scholarly journals Numerical simulation of temperature field in the vertical Bridgman method crystal growth

10.30544/130 ◽  
2015 ◽  
Vol 21 (1) ◽  
pp. 25-34
Author(s):  
Srdjan Perišić ◽  
Ahmed Ali Awhida ◽  
Vesna Radojević ◽  
Dejan Davidović ◽  
Dejan Trifunović ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Crystal Growth ◽  
Numerical Data ◽  
Sufficient Accuracy ◽  
The Finite Element Method ◽  
Growth Regime ◽  
Vertical Bridgman ◽  
The Mathematical Model

The mathematical model for heat transfer during the Bridgeman crystal growth, using the finite element method and the obtained result аre presented. Some modifications to the method were introduced in order to incorporate the data obtained experimentally. Solving the model enabled comparison of the experimental and numerical data and to obtain sufficient accuracy. The model was used to calculate the temperature gradient in the sample and the calculated gradient was in accordance with the observed crystal growth regime.

scholarly journals The plane-to-cellular-to-dendrite transition of the shape of the crystallization front during the crystallization of Al-Cu alloys

2006 ◽  
Vol 71 (3) ◽  
pp. 303-312
Author(s):  
Vesna Radojevic ◽  
Andreja Valcic ◽  
Slobodanka Nikolic ◽  
Aleksandar Golubovic
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Crystal Growth ◽  
Temperature Gradient ◽  
Crystallization Front ◽  
The Finite Element Method ◽  
Cu Alloys ◽  
Vertical Bridgman

The evolution of the crystallization front from a planar to a dendritic one as a function of the G L/(Rc 0) parameter was investigated during the crystallization of Al-Cu alloys by the vertical Bridgman method. Six series of alloys with different initial compositions of Cu were solidified at different growth rates. A mathematical model for the heat transfer during vertical Bridgmen crystal growth was developed. The model was solved using the finite element method. The temperature gradient in the melt at the beginning of crystal growth was calculated using the obtained model. Discrete stages of the crystallization front were identified in the experiments, as the ratio G L/(Rc 0) decreased.

scholarly journals Transient Behavior of Solar Heated Radiation Receivers for Small Gas Turbine Power Plants

1987 ◽  
Author(s):  
K. Bammert ◽  
J. Johanning ◽  
H. Lange
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Gas Turbine ◽  
Power Plants ◽  
Transient Behavior ◽  
Sufficient Accuracy ◽  
Solar Heating ◽  
Radiation Receiver ◽  
Unsteady Operation ◽  
The Mathematical Model

Solar heating of gas turbine plants is moving back to the focus of current research. The mainly unsteady operation of solar turbine power plants can only be predicted with sufficient accuracy if the transient behavior of the solar radiation receiver is known. Therefore the transient behavior of cavity receivers of different designs is investigated. The mathematical model used to simulate heat transfer and energy storage is illustrated. Computed results for two receivers with different inner lining are compared and evaluated concerning their use in practice.

Numerical Simulation of Heat Transfer and Convection for CaF2 Crystal Growth by Vertical Bridgman Growth Method

2020 ◽  
Vol 55 (3) ◽  
pp. 1900191
Author(s):  
Xiaohui Li ◽  
Dapeng Jiang ◽  
Jingya Wang ◽  
Xiaobo Qian ◽  
Rongrong Liu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Crystal Growth ◽  
Bridgman Growth ◽  
Caf2 Crystal ◽  
Growth Method ◽  
Vertical Bridgman

scholarly journals Numerical modeling of heat flow between three-dimensional regions in contact problems

2018 ◽  
Vol 157 ◽  
pp. 08010
Author(s):  
Tomasz Skrzypczak ◽  
Ewa Węgrzyn-Skrzypczak
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Numerical Modeling ◽  
Three Dimensional ◽  
Contact Problems ◽  
Heat Transfer Process ◽  
Heat Diffusion ◽  
The Finite Element Method ◽  
Three Dimensional Objects ◽  
The Mathematical Model

The method of numerical modeling of heat transfer between three-dimensional objects being in contact is described in the paper. Presented approach is based on the finite element method (FEM) with independent spatial discretization of considered regions. The gap between external surfaces of the interacting objects has variable width and is filled with gas or liquid. The medium in the gap introduces thermal resistance into heat transfer process. The mathematical model of considered problem is based on the equation of heat diffusion supplemented by the appropriate initial and boundary conditions. The deformations of the regions resulting from the thermally dependent changes of their volumes are also included in the model. The results of numerical simulations are presented and discussed.

Systems Actuated by Shape Memory Alloys: Identification and Modeling

2021 ◽  
Vol 1 (2) ◽  
pp. 12-20
Author(s):  
Najmeh Keshtkar ◽  
Johannes Mersch ◽  
Konrad Katzer ◽  
Felix Lohse ◽  
Lars Natkowski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Numerical Simulations ◽  
Shape Memory ◽  
Transfer Equation ◽  
Mechanical Parameters ◽  
Heat Transfer Equation ◽  
The Mathematical Model

This paper presents the identification of thermal and mechanical parameters of shape memory alloys by using the heat transfer equation and a constitutive model. The identified parameters are then used to describe the mathematical model of a fiber-elastomer composite embedded with shape memory alloys. To verify the validity of the obtained equations, numerical simulations of the SMA temperature and composite bending are carried out and compared with the experimental results.

MATHEMATICAL ANALYSIS OF THE ENDEMIC EQUILIBRIUM OF MALARIAHYGIENE MODEL

2021 ◽  
Vol 5 (10) ◽  
Author(s):  
Oluwafemi Temidayo J. ◽  
Azuaba E. ◽  
Lasisi N. O.
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Equilibrium Point ◽  
Reproduction Number ◽  
Endemic Equilibrium ◽  
The Mathematical Model ◽  
Globally Stable ◽  
Well Posed ◽  
The Basic Reproduction Number ◽  
Invariant Principle

In this study, we analyzed the endemic equilibrium point of a malaria-hygiene mathematical model. We prove that the mathematical model is biological and meaningfully well-posed. We also compute the basic reproduction number using the next generation method. Stability analysis of the endemic equilibrium point show that the point is locally stable if reproduction number is greater that unity and globally stable by the Lasalle’s invariant principle. Numerical simulation to show the dynamics of the compartment at various hygiene rate was carried out.

Numerical Simulation of Subsea Cluster Manifold Installation by the Sheave Method

2018 ◽  
Author(s):  
Yu Zhao ◽  
Yingying Wang ◽  
Liwei Li ◽  
Chao Yang ◽  
Yang Du ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
South China Sea ◽  
Deep Sea ◽  
High Reliability ◽  
Two Dimensional ◽  
Complex Environment ◽  
Lumped Mass ◽  
Lumped Mass Method ◽  
The Mathematical Model

The sheave installation method (SIM) is an effective and non-conventional method to solve the installation of subsea equipment in deep water (>1000m), which has been developed to deploy the 175t Roncador Manifold I into 1,885 meters water depth in 2002. With the weight increment of subsea cluster manifold, how to solve its installation with the high reliability in the deep sea is still a great challenge. In this paper, the installation of the 300t subsea cluster manifold using the SIM is studied in the two-dimensional coordinate system. The mathematical model is established and the lumped mass method is used to calculate the hydrodynamic forces of the wireropes. Taking into account the complex environment loads, the numerical simulation of the lowering process is carried out by OrcaFlex. The displacement and vibration of the subsea cluster manifold in the z-axis direction and the effective tension at the top of the wireropes can be gotten, which can provide guidance for the installation of the cluster manifold in the South China Sea.

scholarly journals Population Behavior in the Mathematical Model of the Spread of COVID19 Type SEIRS

2021 ◽  
Vol 6 (2) ◽  
pp. 83-88
Author(s):  
Asmaidi As Med ◽  
Resky Rusnanda
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Everyday Life ◽  
Applied Mathematics ◽  
Living Things ◽  
Simulation Results ◽  
Parameter Values ◽  
The Mathematical Model ◽  
Disease Free

Mathematical modeling utilized to simplify real phenomena that occur in everyday life. Mathematical modeling is popular to modeling the case of the spread of disease in an area, the growth of living things, and social behavior in everyday life and so on. This type of research is included in the study of theoretical and applied mathematics. The research steps carried out include 1) constructing a mathematical model type SEIRS, 2) analysis on the SEIRS type mathematical model by using parameter values for conditions 1and , 3) Numerical simulation to see the behavior of the population in the model, and 4) to conclude the results of the numerical simulation of the SEIRS type mathematical model. The simulation results show that the model stabilized in disease free quilibrium for the condition  and stabilized in endemic equilibrium for the condition .

scholarly journals Numerical simulation of changes in the electric properties of biological tissues under local heating by laser radiation

2021 ◽  
Vol 2090 (1) ◽  
pp. 012049
Author(s):  
N V Kovalenko ◽  
A V Smirnov ◽  
O A Ryabushkin
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Laser Radiation ◽  
Optical Radiation ◽  
Local Heating ◽  
Biological Tissues ◽  
Electric Properties ◽  
Reliable Tool ◽  
The Mathematical Model

Abstract The mathematical model that describes the local heating of biological tissues by optical radiation is introduced. Changes of the electric properties of biological tissues in such process can be used as a reliable tool for analyzing heating and damage degrees of tissues.

scholarly journals Development of condenser mathematical model for research and development of ways to improve its efficiency

2020 ◽  
Vol 18 (4) ◽  
pp. 578-585
Author(s):  
Madina Shavdinova ◽  
Konstantin Aronson ◽  
Nina Borissova
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Water Temperature ◽  
Steam Turbine ◽  
Cooling Water ◽  
Laboratory Research ◽  
Thermal Engineering ◽  
Linear Regression Method ◽  
Cooling Water Temperature ◽  
The Mathematical Model

The condensing unit is one of the most important elements of the steam turbine of a combined heat and power plant. Defects in elements of the condensing unit lead to disturbances in the steam turbine operation, its failures and breakdowns, as well as efficiency losses of the plant. Therefore, the operating personnel need to know the cause of the malfunction and to correct it immediately. There are no diagnostic models of condensers in the Republic of Kazakhstan at the moment. In this regard, a mathematical model of a condenser based on the methodology of Kaluga Turbine Plant (KTP) has been developed. The mathematical model makes it possible to change the input parameters, plot dependency diagrams, and calculate the plant efficiency indicators. The mathematical model of the condenser can be used to research ways for the improvement of the condensing unit efficiency, for diagnostic purposes of the equipment condition, for the energy audit conduction of the plant, and in the training when performing virtual laboratory research. Using static data processing by linear regression method we obtain that the KTP methodology of condenser calculation is fair at cooling water temperature from 20 °C to 24 °C, but at cooling water temperature from 20 °C to 28 °C, the methodology of JSC "All-Russia Thermal Engineering Institute" (JSC "VTI") is used. One of the ways to increase the condenser efficiency has been proposed. It is the heat transfer augmentation with riffling annular grooves on tubes. This method increases the heat transfer coefficient by 2%, reduces the water subcooling of the heating steam by 0.9 °C, and decreases the cooling area by 2%.

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