple Formation

2005 ◽  
Vol 127 (3) ◽  
pp. 658-665 ◽  
Author(s):  
Kazuyuki Yagi ◽  
Keiji Kyogoku ◽  
Tsunamitsu Nakahara
Keyword(s):  
Phase Transition ◽  
Experimental Study ◽  
Temperature Distribution ◽  
Elastohydrodynamic Lubrication ◽  
Infrared Emission ◽  
Maximum Temperature ◽  
Oil Film ◽  
Sliding Direction ◽  
Oil Flow ◽  
Ball Surface

This paper describes an experimental study on dimple formation under elastohydrodynamic lubrication (EHL) conditions. The oil film thickness between a ball surface and a glass disk was measured using optical interferometry, and the temperatures of both the surfaces and of the oil film averaged across it were measured using an infrared emission technique. It was found that the temperature profile across the oil film varies abruptly along the sliding direction, and the Couette flow decreases due to the viscosity wedge action as the oil flow is close to the dimple zone. The maximum temperature rise in the dimple zone sometimes reached over 400 K, thus, the phase transition of the oil from liquid to glass may not occur.

scholarly journals Demand Analysis of Lubricating Oil in Spur Gear Pairs

2020 ◽  
Vol 10 (16) ◽  
pp. 5417
Author(s):  
Fuchun Jia ◽  
Yulong Lei ◽  
Yao Fu ◽  
Binyu Wang ◽  
Jianlong Hu
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Spur Gear ◽  
Lubricating Oil ◽  
Transmission Ratio ◽  
Spur Gears ◽  
Control Variate ◽  
Tooth Number ◽  
Oil Demand ◽  
Meshing Process ◽  
Input Torque

Theoretical calculation and numerical simulation are used to investigate the lubricating oil demand of spur gears. In accordance with the function of lubricating oil during the meshing process, oil demand is regarded as the superposition of oil for lubrication and cooling. Oil for lubrication is calculated in accordance with meshing and elastohydrodynamic lubrication (EHL) theories. Oil for cooling is obtained from friction heat. The influence of different meshing positions on lubricating oil demand is analysed, and the effects of modulus, tooth number, transmission ratio, input speed and input torque on lubricating oil demand is investigated using a control variate method. Simulation results indicated that oil for lubrication and oil for cooling have two maxima each during a meshing circle. The influences of different gear parameters and working conditions on lubricating oil demand are compared. The results showed that the oil volume for lubrication increases and oil volume for cooling decreases as the modulus, tooth number and transmission ratio of the gear increase, the oil volume for lubrication and oil volume for cooling increases as the input speed and input torque increase.

Relationship Between Temperature Distribution in EHL Film and Dimple Formation

2004 ◽  
Author(s):  
Kazuyuki Yagi ◽  
Keiji Kyogoku ◽  
Tsunamitsu Nakahara
Keyword(s):  
Phase Transition ◽  
Experimental Study ◽  
Temperature Distribution ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Infrared Emission ◽  
Maximum Temperature ◽  
Oil Film ◽  
Oil Flow ◽  
Ball Surface

This paper describes an experimental study on dimple formations under elastohydrodynamic lubrication (EHL) conditions. The oil film thickness between a ball surface and a sapphire disk was measured using optical interferometry and the temperatures of both the surfaces and of the oil film averaged across it were measured by an improved infrared emission technique. It was found that temperature profile across the oil film varies abruptly along the direction of the oil film thickness and the Couette flow decreases due to the viscosity wedge action as the oil flow is close to the dimple zone. The maximum temperature rise in the dimple zone sometimes reached above 400 K and thus the phase transition of the oil from liquid to glass may not occur.

Transient Thermal Lubrication Analysis of Involute Gear

2010 ◽  
Author(s):  
Wen-zhong Wang ◽  
Jibin Hu ◽  
Hong Cao ◽  
Yuan-zhong Hu
Keyword(s):  
Thermal Effect ◽  
High Speed ◽  
Equation System ◽  
Vital Role ◽  
Spur Gears ◽  
Transient Effect ◽  
Lubrication Performance ◽  
Elliptical Contact ◽  
Lubrication Characteristics ◽  
Transient Thermal

With the development of modern machine, the gear sets have to operate under high power high revolution; lubrication performance plays a vital role to the gear sets. In this study, lubrication analysis of spur gears under high speed is conducted based on the elliptical contact and unified Reynolds equation system model. The transient effect and thermal effect are taken into considered. The results show that the transient effect strongly influences the lubrication characteristics during the mesh cycle, while thermal effect enhances the transient effect.

Thermoelastohydrodynamic Analysis of Journal Bearings With Non-Newtonian Carreau Fluids

2009 ◽  
Author(s):  
M. Mongkolwongrojn ◽  
C. Aiumpornsin
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Initial Conditions ◽  
Elastohydrodynamic Lubrication ◽  
Viscosity Model ◽  
Maximum Temperature ◽  
Approximation Technique ◽  
Low Elastic Modulus ◽  
Modified Reynolds Equation ◽  
Transient Thermal

The paper focuses on the solution of a numerical model to explore the journal bearing performance under transient thermal elastohydrodynamic lubrication with non-Newtonian lubricants based on Carreau viscosity model. The newly derived time-dependent modified Reynolds equation and the adiabatic energy equation have been formulated using a non-Newtonian Carreau viscosity model. The simultaneous systems consisting of the modified Reynolds equation, elasticity equation and energy equation with initial conditions were solved numerically using the multi-grid multi-level method with full approximation technique. The analysis showed that the fluid characteristics as defined by the Carreau model, led to large differences in minimum film thickness and maximum temperature rise for bearing liners with low elastic modulus.

Transient Thermal Hydrodynamic Lubrication Analysis of Textured Piston Ring/Cylinder Liner

2018 ◽  
Vol 279 ◽  
pp. 172-178
Author(s):  
Sheng Gang Guo ◽  
Bin Wang ◽  
Qiu Ying Chang
Keyword(s):  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Maximum Temperature ◽  
Temperature Elevation ◽  
Factors Affecting ◽  
Oil Film ◽  
Factors Influencing ◽  
Main Factors ◽  
Transient Thermal

On the basis of transient thermal hydrodynamic lubrication (TTHL) simulation and isothermal hydrodynamic lubrication (IHL) simulation of textured piston ring/cylinder liner, main factors influencing oil film temperature, distribution of the maximum temperature, and comparison between two models were discussed. The results show that texturing improves hydrodynamic lubrication situations, and velocity of piston ring and applied load are two important factors affecting oil film temperature. Apart from that, sever temperature elevation is located at the export of oil film and textured areas. Although change trends of the maximum of pressure and the minimum of oil film thickness are basically the same, the values of them are different. Temperature is a necessary element for analyzing the lubricant situations of piston ring/cylinder liner.

scholarly journals The Piston Ring-Cylinder Bore Interface Leakage of Bent-Axis Piston Pumps Based on Elastohydrodynamic Lubrication and Rotation Speed

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lvjun Qing ◽  
Lichen Gu ◽  
Yan Wang ◽  
Wei Xue ◽  
Zhufeng Lei
Keyword(s):  
Film Thickness ◽  
Piston Ring ◽  
Rotation Speed ◽  
Elastohydrodynamic Lubrication ◽  
Oil Film ◽  
Proposed Model ◽  
Minimum Film Thickness ◽  
Oil Flow ◽  
Discharge Pressure ◽  
Cylinder Bore

The bent-axis piston pump is the core component of electrohydrostatic actuators (EHA) in aerospace applications, and its wear of key friction interfaces is greatly related to the healthy operation of pumps. The leakage of the piston ring-cylinder bore interface (PRCB), as the important part of the return oil flow of the pump house that commonly assesses the wear of key friction interfaces in piston pumps, is changed with the rotation speed. Thus, the wear of key friction interfaces is usually inaccurate by using the leakage of PRCB. In order to obtain the relationship between the PRCB leakage and the rotation speed, an elastohydrodynamic lubrication model is proposed. First, the proposed model includes a minimum film thickness model of PRCB to analyze the dynamic change of oil film of PRCB when subject to the elastohydrodynamic lubrication. After that, a mathematical model of PRCB is induced by combining the minimum film thickness model with the flow equation, which helps produce the effects of the oil film on the leakage of PRCB. The proposed model is verified by numerical simulation and experiment. The results show that the leakage of PRCB has a negative effect on the return oil flow of the pump case in the range of rotation speed of 700–1300 r/min and discharge pressure of 10–20 MPa. Furthermore, the leakage of PRCB is proportional to the rotation speed, but the return oil flow of the pump case is decreased. The effects of rotation speed are enhanced under the high discharge pressure conditions.

The Numerical Analysis of the Velocity and Pressure Distribution of the Oil Film in Heavy Hydrostatic Thrust Bearing

2014 ◽  
Vol 541-542 ◽  
pp. 658-662
Author(s):  
Jian Li ◽  
Yuan Chen ◽  
Yang Chun Yu ◽  
Zhu Xin Tian ◽  
Yu Huang
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Pressure Distribution ◽  
Working Conditions ◽  
Thrust Bearing ◽  
Rotation Speed ◽  
The Other ◽  
Surface Load ◽  
Oil Film ◽  
Volume Method

To study the velocity and pressure distribution of the oil film in a heavy hydrostatic thrust bearing, a mathematical model of the velocity is proposed and the finite volume method (FVM) has been used to simulate the flow field under different working conditions. Some pressure experiments were carried out and the results verified the correctness of the simulation. It is concluded that the pressure distribution varies small under different rotation speed when the surface load on the workbench is constant. But the velocity of the oil film is influenced greatly by the rotation speed. When the rotation speed of the workbench is as quick as enough, the velocity of the oil film on one radial side of the pad will be zero, that is to say the lubrication oil will be drained from the other three sides of the recess.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

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