scholarly journals Prediction Model of the Fusion Microzone on Sliding Contact Surface

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Yan Lu ◽  
Zuomin Liu
Keyword(s):  
Prediction Model ◽  
Temperature Rise ◽  
Function Method ◽  
Grid Method ◽  
Sliding Contact ◽  
Current Paper ◽  
Frictional Heat ◽  
Sliding Velocity ◽  
Key Points ◽  
Main Factor

The current paper is motivated by the need to understand the factors in generating the fusion microzone in sliding systems. The objectives are to analyze the different elements' varied influence on the engineering surface's temperature rise. The current paper developed the prediction model based on the thermal conduct theory. A solution based on the Green's function method is combined with the grid method for calculating the temperature rise and distribution. The research indicates that: frictional heat is closely related to the sliding velocity, its value is in proportion to the sliding velocity; the thermal properties of the material are one of the key points to decide the temperature rise; the load is another main factor in increasing the temperature rise; comparing with other elements, the roughness may be the least effective to the temperature rise.

Thermal Effects Due to Surface Films in Sliding Contact

1994 ◽  
Vol 116 (2) ◽  
pp. 238-245 ◽  
Author(s):  
Brian Vick ◽  
L. P. Golan ◽  
M. J. Furey
Keyword(s):  
Thermal Properties ◽  
Temperature Rise ◽  
Thermal Effects ◽  
Three Dimensional ◽  
Sliding Contact ◽  
Frictional Heat ◽  
Solution Technique ◽  
Surface Films ◽  
Thermal Coupling ◽  
Efficient Manner

The present work examines theoretically the influence of surface coatings on the temperatures produced by friction due to sliding contact. A generalized thermal model is developed which incorporates three-dimensional, transient heat transfer between layered media with thermal coupling at multiple, interacting contact patches. A solution technique based on a variation of the boundary element method is developed and utilized. The method allows for the solution of the distribution of frictional heat and the resulting temperature rise in an accurate yet numerically efficient manner. Results are presented showing the influence of film thickness, thermal properties, velocity, and contact area on the division of heat and surface temperature rise. The results show that a film with thermal properties different than those of the substrate can have a pronounced effect on the predicted temperature rise.

Maximum and Average Flash Temperatures in Sliding Contacts

1994 ◽  
Vol 116 (1) ◽  
pp. 167-174 ◽  
Author(s):  
Xuefeng Tian ◽  
Francis E. Kennedy
Keyword(s):  
Temperature Rise ◽  
Entire Range ◽  
Function Method ◽  
Approximate Solutions ◽  
Sliding Contact ◽  
Heat Sources ◽  
Flash Temperature ◽  
Infinite Body ◽  
Average Surface ◽  
Heat Partition

The surface temperature rise for a semi-infinite body due to different moving heat sources is analyzed for the entire range of Peclet number using a Green’s function method. Analytical and approximate solutions of maximum and average surface temperatures are obtained for the cases of square uniform, circular uniform, and parabolic heat sources. Considering the heat partition between the two contacting bodies, solutions of interface flash temperature are presented for the general sliding contact case as well as for the case of sliding contact between two moving asperities.

Temperature Rise Simulation of Three-Dimensional Rough Surfaces in Mixed Lubricated Contact

1998 ◽  
Vol 120 (2) ◽  
pp. 310-318 ◽  
Author(s):  
Liangheng Qiu ◽  
Herbert S. Cheng
Keyword(s):  
Temperature Rise ◽  
Surface Film ◽  
Computing Time ◽  
Three Dimensional ◽  
Film Surface ◽  
Grid Method ◽  
Lubricant Film ◽  
Frictional Heat ◽  
Asperity Contact ◽  
Lubricated Contact

A numerical simulation of the temperature rise for a three-dimensional rough surface sliding against a smooth surface in mixed lubricated contact has been developed. The effects of lubricant film friction and solid asperity friction are considered in the simulation. The moving grid method, which greatly reduces the required computer memory size and computing time, is used to solve the coefficient matrix of temperature equations. The time-dependent surface temperature rise at very small subregions is obtained. Different friction coefficients for lubricant shearing, surface film shearing and dry solid asperity contact are used to simulate the change of frictional heat in mixed lubricated contact. A critical temperature criterion is used to determine whether the friction coefficient is controlled by lubricant film, surface film, or dry solid asperity contact. Solutions for different contact conditions are presented for verification of the present simulation

scholarly journals Semi-analytical transient solutions of fully thermomechanical coupled problem for sliding contact

2018 ◽  
Vol 19 (4) ◽  
pp. 405
Author(s):  
Zijun An ◽  
Pengfei Sun
Keyword(s):  
Temperature Rise ◽  
Frictional Coefficient ◽  
Sliding Contact ◽  
Thermomechanical Coupling ◽  
Sliding Velocity ◽  
Low Velocity ◽  
Central Difference ◽  
Displacement Potential ◽  
Transient Solutions ◽  
Equivalent Method

The semi-analytical transient solutions of fully thermomechanical coupling for sliding contact have been deduced by using the plane-point heat source equivalent method, the thermoelastic displacement potential and the central difference method. To improve the calculated efficiency, the discrete convolution and fast Fourier transform are applied. The effects of coupled term, sliding velocity, frictional coefficient and initial temperature on temperature rise and the influence of thermal behavior on stress are studied. Results indicate that the coupled term can significantly affect the temperature rise for high velocity and it can be ignored for low velocity; the temperature rise is sensitive to the sliding velocity and the frictional coefficient; the Mises stress on the contact patch is decreased when considering thermal effect.

New Measurement Concept of Nanometer-Level Defects on Si Wafer Surface by Using Micro Contact Sensor

2012 ◽  
Vol 497 ◽  
pp. 137-141 ◽  
Author(s):  
Wen Jian Lu ◽  
Yuki Shimizu ◽  
Wei Gao
Keyword(s):  
Temperature Rise ◽  
Electric Circuit ◽  
Frictional Heat ◽  
Wafer Surface ◽  
Fem Model ◽  
Element Simulation ◽  
Type Contact ◽  
Contact Sensor ◽  
Measurement Concept ◽  
Si Wafer

A thermal-type contact sensor was proposed to detect small defects, the heights of which are less than 16 nm, on the wafer surface. The feasibility of the contact sensor, which detects frictional heat generated at the contact, was theoretically investigated focusing on the temperature rise of the sensor element. Simulation results with both the simple model of heat transfer and the FEM model showed that the expected temperature rise of the contact sensor is enough to be detected by the conventional electric circuit.

Analytical Modeling and Experimental Validation of Heating at the Leaf Seal/Rotor Interface

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Michael J. Pekris ◽  
Gervas Franceschini ◽  
Andrew K. Owen ◽  
Terry V. Jones ◽  
David R. H. Gillespie
Keyword(s):  
Mass Flow Rate ◽  
Analytical Model ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Rise ◽  
Thermal Characteristic ◽  
Frictional Heat ◽  
Test Facility ◽  
Engine Operation ◽  
Secondary Air

The secondary air system of a modern gas or steam turbine is configured to satisfy a number of requirements, such as to purge cavities and maintain a sufficient flow of cooling air to key engine components, for a minimum penalty on engine cycle efficiency and specific fuel consumption. Advanced sealing technologies, such as brush seals and leaf seals, are designed to maintain pressures in cavities adjacent to rotating shafts. They offer significant reductions in secondary air parasitic leakage flows over the legacy sealing technology, the labyrinth seal. The leaf seal comprises a series of stacked sheet elements which are inclined relative to the radial direction, offering increased axial rigidity, reduced radial stiffness, and good leakage performance. Investigations into leaf seal mechanical and flow performance have been conducted by previous researchers. However, limited understanding of the thermal behavior of contacting leaf seals under sustained shaft contact has led to the development of an analytical model in this study, which can be used to predict the power split between the leaf and rotor from predicted temperature rises during operation. This enables the effects of seal and rotor thermal growth and, therefore, implications on seal endurance and rotor mechanical integrity to be quantified. Consideration is given to the heat transfer coefficient in the leaf pack. A dimensional analysis of the leaf seal problem using the method of extended dimensions is presented, yielding the expected form of the relationship between seal frictional power generation, leakage mass flow rate, and rotor temperature rise. An analytical model is derived which is in agreement. Using the derived leaf temperature distribution formula, the theoretical leaf tip temperature rise and temperature distributions are computed over a range of mass flow rates and frictional heat values. Experimental data were collected in high-speed tests of a leaf seal prototype using the Engine Seal Test Facility at Oxford University. These data were used to populate the analytical model and collapsed well to confirm the expected linear relationship. In this form, the thermal characteristic can be used with predictions of mass flow rate and frictional power generated to estimate the leaf tip and rotor temperature rise in engine operation.

Temperature Rise at the Sliding Contact Interface for a Coated Semi-Infinite Body

1993 ◽  
Vol 115 (1) ◽  
pp. 1-9 ◽  
Author(s):  
X. Tian ◽  
F. E. Kennedy
Keyword(s):  
Surface Temperature ◽  
Temperature Rise ◽  
Peclet Number ◽  
Integral Transform ◽  
Sliding Contact ◽  
Contact Interface ◽  
Péclet Number ◽  
Maximum Surface ◽  
Semi Empirical ◽  
Maximum Surface Temperature

In this paper, a three-dimensional model of a semi-infinite layered body is used to predict steady-state maximum surface temperature rise at the sliding contact interface for the entire range of Peclet number. A set of semi-empirical solutions for maximum surface temperature problems of sliding layered bodies is obtained by using integral transform, finite element, heuristic and multivariable regression techniques. Two dimensionless parameters, A and Dp, which relate to coating thickness, contact size, sliding speed and thermal properties of both coating and substrate materials, are found to be the critical factors determining the effect of surface film on the surface temperature rise at a sliding contact interface. A semi-empirical solution for maximum surface temperature problems of homogeneous bodies, which covers the whole range of Peclet number, is also obtained.

A three-dimensional fusion prediction model for fractal rough surfaces in the sliding contact process

2014 ◽  
Vol 66 (3) ◽  
pp. 459-467
Author(s):  
Yan Lu ◽  
Zuomin Liu
Keyword(s):  
Temperature Rise ◽  
Rough Surfaces ◽  
Normal Load ◽  
Contact Process ◽  
Three Dimensional ◽  
Contact Problems ◽  
Sliding Contact ◽  
Content Type ◽  
Solution Methods ◽  
Account Temperature

Purpose – The purpose of this manuscript is to analyze the fusion micro-zone generated by typical rough surfaces and investigate the factors of thermal effects on the tribological performance of surface asperities and its results verified by the experiment. Design/methodology/approach – A three-dimensional fractal rough surfaces sliding contact model has been developed, which takes into account temperature rise and distribution. The finite-element method, Green's function method, thermal conduct theory and contact mechanics are used as the solution methods. Findings – The results yield insights into the effects of the sliding velocity, thermal properties of the material, normal load and surface roughness on the temperature rise of the sliding contact surface. It allows the specification of working conductions' properties to reduce fusion. Originality/value – The model is developed and described by using the features of the contact between one flat surface and one rough surface with varied topographies. It can be easily applied for solving the sliding contact problems with different working conditions and specified for designing the surface accuracy in the severe working condition.

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