Analysis of Thermal Effects in the Yield Phase of Hydrodynamic Lubricant Film in Plane Strain Forging

1996 ◽  
Vol 118 (4) ◽  
pp. 880-885 ◽  
Author(s):  
V. K. Bhatt ◽  
D. K. Sengupta
Keyword(s):  
Film Thickness ◽  
Plane Strain ◽  
Peclet Number ◽  
Film Formation ◽  
Dominant Role ◽  
Lubricant Film ◽  
Pressure Gradients ◽  
Lubricant Film Thickness ◽  
Péclet Number ◽  
Shear Energy

A thermal Reynolds equation, which takes into account viscosity variation across the lubricant film thickness due to shear energy dissipation within the film, has been developed. It also takes into account the effect of conduction and convection on heat transfer in the lubricant film. It indicates that the pressure gradients developed in a no-slip lubricated contact are increased with an increase in Peclet number. The use of the equation is illustrated by applying it in the film formation process in the yield phase of liquid lubricated plane strain forging. The analysis indicates that the Peclet number plays a dominant role infixing the lubricant film thickness in such contacts.

Thermal Analysis of Flow in the Deformation Phase of Liquid Lubricated Plane Strain Forging

2000 ◽  
Vol 122 (4) ◽  
pp. 746-751 ◽  
Author(s):  
V. K. Bhatt
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Film Thickness ◽  
Incompressible Fluid ◽  
Plane Strain ◽  
Simple Form ◽  
Energy Equation ◽  
Film Formation ◽  
Lubricant Film Thickness ◽  
Deformation Phase

The generalized energy equation is reduced into a simple form for conduction and convection modes of heat transfer across a hydrodynamic incompressible fluid film in the deformation phase of plane-strain forging. Expressions for the temperature, velocity, and flow distributions are obtained by solving the energy equation with appropriate boundary conditions. Application of this analysis is illustrated for the film formation process in the deformation phase of liquid lubricated plane strain forging. The analysis indicates that the Peclet number plays an important role in deciding the variation of lubricant film thickness with position and time in the deformation phase. [S0742-4787(00)02504-2]

scholarly journals On the Temperature and Lubricant Film Thickness Distribution in EHL Contacts with Arbitrary Entrainment

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 101 ◽  
Author(s):  
Milan Omasta ◽  
Jakub Adam ◽  
Petr Sperka ◽  
Ivan Krupka ◽  
Martin Hartl
Keyword(s):  
Film Thickness ◽  
Thermal Effects ◽  
Film Formation ◽  
Thickness Distribution ◽  
Thickness Measurement ◽  
Lubricant Film ◽  
Operating Conditions ◽  
Lubricant Film Thickness ◽  
Machine Parts ◽  
Film Thickness Measurement

An understanding of mechanisms which are responsible for elastohydrodynamic lubricant film formation under high sliding conditions is necessary to increase durability of machine parts. This work combines thin-film colorimetric interferometry for lubricant film thickness measurement and infrared microscopy for in-depth temperature mapping through the contact. The results describe the effect of operating conditions such as speed, slide-to-roll ratio, ambient temperature, and sliding direction on lubricant film thickness and temperature distribution. Film thickness data shows how much the film shape is sensitive to operating conditions when thermal effects are significant, while the temperature profiles provides an explanation of this behavior.

A Thermal Reynolds Equation and Its Application in the Analysis of Plasto-Hydrodynamic Inlet Zones

1974 ◽  
Vol 96 (4) ◽  
pp. 572-577 ◽  
Author(s):  
W. R. D. Wilson ◽  
S. M. Mahdavian
Keyword(s):  
Energy Dissipation ◽  
Film Thickness ◽  
Reynolds Equation ◽  
Wire Drawing ◽  
Lubricant Film ◽  
Pressure Gradients ◽  
Lubricant Film Thickness ◽  
Strip Rolling ◽  
Deformation Processes ◽  
Lubricated Contact

An equation which is equivalent to the steady, one-dimensional incompressible Reynolds equation but which takes account of viscosity variations across the lubricant film thickness due to energy dissipation within the film is developed. It indicates that the pressure gradients developed in a lubricated contact are reduced by the influence of energy dissipation. The use of the equation is illustrated by applying it in the analysis of the inlet zones of continuous deformation processes such as strip rolling and strip and wire drawing. The analysis indicates that thermal effects play an important role in deciding the lubricant film thickness in such contacts.

Film formation in EHL contacts with oil-impregnated sintered materials

2018 ◽  
Vol 70 (4) ◽  
pp. 612-619 ◽  
Author(s):  
Milan Omasta ◽  
Martin Ebner ◽  
Petr Šperka ◽  
Thomas Lohner ◽  
Ivan Krupka ◽  
...  
Keyword(s):  
Film Thickness ◽  
Sintered Material ◽  
Film Formation ◽  
Elastohydrodynamic Lubrication ◽  
Lubricant Film ◽  
Operating Conditions ◽  
Lubricant Film Thickness ◽  
Content Type ◽  
Film Forming ◽  
Highly Loaded

PurposeThe purpose of this study is to investigate lubricant film-forming capability of oil-impregnated sintered material in highly loaded non-conformal contacts. This self-lubrication mechanism is well described in lightly loaded conformal contacts such as journal bearings; however, only a little has been published about the application to highly loaded contacts under elastohydrodynamic lubrication regime (EHL).Design/methodology/approachThin film colorimetric interferometry is used to describe the effect of different operating conditions on lubricant film formation in line contacts.FindingsUnder fully flooded conditions, the effect of porous structure can be mainly traced back to the different elastic properties. When the contact is lubricated only by oil bleeding from the oil-impregnated sintered material, starvation is likely to occur. It is indicated that lubricant film thickness is mainly governed by oil bleeding capacity. The relationship between oil starvation parameters corresponds well with classic starved EHL theory.Practical implicationsTo show practical, relevant limitations of the considered self-lubrication system, time tests were conducted. The findings indicate that EHL contact with oil-impregnated sintered material may provide about 40 per cent of fully flooded film thickness.Originality/valueFor the first time, the paper presents results on the EHL film-forming capability of oil-impregnated sintered material by measuring the lubricant film thickness directly. The present paper identifies the phenomena involved, which is necessary for the understanding of the behavior of this complex tribological system.

Study of Direct Measuring of Lubricant Condition in Rolling Element Bearings With Microcomputer Technique

1990 ◽  
Vol 112 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Dongchu Zhao
Keyword(s):  
Film Thickness ◽  
Strain Gage ◽  
Lubricant Film ◽  
Rolling Element Bearings ◽  
Main Program ◽  
Test Apparatus ◽  
Lubricant Film Thickness ◽  
Rolling Element ◽  
Lubricant Films ◽  
Flow Charts

A method for measuring the lubricant condition with strain gage in rolling element bearings and the instrument used are introduced. In order to illustrate the method and the instrument, the theory of measuring lubricant films in rolling element bearings using strain technique, test apparatus, microcomputer hardware as well as software, flow charts for the main program and subprograms, are first described in detail. In addition, the lubricant film thickness is measured for several different lubricants and results are compared with theoretical ones. It is demonstrated that using the method and the instrument introduced in this paper, one can measure the lubricant condition inside bearings very accurately.

scholarly journals An investigation into the oil transport and starvation of piston ring pack

2018 ◽  
Vol 233 (1) ◽  
pp. 112-124 ◽  
Author(s):  
SR Bewsher ◽  
M Mohammadpour ◽  
H Rahnejat ◽  
G Offner ◽  
O Knaus
Keyword(s):  
Film Thickness ◽  
Boundary Conditions ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Reverse Flow ◽  
Lubricant Film ◽  
Total Power ◽  
Lubricant Film Thickness ◽  
Piston Ring Pack ◽  
Ring Pack

In order to accurately predict the lubricant film thickness and generated friction in any tribological contact, it is important to determine appropriate boundary conditions, taking into account the oil availability and extent of starvation. This paper presents a two-dimensional hydrodynamic model of a piston ring pack for prediction of lubricant film thickness, friction and total power loss. The model takes into account starvation caused by reverse flow at the conjunctional inlet wedge, and applied to a ring pack, comprising a compression and scraper ring. Inlet boundaries are calculated for an engine cycle of a four-cylinder, four-stroke gasoline engine operating at 1500 r/min with conditions pertaining to the New European Drive Cycle. The analysis shows the two main sources of starvation: first, due to a physical lack of inlet meniscus and second, due to reverse flow at the inlet wedge significantly affecting the prevailing conditions from the generally assumed idealised boundary conditions. Such an approach has not hitherto been reported in literature.

Instrumented Engine Bearings for Lubricant Film Thickness Measurement

MTZ worldwide ◽  
2021 ◽  
Vol 83 (1) ◽  
pp. 28-37
Author(s):  
Henry Brunskill ◽  
Andrew Hunter ◽  
Hosung Nam ◽  
Junsik Park
Keyword(s):  
Film Thickness ◽  
Thickness Measurement ◽  
Lubricant Film ◽  
Lubricant Film Thickness ◽  
Film Thickness Measurement

Gear Tribology and Lubrication

2005 ◽  
pp. 19-38
Keyword(s):  
Film Thickness ◽  
Case History ◽  
Failure Modes ◽  
Gear Tooth ◽  
Lubricant Film ◽  
Flash Temperature ◽  
Lubricant Film Thickness ◽  
Film Lubrication

Abstract This chapter reviews the knowledge of the field of gear tribology and is intended for both gear designers and gear operators. Gear tooth failure modes are discussed with emphasis on lubrication-related failures. The chapter is concerned with gear tooth failures that are influenced by friction, lubrication, and wear. Equations for calculating lubricant film thickness, which determines whether the gears operate in the boundary, elastohydrodynamic, or full-film lubrication range, are given. Also, given is an equation for Blok's flash temperature, which is used for predicting the risk of scuffing. In addition, recommendations for lubricant selection, viscosity, and method of application are discussed. The chapter discusses in greater detail the applications of oil lubricant. Finally, a case history demonstrates how the tribological principles discussed in the chapter can be applied practically to avoid gear failure.

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