Thermal Analysis of Solids at High Peclet Numbers Subjected to Moving Heat Sources

1999 ◽  
Vol 121 (1) ◽  
pp. 182-186 ◽  
Author(s):  
O. Manca ◽  
B. Morrone ◽  
S. Nardini
Keyword(s):  
Thermal Field ◽  
Three Dimensional ◽  
Heat Losses ◽  
Transfer Model ◽  
Heat Sources ◽  
Moving Heat Source ◽  
Motion Direction ◽  
Thermal Fields ◽  
Diffusion Component ◽  
Conductive Thermal Field

A three-dimensional heat transfer model has been developed to obtain the conductive thermal field inside a brick-type solid under a moving heat source with different beam profiles. The problem in quasi-steady state has been approximated by neglecting the axial diffusion component; thus, for Peclet numbers greater than 5, the elliptic differential equation becomes a parabolic one along the motion direction. The dependence of the solution on the radiative and convective heat losses has been highlighted. Thermal fields are strongly dependent on different spot shapes and on the impinging jet; this situation allows control of the parameters involved in the technological process.

Transient Heat Conduction in Solids Irradiated by a Moving Heat Source

2009 ◽  
Vol 283-286 ◽  
pp. 358-363 ◽  
Author(s):  
Nicola Bianco ◽  
Oronzio Manca ◽  
Sergio Nardini ◽  
Salvatore Tamburino
Keyword(s):  
Three Dimensional ◽  
Transient Heat Conduction ◽  
Laser Source ◽  
Comsol Multiphysics ◽  
Work Piece ◽  
Temperature Profiles ◽  
Moving Heat Source ◽  
Gaussian Laser Beam ◽  
Motion Direction ◽  
Thermal Fields

Transient three-dimensional temperature distribution in a solid irradiated by a moving Gaussian laser beam was investigated numerically by means of COMSOL Multiphysics 3.3. The investigated work-piece are simply brick-type solids. A laser source is considered moving with constant velocity along the motion direction. The solid dimension along the motion direction is assumed as semi-infinite while width and thickness are considered finite. Several different grid distributions are tested to ensure that the calculated results are grid independent. Typical parameters involved in the processes for any particular application should be evaluated, in order to optimize the material processing and forecast the solid behavior. The results are presented in terms of temperature profiles and thermal fields are given for some Biot and Peclet numbers.

scholarly journals The Effects of Water Friction Loss Calculation on the Thermal Field of the Canned Motor

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 256 ◽  
Author(s):  
Yiping Lu ◽  
Azeem Mustafa ◽  
Mirza Abdullah Rehan ◽  
Samia Razzaq ◽  
Shoukat Ali ◽  
...  
Keyword(s):  
Thermal Field ◽  
Test Method ◽  
Friction Loss ◽  
Heat Sources ◽  
Thermal Fields ◽  
Flow And Heat Transfer ◽  
Transfer Equations ◽  
Volume Method ◽  
Canned Motor ◽  
Separation Test

The thermal behavior of a canned motor also depends on the losses and the cooling capability, and these losses cause an increase in the temperature of the stator winding. This paper focuses on the modeling and simulation of the thermal fields of the large canned induction motor by different calculation methods of water friction loss. The values of water friction losses are set as heat sources in the corresponding clearance of water at different positions along the duct and are calculated by the analytical method, loss separation test method, and by assuming the values that may be larger than the experimental results and at zero. Based on Finite volume method (FVM), 3D turbulent flow and heat transfer equations of the canned motor are solve numerically to obtain the temperature distributions of different parts of the motor. The analysis results of water friction loss are compared with the measurements, obtained from the total losses using the loss separation method. The results show that the magnitude of water friction loss within various parts of the motor does not affect the position of peak temperature and the tendency of the temperature distribution of windings. This paper is highly significant for the design of cooling structures of electrical machines.

Numerical Analysis on the Temperature Field in Laser-Plasma Hybrid Welding of an Aluminum Alloy

2008 ◽  
Vol 580-582 ◽  
pp. 279-282
Author(s):  
Zhi Ning Li ◽  
Bao Hua Chang ◽  
Dong Du ◽  
Hua Zhang
Keyword(s):  
Heat Transfer ◽  
Aluminum Alloy ◽  
Laser Plasma ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transfer Model ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Plasma Arc ◽  
Simulation Results

A three dimensional heat transfer model on laser-plasma hybrid welding has been proposed, that takes into account the interaction between laser beam and plasma arc. Through FEM computation, the temperature fields were computed and analyzed for an Al-Li alloy during laserplasma hybrid welding with different distances between the two heat sources. The simulation results are in agreement with the experimental results.

Effect of Impinging Jet on Heat Conduction in Workpieces Irradiated by a Moving Heat Source

2011 ◽  
Vol 312-315 ◽  
pp. 924-928 ◽  
Author(s):  
N. Bianco ◽  
Oronzio Manca ◽  
Sergio Nardini ◽  
Salvatore Tamburrino
Keyword(s):  
Radiative Heat ◽  
Three Dimensional ◽  
Impinging Jet ◽  
Laser Source ◽  
Comsol Multiphysics ◽  
Finite Width ◽  
Moving Heat Source ◽  
Temperature Dependent ◽  
Motion Direction ◽  
Biot Numbers

A three dimensional conductive field is analyzed and solved by means of the COMSOL Multiphysics code. The investigated work-pieces are made up of a simple brick-type solid. A laser source with combined donut-Gaussian distributions is considered moving with a constant velocity along motion direction. The solid dimension along the motion direction is assumed to be infinite or semi-infinite, while finite width (2ly) and thickness (s) are considered. Thermal properties are considered temperature dependent and the materials are considered isotropic. Surface heat losses toward the ambient are taken into account. Several convective heat flux values on the upper surface, with corresponding Biot numbers, and Peclet numbers are considered with negligible radiative heat losses.Results are presented in terms of profile temperatures to evaluate the effect of impinging jet.

Effect of Solid Thickness on Transient Heat Conduction in Workpieces Irradiated by a Moving Heat Source

2010 ◽  
Vol 297-301 ◽  
pp. 1445-1450 ◽  
Author(s):  
Nicola Bianco ◽  
Oronzio Manca ◽  
Sergio Nardini ◽  
Salvatore Tamburrino
Keyword(s):  
Three Dimensional ◽  
Transient Heat Conduction ◽  
Surface Heat ◽  
Laser Source ◽  
Comsol Multiphysics ◽  
Finite Width ◽  
Moving Heat Source ◽  
Temperature Dependent ◽  
Motion Direction ◽  
Gaussian Distributions

In this paper a three dimensional conductive field is analyzed and solved by means of the COMSOL Multiphysics code. The investigated work-pieces are made up of a simple brick-type solid. A laser source with combined donut-Gaussian distributions is considered moving with a constant velocity along motion direction. The solid dimension along the motion direction is assumed to be infinite or semi-infinite, while finite width (2ly) and thickness (s) are considered. Thermal properties are considered temperature dependent and the materials are considered isotropic. Surface heat losses toward the ambient are taken into account. Results are presented in terms of profile temperature to evaluate the effect of solid thickness.

Numerical Simulation of Transient Temperature Fields in Solids Irradiated by Moving Gaussian and Donut Sources

2011 ◽  
Vol 312-315 ◽  
pp. 959-964
Author(s):  
Oronzio Manca ◽  
Sergio Nardini ◽  
Daniele Ricci ◽  
Salvatore Tamburrino
Keyword(s):  
Power Distribution ◽  
Three Dimensional ◽  
Axial Direction ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Transfer Model ◽  
Finite Width ◽  
Infinite Length ◽  
Laser Material Processing ◽  
Motion Direction

This work presents a three-dimensional heat transfer model developed for laser material processing with a moving Gaussian and donut heat sources, using Comsol Multhiphysics 3.5 code. The laser beam, having a defined power distribution, strikes the surface of an opaque substrate of semi infinite length but finite width and depth moving with a uniform velocity in the positive axial direction. The solid dimension along the motion direction is assumed to be infinite or semi-infinite, while a finite width and thickness are considered. Thermal properties are considered temperature dependent. Surface heat losses toward the ambient are taken into account. The results are presented in terms of temperature profiles and thermal fields are given for some Biot and material thicknesses at a constant Peclet number.

Effects of High Reynolds Number Impinging Jet on the Heat Conduction in Work-Pieces Irradiated by a Moving Heat Source

2014 ◽  
Vol 354 ◽  
pp. 189-194
Author(s):  
Oronzio Manca ◽  
Sergio Nardini ◽  
D. Ricci ◽  
S. Tamburrino
Keyword(s):  
Three Dimensional ◽  
Impinging Jet ◽  
Reynolds Numbers ◽  
Heat Losses ◽  
Laser Source ◽  
Finite Width ◽  
Temperature Dependent ◽  
Motion Direction ◽  
Commercial Code ◽  
High Reynolds

A three dimensional conductive field is analyzed and solved numerically by means of a commercial code. The investigated work-pieces are made up of a simple brick-type solid. A laser source with combined donut-Gaussian distributions is considered moving with a constant velocity along motion direction. The solid dimension along the motion direction is assumed to be infinite or semi-infinite, while finite width (2ly) and thickness (s) are considered. Thermal properties are considered temperature dependent and the materials are considered isotropic. Surface heat losses toward the ambient are taken into account. Several Reynolds numbers of the impinging jet, Biot and Peclet numbers are considered with negligible radiative heat losses. Results are presented in terms of temperatures field and profile to evaluate the effect of impinging jet.

Effect of Ventilation Systems on Stator Thermal Field of Induction Machines

2013 ◽  
Vol 860-863 ◽  
pp. 1679-1682
Author(s):  
Cong Hui Huang ◽  
Yang Zhang ◽  
Xin Zhen Wu
Keyword(s):  
Physical Model ◽  
Thermal Field ◽  
Three Dimensional ◽  
Induction Machine ◽  
Induction Machines ◽  
Volume Element ◽  
Thermal Fields ◽  
Finite Volume Element ◽  
Coupling Calculation ◽  
Thermal Transmission

A three dimensional physical model for coupling calculation of flow and thermal transmission in induction machine is established in order to research the effect of stator ventilation on the performance of radiating with the method of finite volume element. The thermal fields of different ventilation structures under same basic size and equal total ventilation quantity of the induction machine are calculated and compared numerically. The results indicate that the addition of wind path will reduce the highest temperature in stator and cool the overhang portion remarkably.

scholarly journals A Proof-of-Concept Algorithm for the Retrieval of Total Column Amount of Trace Gases in a Multi-Dimensional Atmosphere

2021 ◽  
Vol 13 (2) ◽  
pp. 270
Author(s):  
Adrian Doicu ◽  
Dmitry S. Efremenko ◽  
Thomas Trautmann
Keyword(s):  
Trace Gases ◽  
Three Dimensional ◽  
Principal Component ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Proof Of Concept ◽  
Discrete Ordinate ◽  
Distribution Method ◽  
Total Column

An algorithm for the retrieval of total column amount of trace gases in a multi-dimensional atmosphere is designed. The algorithm uses (i) certain differential radiance models with internal and external closures as inversion models, (ii) the iteratively regularized Gauss–Newton method as a regularization tool, and (iii) the spherical harmonics discrete ordinate method (SHDOM) as linearized radiative transfer model. For efficiency reasons, SHDOM is equipped with a spectral acceleration approach that combines the correlated k-distribution method with the principal component analysis. The algorithm is used to retrieve the total column amount of nitrogen for two- and three-dimensional cloudy scenes. Although for three-dimensional geometries, the computational time is high, the main concepts of the algorithm are correct and the retrieval results are accurate.

Comparison of the reluctance laminated and solid rotor synchronous machine operating at high temperatures

2019 ◽  
Vol 38 (4) ◽  
pp. 1111-1119 ◽  
Author(s):  
Marcin Lefik ◽  
Krzysztof Komeza ◽  
Ewa Napieralska-Juszczak ◽  
Daniel Roger ◽  
Piotr Andrzej Napieralski
Keyword(s):  
High Speed ◽  
Design Methodology ◽  
Three Dimensional ◽  
Synchronous Machine ◽  
Point Of View ◽  
Heat Sources ◽  
Model Calculations ◽  
Content Type ◽  
Thermal Phenomenon ◽  
Practical Implications

Purpose The purpose of this paper is to present a comparison between reluctance synchronous machine-enabling work at high internal temperature (HT° machine) with laminated and solid rotor. Design/methodology/approach To obtain heat sources for the thermal model, calculations of the electromagnetic field were made using the Opera 3D program including effect of rotation and the resulting eddy current losses. To analyse the thermal phenomenon, the 3D coupled thermal-fluid (CFD) model is used. Findings The presented results show clearly that laminated construction is much better from a point of view of efficiency and temperature. However, solid construction can be interesting for high speed machines due to their mechanical robustness. Research limitations/implications The main problem, despite the use of parallel calculations, is the long calculation time. Practical implications The obtained simulation and experimental results show the possibility of building a machine operating at a much higher ambient temperature than it was previously produced for example in the vicinity of the aircraft turbines. Originality/value The paper presents the application of fully three-dimensional coupled electromagnetic and thermal analysis of new machine constructions designed for elevated temperature.

Sign in / Sign up

Export Citation Format

Share Document