Study on the Thermal Contact Zone in the Surface Grinding

2011 ◽  
Vol 188 ◽  
pp. 523-528
Author(s):  
Chong Lue Hua ◽  
Gui Cheng Wang ◽  
Hong Jie Pei ◽  
Gang Liu
Keyword(s):  
Heat Flux ◽  
Temperature Field ◽  
Thermal Contact ◽  
Heat Fluxes ◽  
Grinding Temperature ◽  
The Finite Element Method ◽  
Temperature Dependent ◽  
Convection Model ◽  
Temperature Dependent Properties ◽  
Circular Heat

The present study aims to investigate the temperature field by using the different heat fluxes, such as rectangle heat flux, triangular heat flux, inclined triangular heat flux, circular heat flux. To obtain a reliable figure of temperature field induced by grinding, temperature-dependent properties of work materials were taken into account and a convection model with an effective cooling factor was introduced. A thorough analysis using the finite element method showed that predictions were very agreed with the results of the experiment. Finally, the present paper showed that the contact angle must be taken into account in future models.

The Temperature Distribution Within a Sphere Placed in a Directed Uniform Heat Flux and Allowed to Radiatively Cool

1985 ◽  
Vol 107 (1) ◽  
pp. 28-32 ◽  
Author(s):  
D. Duffy
Keyword(s):  
Heat Flux ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Analytic Solution ◽  
Blackbody Radiation ◽  
Heat Fluxes ◽  
Uniform Heat Flux ◽  
Transform Methods ◽  
Uniform Heat ◽  
Large Heat

The temperature field within a sphere is found when the sphere is heated by a directed heat flux and cooled by blackbody radiation. For small heat fluxes, the analytic solution is obtained by transform methods. For large heat fluxes, the solution is computed numerically.

Temperature Fields Generated by a Circular Heat Source: Solution of a Composite Solid of Two Different Isotropic Semi-Infinite Media

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Michael Emanuel ◽  
Avi Emanuel
Keyword(s):  
Heat Source ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Integral Form ◽  
Heat Fluxes ◽  
Inverse Laplace Transform ◽  
Temperature Fields ◽  
Circular Heat ◽  
Composite Solid ◽  
Infinite Media

Abstract The problem of a three-dimensional (3D) heat flow from a circular heat source (CHS) embedded inside a composite solid of two isotropic but different semi-infinite media is solved for the first time in this paper. This CHS asymmetrical measurement setup is useful when two identical samples are not available for measurement. Two different time-dependent temperature fields are derived for the composite semi-infinite media, as well as their corresponding heat fluxes. The derivation of the 3D solution uses first principles with basic assumptions and employs the Hankel and Laplace transforms. The Laplace inversion theorem is used to find the inverse Laplace transform of the temperature functions, since no tabulated inverse transform functions are available for this case. The solution is exact with no approximations and is given in an integral form, which can easily be evaluated numerically. This solution is a generic one and can be applied to more complex asymmetrical setups, such as the case involving thermal contact resistances.

The Penny-Shaped Interface Crack With Heat Flow, Part 2: Imperfect Contact

1983 ◽  
Vol 50 (4a) ◽  
pp. 770-776 ◽  
Author(s):  
J. R. Barber ◽  
Maria Comninou
Keyword(s):  
Heat Flux ◽  
Thermal Contact ◽  
Closed Form Solution ◽  
Integral Equation Method ◽  
Form Solution ◽  
Heat Fluxes ◽  
Crack Face ◽  
Imperfect Contact ◽  
Penny Shaped Crack ◽  
Shaped Crack

The penny-shaped crack with heat flux is investigated for the case in which the heat flux is into the material with the lower distortivity. A harmonic potential function representation is used to reduce the problem to a boundary value problem which is solved by an integral equation method. If a sufficiently high tensile traction is applied, a solution is obtained involving a central circle of separation and surrounding annuli of imperfect and perfect thermal contact. For lower tractions, or higher heat fluxes, the crack closes completely and a closed-form solution is obtained in which the division of the crack face into imperfect and perfect contact regions is unaffected by further changes in heat flux or traction. Multiple solutions are obtained in an intermediate range.

A Fractional-Order Generalized Thermoelastic Problem of a Bilayer Piezoelectric Plate for Vibration Control

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Yeshou Xu ◽  
Zhao-Dong Xu ◽  
Tianhu He ◽  
Jinxiang Chen ◽  
Chao Xu
Keyword(s):  
Contact Resistance ◽  
Vibration Control ◽  
Fractional Order ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Elastic Behavior ◽  
Temperature Dependent ◽  
Riemann Sum ◽  
Thermoelastic Plate ◽  
Temperature Dependent Properties

Multilayered piezoelectric structures have special applications for vibration control, and they often serve in a thermoelastic coupling environment. In this work, the fractional-order generalized thermoelasticity theory is used to investigate the dynamic thermal and elastic behavior of a bilayer piezoelectric–thermoelastic plate with temperature-dependent properties. The thermal contact resistance is implemented to describe the interfacial thermal wave propagation. The governing equations for the bilayer piezoelectric–thermoelastic plate with temperature-dependent properties are formulated and then solved by means of Laplace transformation and Riemann-sum approximation. The distributions of the nondimensional temperature, displacement, and stress are obtained and illustrated graphically. According to the numerical results, the effects of the thermal contact resistance, the ratio of the material properties between different layers, the temperature-dependent properties, and the fractional-order parameters on the distributions of the considered quantities are revealed in different cases and some remarkable conclusions are obtained. The investigation helps gain insights into the optimal design of actuators, sensors, which are made of piezoelectric materials.

scholarly journals Thermal Measurement of Harsh Environments Using Indirect Acoustic Pyrometry

2007 ◽  
Author(s):  
P. L. Schmidt ◽  
D. G. Walker ◽  
D. E. Yuhas ◽  
M. J. Mutton
Keyword(s):  
Heat Flux ◽  
Heat Conduction Problem ◽  
Time Of Flight ◽  
Measurement Data ◽  
Ultrasonic Pulse ◽  
Inverse Heat Conduction Problem ◽  
Heat Fluxes ◽  
Estimation Methods ◽  
Inverse Heat Conduction ◽  
Temperature Dependent

The inversion of a composite governing equation for the estimation of a boundary heat flux from ultrasonic pulse data is presented. The time of flight of the ultrasonic pulse is temperature dependent and can be used to predict the boundary heat flux. Sensitivities of the approach are examined, results from fabricated data are presented, and example solutions are provided with actual ultrasonic temperature measurement data. The results indicate that compared to the canonical inverse heat conduction problem, the additional step of resolving the time-of-flight data to temperature degrades the sensitivities. Nevertheless, sampling the entire temperature distribution and enhances the results. This method of using ultrasonic pulses to remotely determine heat fluxes is comparable in terms of accuracy to more common heat flux estimation methods.

The Modeling of Constant/Variable Solar Heat Flux Into a Porous Coil With Concentrator

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Sayyed Aboozar Fanaee ◽  
Mojtaba Rezapour
Keyword(s):  
Heat Flux ◽  
Heat Fluxes ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Solar Heat ◽  
Clear Sky ◽  
Alumina Nanofluid ◽  
Solar Heat Flux ◽  
The City ◽  
Acceptable Agreement

In this paper, thermal-fluid modeling of nonporous/porous thermal coil filled by alumina nanofluid is discussed considering constant/variable solar heat fluxes. The fluxes are calculated for a parabolic concentrator at the solar paths for the city with a longitude of 59.20 deg and latitude of 32.87 deg in the clear sky at spring season. The governing equations are included as continuity, momentum, and energy conservations with considering variable solar flux by shadow effects of the coil on the parabolic concentrator. The numerical model is based on the finite element method by LU algorithm using the mumps solver. The results show that, in a porous medium, that the normalized temperature of the presented model has an acceptable agreement with experimental data with maximum errors of 3%. The existence of porosity significantly increases heat transfer parameters that improve transferred solar heat from the wall of the coil to nanofluid. The variable solar heat flux increases the temperature in the length of the coil rather than constant heat fluxes because of increasing exchanged heat to nanofluid.

scholarly journals Reduction of Thermographic Phosphors Data to Heat Rates

2004 ◽  
Author(s):  
P. R. Crim ◽  
D. G. Walker ◽  
S. W. Allison ◽  
S. Goedeke
Keyword(s):  
Heat Flux ◽  
Heating Rate ◽  
Heat Fluxes ◽  
Single Shot ◽  
Temperature Dependent ◽  
Thermographic Phosphors ◽  
Free Parameters ◽  
A New Technique ◽  
Intensity Decay

Thermographic phosphors have emerged as a new technique for measuring heat fluxes, which relies on the temperature dependent intensity decay of thermographic phosphors. However, instead of reducing the intensity data to temperatures, heating rate is estimated. It has been shown that the heating rate can provide significantly better heat flux estimates than temperature measurements. Because the technique is new, little is known about the quality of heating rate estimates. Further, the heating rate estimation depends on the introduction of additional free parameters, which increases the uncertainty of the estimates. The analysis presented here indicates that sample rates must be one to two orders of magnitude greater than the frequency at which the heat flux must be known. Also, the sensitivity of the intensity to higher-order derivatives is small suggesting that derivatives beyond the heating rate are not accessible with single-shot data.

Flexural Characteristics of a Cantilever Plate Subjected to Heating at Fixed End

2009 ◽  
Vol 25 (1) ◽  
pp. 1-8 ◽  
Author(s):  
I. T. Alzaharnah
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Time Shift ◽  
Cantilever Plate ◽  
The Finite Element Method ◽  
Temperature Dependent ◽  
Impulsive Load ◽  
Excitation Force ◽  
Temperature Dependent Properties ◽  
Fixed End

AbstractThe flexural characteristic of a cantilever plate, which is heated from a fixed end, is considered and the effects of heat transfer on the plate are examined. The plate is heated with a temperature source while an excitation force is applied at the free end. Size of heat source is varied and temperature dependent properties of the plate are accommodated in the simulations. The finite element method (FEM) is adopted to determine the temperature field in the plate and flexural characteristics due to the applied impulsive load. It is found that the flexural characteristics of the plate change notably with the size of the heat source located at the fixed end of the plate. In this case, increasing the size of the heat source results in the enhancement of the amplitude and time shift in the flexural motion of the plate due to the heating and noheating situations.

A variable property heat transfer model for predicting soil temperature profiles during simulated wildland fire conditions

2008 ◽  
Vol 17 (2) ◽  
pp. 205 ◽  
Author(s):  
Ebenezer K. Enninful ◽  
David A. Torvi
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Wildland Fire ◽  
Heat Fluxes ◽  
Transfer Model ◽  
Temperature Dependent ◽  
Heat Penetration ◽  
Experimental Values ◽  
Temperature Dependent Properties ◽  
Plant Shoots

A numerical model of heat transfer in dry soil was developed to predict temperatures and depth of lethal heat penetration during cone calorimeter tests used to simulate wildland fire exposures. The model was used to compare predictions made using constant and temperature-dependent thermal properties with experimental results for samples of dry sand exposed to heat fluxes of 25, 50 and 75 kW m–2. Depths of lethal heat penetration predicted using temperature-dependent properties were within 2 to 10% of the values determined using measured temperatures, while predictions made using constant properties were within 10 to 21% of the experimental values. In both cases, predictions made by the model were within the 1-cm accuracy with which the depth of seeds and plant shoots in the soil can be determined in practice. The model generally over-predicted the depth of lethal heat penetration in dry or moist soil when temperature-dependent properties were used, and over-predicted the depth of lethal heat penetration in soils with a moisture content of greater than 10% if constant thermal properties were used.

Thermal Stress Simulation of the Surface Grinding

2011 ◽  
Vol 383-390 ◽  
pp. 2211-2215
Author(s):  
Chong Lue Hua ◽  
Gui Cheng Wang ◽  
Hong Jie Pei ◽  
Gang Liu
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Surface Grinding ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Temperature Dependent ◽  
Finite Element Procedure ◽  
Temperature Dependent Properties ◽  
Stress Simulation

Thermal stresses of grinding plays an important role on the fatigue and wear resistance of the component. A comprehensive analysis of thermal stress induced by surface grinding has been conducted with aid of the finite element method. To obtain a reliable figure of thermal stress induced by grinding, temperature-dependent properties of workpiece materials were taken into account. The developed finite element procedure has also been applied to calculate the surface and sub-surface thermal stress induced by moving source of triangular heat when convection and radiation is occurred over the whole work. Based on an analysis of the effects of wheel velocity on the thermal stress distributions in an elastic-plastic solid, some important conclusions were given.

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