scholarly journals TWO APPROACHES TO THE COMPUTATION OF ELECTROTHERMAL PROCESSES AT INDUCTION HEATING OF MOVING INGOTS – BY FIELD THEORY AND THERMAL CIRCUIT THEORY

2021 ◽  
Vol 2021 (59) ◽  
pp. 5-10
Author(s):  
A.A. Shcherba ◽  
◽  
A.D. Podoltsev ◽  
I.M. Kucheriava ◽  
V.M. Zolotarev ◽  
...  
Keyword(s):  
Field Theory ◽  
Heat Transfer ◽  
Temperature Distribution ◽  
Induction Heating ◽  
Thermal Field ◽  
Circuit Theory ◽  
Thermal Processes ◽  
Computational Results ◽  
Thermal Circuit ◽  
Good Agreement

The model for the computation of thermal processes in induction heating installations with moving ingots is developed using equivalent thermal circuits. The controlled current sources as additional elements in the model are used to take into account the convective heat transfer along the moving ingot. The model is implemented in the program Matlab/Simulink and makes it possible to determine the temperature distribution along the ingot under steady-state heating conditions. The results are compared with data obtained by the alternative method which is based on the electromagnetic and thermal field theory and realized in the Comsol program. As shown the computational results by two methods concerning the temperature distribution along the ingot are in good agreement. The existing advantages and shortcomings of the used approaches are discussed. Ref. 8, fig. 3, table.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

scholarly journals Temperature distribution of a test specimen with high-speed heat air-flow passing through

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2527-2538 ◽  
Author(s):  
Kai Xiong ◽  
Yunhua Li ◽  
Sujun Dong
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Test Specimen ◽  
High Speed ◽  
Air Flow ◽  
Prediction Method ◽  
Average Temperature ◽  
Hot Air ◽  
Heat Transfer Theory ◽  
Good Agreement

In this paper, a solution method for the temperature distribution of rectangular test specimen with a high-speed heat air-flow passing through is proposed based on the heat transfer theory and numerical calculation, and the feasibility of temperature prediction method is validated. Firstly, the partial differential equations to describe the average temperature in the section of the hot air-flow and the specimen are established and the solving method using MATLAB solver is proposed. Then, based on heat transfer conduction equation and the average temperature, the temperature distribution at different point in each section is calculated. The comparison between numerical computation and experiment shows that two results are in good agreement, which verifies the correctness of the presented prediction method of the temperature distribution of the specimen.

Optimal Perturbation Iteration Method for Solving Nonlinear Heat Transfer Equations

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Sinan Deniz
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Iteration Method ◽  
Numerical Solutions ◽  
Nonlinear Differential Equations ◽  
Optimal Perturbation ◽  
Transfer Equations ◽  
Better Than ◽  
Good Agreement ◽  
Distribution Equation

In this paper, the new optimal perturbation iteration method (OPIM) is introduced and applied for solving nonlinear differential equations arising in heat transfer. The effectiveness of the proposed method will be tested by considering two specific applications: the temperature distribution equation in a thick rectangular fin radiation to free space and cooling of a lumped system with variable specific heat. Comparing different methods shows that the results obtained by optimal perturbation iteration method are very good agreement with the numerical solutions and perform better than the most existing analytic methods.

Thermal-Electric Finite Element Analysis and Experimental Validation of Bipolar Electrosurgical Cautery

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Robert E. Dodde ◽  
Scott F. Miller ◽  
James D. Geiger ◽  
Albert J. Shih
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Finite Element ◽  
Temperature Distribution ◽  
Tissue Temperature ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Temperature Dependent Thermal Conductivity ◽  
Insight Into ◽  
Good Agreement

Cautery is a process to coagulate tissues and seal blood vessels using heat. In this study, finite element modeling (FEM) was performed to analyze temperature distribution in biological tissue subject to a bipolar electrosurgical technique. FEM can provide detailed insight into the tissue heat transfer to reduce the collateral thermal damage and improve the safety of cautery surgical procedures. A coupled thermal-electric FEM module was applied with temperature-dependent electrical and thermal properties for the tissue. Tissue temperature was measured using microthermistors at different locations during the electrosurgical experiments and compared to FEM results with good agreement. The temperature- and compression-dependent electrical conductivity has a significant effect on temperature profiles. In comparison, the temperature-dependent thermal conductivity does not impact heat transfer as much as the temperature-dependent electrical conductivity. Detailed results of temperature distribution were obtained from the model. The FEM results show that the temperature distribution can be changed with different electrode geometries. A flat electrode was modeled that focuses the current density at the midline of the instrument profile resulting in higher peak temperature than that of the grooved electrode (105 versus 96°C).

Experimental Analysis and Numerical Modeling of Microwave Reheating of Cylindrically Shaped Instant Rice

2014 ◽  
Vol 10 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Daming Fan ◽  
Chunxiang Li ◽  
Yi Li ◽  
Wei Chen ◽  
Jianxin Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Internal Temperature ◽  
Microwave Application ◽  
Cooked Rice ◽  
Temperature Distributions ◽  
Rice Samples ◽  
Good Agreement

Abstract The purpose of this study was to develop a numerical model to predict the temperature distribution in cylindrically shaped cooked rice samples during microwave reheating and to give impetus to a uniform microwave-heating design. Cylindrically shaped instant rice was reheated by continuous microwave application, and the sample temperature was measured to determine the internal temperature profile which resulted in a desired uniformity of temperature observed using the non-uniformity temperature evaluation. A finite difference method was used to predict the temperature distribution of the cylindrical rice during microwave reheating and applying Lambert’s law to calculate the microwave power absorption in a large sample of cylindrically shaped instant rice. In order to solve the numerical model of heat transfer, the thermal and dielectric properties of instant rice were measured with respect to temperature. Our results showed that the temperature had a significant effect on the specific heat and dielectric loss of rice, while the thermal conductivity and dielectric constant were unaffected. The numerically predicted temperature distributions were in good agreement with the measured ones of instant rice.

Characteristics of Heat Transfer During Machining With Rotary Tools

2004 ◽  
Vol 126 (2) ◽  
pp. 404-407 ◽  
Author(s):  
H. A. Kishawy and ◽  
A. G. Gerber
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Rotational Speed ◽  
Measured Temperature ◽  
Tool Rotational Speed ◽  
Radial Temperature ◽  
Conservation Of Energy ◽  
Finite Volume Discretization ◽  
Heat Partitioning ◽  
Good Agreement

In this paper a model is developed to analyze heat transfer and temperature distribution resulting during machining with rotary tools. The presented model is based on a finite-volume discretization approach applied to a general conservation of energy statement for the rotary tool and chip during machining. The tool rotational speed is modeled and its effect on the heat partitioning between the tool and the chip is investigated. The model is also used to examine the influence of tool speed on the radial temperature distribution on the tool rake face. A comparison between the predicted and previously measured temperature data shows good agreement. In general the results show that the tool-chip partitioning is influenced dramatically by increasing the tool rotational speed at low to moderate levels of tool speed. Also, there is an optimum tool rotational speed at which further increase in the tool rotational speed increases the average tool temperature.

Analysis of Heat Transfer by Natural Convection Across Vertical Fluid Layers

1977 ◽  
Vol 99 (2) ◽  
pp. 287-293 ◽  
Author(s):  
G. D. Raithby ◽  
K. G. T. Hollands ◽  
T. E. Unny
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Average Nusselt Number ◽  
Vertical Temperature ◽  
The Core ◽  
Aspect Ratios ◽  
Fluid Layers ◽  
Transfer Equations ◽  
Vertical Temperature Distribution ◽  
Good Agreement

An analysis is presented which predicts the heat transfer across fluid layers bounded laterally by vertical isothermal surface and adiabatic surfaces on the top and bottom. The vertical temperature distribution in the core of the cavity is also predicted. Extensive comparisons of average Nusselt number and temperature distribution are made with experimental data for aspect ratios greater than 5. Good agreement between analysis and experiment is found. The heat-transfer equations for vertical layers are generalized to include layers which are tilted up to 20° from the vertical, making the results useful for the design of solar collectors.

scholarly journals NUMERICAL SIMULATION OF TEMPERATURE DISTRIBUTION ON METAL CASTING IN VERTICAL SOLIDIFICATION

2018 ◽  
Vol 17 (2) ◽  
pp. 80
Author(s):  
G. M. Stieven ◽  
D. R. Soares ◽  
E. P. Oliveira ◽  
E. F. Lins
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Numerical Technique ◽  
Heat Transfer Process ◽  
Temperature History ◽  
Energy Liberation ◽  
Vertical Solidification ◽  
History Of ◽  
Two Phases ◽  
Good Agreement

The metals and alloys solidification can be defined as a transient heat transfer process. A liquid/solid transformation is followed by thermal energy liberation, with a movable boundary separating two phases with different thermophysical properties. The solidification is of great interest to mechanical and chemical engineers. It is a non-linear transient phenomenon, where heat transfer between the casting and the mold plays a important role. This paper aims to propose a study of heat flow from the casting to the mold using a numerical technique to compute the temperature history of all points inside the casting. The cooling process consists of water-cooled mold with heat being extracted only from the bottom, resulting in unidirectional vertical solidification. The ANSYS software was used to obtain the temperature distribution in the casting. Good agreement was obtained when the simulation results were compared with the experimental data.

scholarly journals Mathematical modeling the thermal processes during cassette crystallization of chalcogenides

2020 ◽  
Vol 22 (3) ◽  
pp. 179-189
Author(s):  
A. I. Prostomolotov ◽  
N. A. Verezub
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Thermal Field ◽  
Crystallization Front ◽  
Transfer Model ◽  
Thermal Processes ◽  
Directed Crystallization ◽  
Conductive Heat ◽  
Bottom Part ◽  
Hot Zone

An original modification of the directed crystallization method is considered as a multi-cassette process, which has comparative simplicity and high productivity. The basis of this research was domestic patents and technological research carried out at the National University of Science and Technology MISIS. As a result, mathematical models of the multi-cassette method were developed that allow both a three-dimensional radiative — conductive analysis of thermal processes in the entire volume of the hot zone and a two-dimensional analysis of convective — conductive heat transfer in a separate cassette. The parametric calculations carried out on their basis were aimed to the identifying an influence of locations and sizes of the hot zone components to a thermal field in the cassette unit; the establishing an influence of vertical heat supply equability to the cassette unit and an influence of heating power decrease during the plate crystallization, as well as to the determining an influence of small cassette design distortions and violation of cooling uniformity in its bottom part on the occurrence of convection and asymmetrical thermal field. By means of the conductive-radiative heat transfer model for the entire hot zone there were carried out parametric calculations and it was analyzed an influence of hot zone components (their locations and temperatures) on the heat exchange conditions at the cassette unit boundaries. By means of the conductive-convective model for a cassette it was determined that the boundary thermal conditions asymmetry, as well as an unstable vertical temperature gradient, result in the convective vortices and a significant deviation of the crystallization front from a flat shape. The calculations with using the convective mass transfer model showed that an increase of the crystallization rate by an order significantly increases a tellurium flux into the crystal, thereby substantially changing a melt composition near crystallization front and, thus, being a potential cause of dendritic growth. The reliability of the calculation results was checked on a number of tests, in which the influence of heat and mass transfer on the crystallization front shape was analyzed at cassette cooling rates corresponding to the growth processes of bismuth telluride polycrystals.

Numerical Study on Thermal Field in Concrete with Cooling Pipe Based on the Coupling Method

2011 ◽  
Vol 94-96 ◽  
pp. 388-392 ◽  
Author(s):  
Yu Lin Lu ◽  
Tao Lu ◽  
Li Wang ◽  
Zhen Yu Wang ◽  
Pei Pei Zhao
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Thermal Field ◽  
Numerical Study ◽  
Thermal Characteristics ◽  
Nusselt Numbers ◽  
Cooling Pipe ◽  
The Mean ◽  
Transfer Method ◽  
Structure Engineering

A finite element method was developed to reveal the thermal characteristics of concrete with a cooling pipe, and the influence of cooling pipe on thermal field was calculated by the coupled fluid flow and solid heat transfer method. Temperature distribution along the pipeline was calculated and the mean Nusselt numbers on each section in the cooling pipe also were obtained. Numerical results show that the flow field and the temperature distribution were very complexly and the heat transfer was severely attenuated in the bend position, the outboard temperature of pipe was higher than the inboard temperature. In addition, in order to study the effect of the cooling pipe on thermal distribution, the temperature of different positions at the hydration time were compared with the no cooling results. The present results could be helpful to predict the temperature cracks in structure engineering.

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