Heat Effects in Lubricating Films

1944 ◽  
Vol 11 (2) ◽  
pp. A72-A76
Author(s):  
A. C. Hagg
Keyword(s):  
Heat Flow ◽  
Temperature Dependence ◽  
Heat Generation ◽  
Simple Shear ◽  
Shearing Stress ◽  
Bearing Surface ◽  
Oil Film ◽  
Analytical Results ◽  
Heat Effects ◽  
Lubricant Viscosity

Abstract Heat effects in lubricating films are analyzed on the basis of simple shear of the lubricant, Reynolds logarithmic formula relating lubricant viscosity and temperature, and an equation relating the heat generation and heat flow in the film. The film-temperature dependence on velocity is determined, and the result is used to obtain the shearing stress and shearing rates. The formulas thus derived are useful in analyzing the performance of oil-film bearings. Experiments have been carried out with measurement of shaft- and bearing-surface temperatures, as well as friction; the tests support the analytical results. An approximate means for judging the importance of film heating in a given case in terms of velocity and lubricant viscosity is suggested.

Thermal regime of the lithosphere in the Canadian ShieldThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent.

2010 ◽  
Vol 47 (4) ◽  
pp. 389-408 ◽  
Author(s):  
Claire Perry ◽  
Carmen Rosieanu ◽  
Jean-Claude Mareschal ◽  
Claude Jaupart
Keyword(s):  
Heat Flow ◽  
Heat Generation ◽  
Seismic Refraction ◽  
Surface Heat ◽  
Canadian Shield ◽  
P Wave ◽  
Seismic Velocities ◽  
Flow Measurements ◽  
Surface Heat Flow ◽  
Mantle Heat Flow

Geothermal studies were conducted within the framework of Lithoprobe to systematically document variations of heat flow and surface heat production in the major geological provinces of the Canadian Shield. One of the main conclusions is that in the Shield the variations in surface heat flow are dominated by the crustal heat generation. Horizontal variations in mantle heat flow are too small to be resolved by heat flow measurements. Different methods constrain the mantle heat flow to be in the range of 12–18 mW·m–2. Most of the heat flow anomalies (high and low) are due to variations in crustal composition and structure. The vertical distribution of radioelements is characterized by a differentiation index (DI) that measures the ratio of the surface to the average crustal heat generation in a province. Determination of mantle temperatures requires the knowledge of both the surface heat flow and DI. Mantle temperatures increase with an increase in surface heat flow but decrease with an increase in DI. Stabilization of the crust is achieved by crustal differentiation that results in decreasing temperatures in the lower crust. Present mantle temperatures inferred from xenolith studies and variations in mantle seismic P-wave velocity (Pn) from seismic refraction surveys are consistent with geotherms calculated from heat flow. These results emphasize that deep lithospheric temperatures do not always increase with an increase in the surface heat flow. The dense data coverage that has been achieved in the Canadian Shield allows some discrimination between temperature and composition effects on seismic velocities in the lithospheric mantle.

Design and optimization of textures on the surface of crankpin bearing to improve lubrication efficiency and friction power loss of engine

2020 ◽  
pp. 135065012094200
Author(s):  
Zhenpeng Wu ◽  
Vanliem Nguyen ◽  
Vanquynh Le ◽  
Xuanlong Le ◽  
Vancuong Bui
Keyword(s):  
Power Loss ◽  
Asperity Contact ◽  
Bearing Surface ◽  
Film Pressure ◽  
Oil Film ◽  
Design And Optimization ◽  
Friction Power ◽  
Study Results ◽  
The Impact ◽  
Oil Film Pressure

The study proposes a design and optimization of textures on the surface of crankpin bearing to improve the lubrication efficiency and friction power loss (LE-FPL). A hydrodynamic lubrication model of crankpin bearing considering the impact of the external dynamic load and micro asperity contact is established. Based on the established model, the lubrication textures designed on the bearing surface are then simulated and optimized through the algorithms developed in Matlab environment and multi-objective optimization method. Increasing the oil film pressure and reducing the contact force ( Wac) in the asperity contact region, friction force ( Ff), and friction coefficient ( µ) of crankpin bearing are the objective functions to evaluate the LE-FPL. The study results indicate that the lubrication textures designed on the bearing surface have an obvious effect on improving the LE-FPL. Especially, with the optimized textures, the maximum oil film pressure is greatly increased by 44.8% while the maximum values of Wac and Ff are significantly reduced by 22% and 25%. Consequently, the lubrication textures added on the surface of crankpin bearing can greatly improve the LE-FPL.

Signature Analysis of Roller Bearing Vibrations: Lubrication Effects

1992 ◽  
Vol 206 (3) ◽  
pp. 193-202 ◽  
Author(s):  
Y-T Su ◽  
Y-T Sheen ◽  
M-H Lin
Keyword(s):  
Roller Bearing ◽  
Vibration Energy ◽  
Running Speed ◽  
Oil Film ◽  
Spacing Distribution ◽  
Surface Irregularities ◽  
Vibration Signature ◽  
Bearing Assembly ◽  
Bearing Vibration ◽  
Lubricant Viscosity

This study investigates the vibration signature of roller bearings, induced by the surface irregularities of components, under various lubricating conditions. The bearing vibration is modelled as the output of the bearing assembly which is subjected to the excitations of surface irregularities through the oil-film. The oil-film acts as a spring between the roller and race. The stiffness of oil-film under different lubricating conditions is studied from the empirical equation of minimum oil-film thickness. It is shown that the vibration spectra of a normal roller bearing may have a pattern of equal frequency spacing distribution (EFSD) whose frequency information is similar to that of a damaged bearing. Under large loading and low running speed, the vibration energy is low if the lubricant viscosity is high. On the other hand, at high running speed, the vibration energy is high with high lubricant viscosity.

Analysis of Oil Film Thickness on a Piston Ring of Diesel Engine: Effect of Oil Film Temperature

2001 ◽  
Author(s):  
Yasuo Harigaya ◽  
Michiyoshi Suzuki ◽  
Masaaki Takiguchi
Keyword(s):  
Diesel Engine ◽  
Temperature Distribution ◽  
Heat Flow ◽  
Film Thickness ◽  
Piston Ring ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Two Dimensional ◽  
Oil Film ◽  
The Mean

Abstract This paper describes that an analysis of oil film thickness on a piston ring of diesel engine. The oil film thickness has been performed by using Reynolds equation and unsteady, two-dimensional (2-D) energy equation with a heat generated from viscous dissipation. The temperature distribution in the oil film is calculated by using the energy equation and the mean oil film temperature is computed. Then the viscosity of oil film is estimated by using the mean oil film temperature. The effect of oil film temperature on the oil film thickness of a piston ring was examined. This model has been verified with published experimental results. Moreover, the heat flow at ring and liner surfaces was examined. As a result, the oil film thickness could be calculated by using the viscosity estimated from the mean oil film temperature and the calculated value is agreement with the measured values.

Heat generation of plutonic rocks and continental heat flow provinces

1968 ◽  
Vol 5 ◽  
pp. 1-12 ◽  
Author(s):  
Robert F. Roy ◽  
David D. Blackwell ◽  
Francis Birch
Keyword(s):  
Heat Flow ◽  
Heat Generation ◽  
Plutonic Rocks

[i][/i]THE IMPACT OF MICROGEOMETRY BEARING SURFACE OF THE PISTON ON THE PARAMETERS OF OIL FILM

2016 ◽  
Vol 23 (2) ◽  
pp. 431-436 ◽  
Author(s):  
Emil Wróblewski ◽  
Antoni Iskra ◽  
Maciej Babiak
Keyword(s):  
Bearing Surface ◽  
Oil Film ◽  
The Impact
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