Effect of a Surface Film on the Surface Temperature of a Rotating Cylinder

1986 ◽  
Vol 108 (1) ◽  
pp. 92-97 ◽  
Author(s):  
B. Gecim ◽  
W. O. Winer
Keyword(s):  
Thermal Properties ◽  
Heat Source ◽  
Film Thickness ◽  
Surface Temperature ◽  
Temperature Rise ◽  
High Speed ◽  
Integral Transform ◽  
Heat Conduction Problem ◽  
Surface Film ◽  
Layer Effect

Solution to the steady heat conduction problem of a rotating layered cylinder is presented. The governing differential equations (for the film and the substrate) are solved by using an integral transform technique. It is shown that the presence of a surface film measured in micrometers can substantially change the level of the surface temperature. The effect of the surface film on the surface temperature depends on: respective thermal properties of the film and the substrate; relative surface speed; heat source (contact) size; and surface film thickness. However, the range in which the effect of the film on the surface temperature is dependent on these parameters is limited. Outside this range (i.e., thin film/low speed or thick film/high speed) the surface temperature rise is determined by the thermal properties of the substrate, or by the properties of the film alone, respectively. Hence, outside this range, a further change in the film thickness does not influence the surface temperature rise. Dimensionless plots showing the change in surface temperature rise as a function of material thermal properties, surface speed, heat source size, and film thickness are presented. Behavior for specific material combinations are also presented. The present information can be utilized to predict the layer effect on the partition of heat between the layered cylinders.

Steady Temperature in a Rotating Cylinder Subject to Surface Heating and Convective Cooling

1984 ◽  
Vol 106 (1) ◽  
pp. 120-126 ◽  
Author(s):  
B. Gecim ◽  
W. O. Winer
Keyword(s):  
Heat Source ◽  
Peclet Number ◽  
High Speed ◽  
Integral Transform ◽  
The Body ◽  
Cooling Zone ◽  
Dimensionless Numbers ◽  
Péclet Number ◽  
Heating And Cooling ◽  
Simultaneous Heating

This study utilizes an integral transform technique in order to solve the heat conduction equation in cylindrical coordinates. The major assumption is the high speed (i.e., large Peclet number) assumption. The boundary value problem is governed by the parabolic form of the heat equation representing the quasi-stationary state. The boundary conditions are a combination of Neumann and mixed type due to simultaneous heating and cooling on the surface of the cylinder. The surface temperature reaches a peak value over the heat source and gradually decreases to a nearly constant level over the cooling zone. Thermal penetration in the radial direction is shown to be only a few percent of the radius, leaving the bulk of the body at a uniform temperature. The width of the heat source and the total heat input are shown to be effective on the level of temperature whereas the input distribution is shown to be unimportant. The dimensionless numbers involved are the Biot and the Peclet numbers where the solution is governed by the ratio of the Biot number to the square root of the Peclet number.

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.

Investigations of Transient Machined Workpiece Surface Temperature in High Speed Peripheral Milling Using Inverse Method

2012 ◽  
Vol 723 ◽  
pp. 14-19 ◽  
Author(s):  
Zhan Qiang Liu ◽  
Fan Zhang ◽  
Fu Lin Jiang
Keyword(s):  
Heat Source ◽  
Surface Temperature ◽  
High Speed ◽  
Inverse Method ◽  
Moving Heat Source ◽  
Peripheral Milling ◽  
Machined Surface ◽  
Workpiece Temperature ◽  
Surface Temperatures ◽  
1045 Steel

In high speed machining, temperature distribution in workpiece is the main factor which directly affects the surface integrity and dimensional accuracy of machined workpiece. In this paper, the machined workpiece temperature in high speed peripheral milling is analyzed through using moving heat source method and inverse method. Firstly, the workpiece to be machined is considered as a semi-infinite solid to model the transient surface temperature using arc-shaped moving heat source. Inverse method is then applied for the calculating of heat flux. Peripheral milling experiments of 1045 steel is performed with coated carbide insert The machined surface temperatures were measured during experiments. The measured results were found to be in agreement with the predicted ones by transient models for machined surface temperatures. These results confirm the conclusion that the transient workpiece temperature will decline when the cutting speed increases to a critical value.

Prediction and Measurement of Surface Temperature Rise at the Contact Interface for Oscillatory Sliding

1995 ◽  
Vol 209 (1) ◽  
pp. 41-51 ◽  
Author(s):  
X Tian ◽  
F E Kennedy
Keyword(s):  
Heat Source ◽  
Surface Temperature ◽  
Temperature Rise ◽  
Frictional Heating ◽  
Temperature Model ◽  
Contact Interface ◽  
Simple Method ◽  
Sliding Motion ◽  
Thin Film Thermocouple ◽  
Temperature Solution

Surface temperature rise due to frictional heating in oscillatory sliding is studied using Green's function method and a recently developed temperature model for finite bodies. The surface temperature solution in oscillatory sliding differs in two respects from that in unidirectional sliding: the heat source is time varying and the sliding motion is periodic. The magnitude of the heat flux determines the local or flash temperature rise, which is cyclic owing to the time-dependent nature of the heat source. The periodic sliding movement of the heat source is found to be responsible for an additional surface temperature increase which can be considered as a nominal temperature rise. Based on a new surface temperature model for a finite contacting body, a relatively simple method for predicting the maximum surface temperature rise for an oscillatory sliding system is presented. Experimental measurements of surface temperature rise during oscillatory sliding were carried out using thin-film thermocouple (TFTC) techniques. The measured surface temperature rise at the contact interface agrees well with the model's predictions.

Circumferential Variations of Bore Heat Flux and Outside Surface Temperature for a Solar Collector Tube

1977 ◽  
Vol 99 (3) ◽  
pp. 360-366 ◽  
Author(s):  
E. M. Sparrow ◽  
R. J. Krowech
Keyword(s):  
Heat Flux ◽  
Thermal Properties ◽  
Surface Temperature ◽  
Outer Surface ◽  
Solar Collector ◽  
Heat Conduction Problem ◽  
Flow Conditions ◽  
Collector Plate ◽  
Closed Form Solutions ◽  
Large Heat

An analysis is made of the heat transfer processes in a solar collector tube subjected to large circumferential heat flux variations on its outer surface. The analysis is carried out for a collector plate configuration in which the tubes are situated in embossments in the otherwise flat surface of the plate. The solar energy absorbed by the collector plate is conducted to the tubes and gives rise to large heat flux spikes at discrete circumferential locations on the outer surface of a tube. The two-region heat conduction problem encompassing the embossed portion of the collector plate and the tube is solved by a novel procedure which provides closed form solutions of high numerical accuracy. The influence of system dimensions, thermal properties, and tube bore convection is examined by means of five dimensionless parameters, of which the Biot number was found to be the most important. The results showed that for realistic dimensions and thermal properties of the plate and tube, circumferential variations of the outside surface temperature and bore heat flux can be neglected, provided that the tube flow is laminar. For turbulent flow conditions, the variations in bore heat flux are substantially greater than for laminar flow.

A New OpenFOAM Solver Capable of Modelling Oil Jet-Breakup and Subsequent Film Formation for Bearing Chamber Applications

2019 ◽  
Author(s):  
Andrew Nicoli ◽  
Richard Jefferson-Loveday ◽  
Kathy Simmons
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
High Speed ◽  
Surface Film ◽  
Thin Liquid Film ◽  
Research Centre ◽  
Source Terms ◽  
Thickness Measurements ◽  
Edge Separation ◽  
Fully Coupled

Abstract To create an adequate computational model of oil behaviour in an aeroengine bearing chamber previous work at the Gas Turbine and Transmissions Research Centre (G2TRC) suggests it is necessary to be able to model oil shedding from bearings, breaking up into droplets/ligaments and forming thin and thick films driven by gravity and shear. Our previously published work using Fluent successfully coupled volume of fluid with the Eulerian thin film model (ETFM) and identified the challenges coupling the ETFM with the discrete phase modelling (DPM). For this latter work comparison was made to published experimental and modelling data in which a jet is injected into a duct breaking up into droplets before forming a wall film. In this paper the use of the open-source CFD code OpenFOAM is investigated for this application recognising that such an approach eliminates some of the restrictions in a commercial product. A transient solver for spray particle cloud modelling and thin liquid film transport (sprayParcelFilmFoam) has been developed and incorporated within OpenFOAM. Fully coupled DPM-ETFM is presented, capable of modelling both primary atomization and secondary breakup. In addition two new film sub-models have been implemented for film stripping and edge separation. In order to achieve accurate statistical representation of droplets, modifications to the DPM particle injector code were implemented. CFD results are validated against published high speed imaging and phase Doppler experimental data and in addition there is a comparison to computational results obtained using ANSYS Fluent. The fidelity of both the solver and the novel surface film sub-models are evaluated against average film thickness measurements along the duct centreline. With the inclusion of both film stripping and edge separation, a normalized root mean squared deviation of 5.1 % was achieved when compared to film thickness measurements, improving significantly on the results obtained with Fluent. A comparison with experimental data of particle diameters and velocities downstream of the expansion edge gives good qualitative agreement. Future work is recommended to provide a better formulation for the edge-separated droplet diameters. Analysis of film momentum source terms highlights the necessity for including both the gas and hydrostatic pressure source terms within the film momentum transport equation. This CFD investigation has successfully established a fully coupled two-way DPM-ETFM approach. This work illustrates an advance in bearing chamber modelling capability and has established a necessary foundation for future aeroengine bearing chamber film modelling.

Modeling and Optimization of Rolling Process: A Multi-Objective Approach

2020 ◽  
Vol 19 (02) ◽  
pp. 343-364
Author(s):  
S. Panda ◽  
S. N. Panda
Keyword(s):  
Cold Rolling ◽  
Film Thickness ◽  
Temperature Rise ◽  
High Speed ◽  
Rolling Process ◽  
Response Analysis ◽  
Strip Rolling ◽  
Multi Objective ◽  
Inlet Zone ◽  
Cold Strip Rolling

In a high-speed cold strip rolling process, it is necessary to optimize the process parameters for improved quality in the product. In this study, two separate multi-objective optimization problems for a cold rolling process are formulated. The objectives in one of the cases are minimum isothermal film thickness and film temperature rise in the inlet zone and in another case it is minimum thermal film thickness and film temperature rise in the inlet zone. Particle swarm optimization algorithm has been used for solving the optimization problem. The key input parameters for the cold rolling process are identified and prioritized through the convergence study and the coefficient of variation analysis. A response analysis is performed on the critical input variables. This study assists the process engineer to understand the lubrication in cold strip rolling at high speed and select an appropriate lubricant for a given combination of strip and rolls.

Analysis of Thermal Properties of Super-High Speed Hybrid Journal Bearing Based on ANSYS

2010 ◽  
Vol 118-120 ◽  
pp. 753-757 ◽  
Author(s):  
Shi Chao Xiu ◽  
Shi Qiang Gao ◽  
Zhi Li Sun
Keyword(s):  
Thermal Properties ◽  
Temperature Rise ◽  
High Speed ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Main Shaft ◽  
Temperature Field Distribution ◽  
Shaft System ◽  
The Mathematical Model ◽  
Heat Mechanism

Hybrid journal bearings are used in the high and super high speed cases mainly, such as the super-high speed spindle system. Since the bearing operates under high speed conditions, the excessive temperature rise of the bearing is a major reason to lower the accuracy of the main shaft system and limit the bearings working speed higher, as a result, restrict the bearing applications. In this paper, the thermal properties and the heat mechanism of such bearings are analyzed. The mathematical model of hybrid journal bearing is established to analyze the mechanism of generating heat. In addition, the temperature field distribution for the certain hybrid journal bearing at speed of 10000 rpm is studied by means of software ANSYS considering the heat transfer characters between fluid and solid. An improved measure about temperature rise of hybrid journal bearing is presented.

Evaluation of Pitting Life of Carburized Gears Lubricated by ATF and Traction Oil

2000 ◽  
Author(s):  
Masashi Yamanaka ◽  
Kazuhiko Kishi ◽  
Katsumi Inoue ◽  
Masana Kato ◽  
Tomoya Masuyama ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Surface Temperature ◽  
Fatigue Test ◽  
Temperature Rise ◽  
Fatigue Tests ◽  
Frictional Heat ◽  
Tooth Surface ◽  
Working Fluid ◽  
Traction Coefficient

Abstract This paper presents the result of fatigue tests carried out with an ATF and two types of traction oil. Since the performance of these oils as working fluid is preferred, the performance as a lubricant is inferior. The pitting life is evaluated by the value of D computed by the surface roughness and EHL film thickness. The high traction coefficient causes the tooth surface temperature rise by frictional heat, and then the oil film thickness and pitting life are decreased. To evaluate the performance of these oils as lubricants, the tooth surface temperature at the pitting tests is measured and the EHL film thickness is calculated with it for computing the value of D precisely. All results of fatigue test with three types of oils are examined together and it is found out that they are evaluated by the value of D only. The experimental formula to estimate the pitting life is obtained. This procedure is useful to design the surface gear strength of the automotive ATs and CVTs.

Design of Efficient Turbulent Thrust Bearings

1977 ◽  
Vol 99 (1) ◽  
pp. 113-121
Author(s):  
D. F. Wilcock
Keyword(s):  
High Temperature ◽  
Film Thickness ◽  
Temperature Rise ◽  
Power Loss ◽  
High Speed ◽  
Thrust Bearings ◽  
Higher Power ◽  
Minimum Film Thickness ◽  
Oil Flow ◽  
High Temperature Rise

Turbulence makes high speed conventionally designed bearings operate with higher power loss, high temperature rise, and lower oil flow than predicted. The objective of this paper is to show that the phenomenon of turbulence can be turned to the designer’s and operator’s advantage; and that turbulent thrust bearings can be designed to operate with lower power loss than conventional design would predict, while maintaining the same minimum film thickness and safe temperature rise.

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