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Showing 10 results for Modeling

Choo R.t.c., Toguri J.m.,
Volume 1, Issue 1 (3-2004)
Abstract

A two dimensional mathematical model has been developed for describing the temperature, flow, and electric fields in the are column of the Gas Metal Arc Welding (GMAW) of aluminum in argon shielding gas using axisymmetric Navier-Stokes, Maxwell, and differential thermal energy equations. The predicted results are most sensitive to the cathode spot radius and an optimum cathode spot radius exists on the basis of the minimum arc power consumption. The consumable electrode shape change due to droplet detachment is simulated in a quasi-steady manner using different electrode diameters. The change in electric field profile with different electrodes gives rise to large changes in flow conditions. This flow perturbation plus the non-uniform and transient J*B force field are suspected to enhance the recoil experience by the droplet on detachment, thus leading to violent and chaotic metal transfer in GMAW.
Yahosseini M.r.s., Simchi A., Varahram N., Davami P.,
Volume 2, Issue 1 (3-2005)
Abstract

In the present work, a model was proposed to predict the thermal history during rapid solidification (RS) of metal droplets in the gas atomization process. The classical theory of heterogeneous nucleation was based on Newtonian heat flow and enthalpy method. Solving the governing numerical equations by the finite difference method (FDM) gave up the opportunity of analyzing the temperature-time history of the droplets during cooling in the RS process. Here, cooling in the liquid state, nucleation and recalescence, segregated solidification, eutectic solidification and cooling in the solid state were considered. To verify the model, the gas atomization of Al-4.5% Cu alloy was studied and the results were compared with the Shukla's model [1]. Convincing agreement was obtained between the predicted undercoolings and the experimental results reported previously.
Babaei R., Shahinfar S., Homayonifar P., Dadashzadeh M., Davami P.,
Volume 3, Issue 3 (12-2006)
Abstract

In the present study a Finite Difference Method has been developed to model the transient incompressible turbulent free surface fluid flow. A single fluid has been selected for modeling of mold filling and The SOLA VOF 3D technique was modified to increase the accuracy of simulation of filling phenomena for shape castings. For modeling the turbulence phenomena k-e standard model was used. In order to achieve an accurate model, solving domain was discrete to three regions includes: laminar sub layer, boundary layer and internal region. This model was applied to experimental models such as a driven cavity, Campbell benchmark [1] and top filled cavity. The results show that the suggested model yield favorable predictions of turbulence flow and have a good consistency in comparing with experimental results.
A. H. Emami, M. Sh. Bafghi, J. Vahdati Khaki, A. Zakeri,
Volume 6, Issue 2 (6-2009)
Abstract

Abstract:

the changes of BET surface area of a mineral substance during intensive grinding process. Validity of the proposed

model was tested by the experiments performed using a natural chalcopyrite mineral as well as the published data. It

was shown that the model can predict the experimental results with a very good accuracy and can be used to predict

what may happen under the similar experimental conditions.

Based on experimental observations, a model has been developed to describe the effect of grinding time on

M. Adeli, M. Shekari, S. H. Seyedein, M. R. Aboutalebi,
Volume 7, Issue 2 (6-2010)
Abstract

Combustion synthesis is a special thermophysico-chemical process applied for production of intermetallic compounds. In the present work, a reaction–diffusion numerical model was developed to analyze the combustion synthesis of aluminide intermetallics by self-propagating high-temperature synthesis process. In order to verify the reliability of the numerical model, an experimental setup was designed and used to perform the combustion synthesis of nickel and titanium aluminides. The developed model was further used to determine the temperature history of a powder mixture compact during self-propagating high-temperature synthesis. The effect of compact relative density on combustion temperature and wave propagation velocity was also studied.


A. Jafaria, S. H. Seyedeina, M. R. Aboutalebia, D. G. Eskinb, L. Katgermanb,
Volume 7, Issue 3 (8-2010)
Abstract

ABSTRACT Macrosegregation has been received high attention in the solidification modeling studies. In the present work, a numerical model was developed to predict the macrosegregation during the DC Casting of an Al-4.5wt%Cu billet. The mathematical model developed in this study consists of mass, momentum, energy and species conservation equations for a two-phase mixture of liquid and solid in an axisymmetric coordinates. The solution methodology is based on a standard Finite Volume Method. A new scheme called Semi-Implicit Method for Thermodynamically-Linked Equations (SIMTLE) was employed to link energy and species equations with phase diagram of the alloying system. The model was tested by experimental data extracted from an industrial scale DC caster and a relatively good agreement was obtained. It was concluded that a proper macrosegregation model needs two key features: a precise flow description in the two-phase regions and a capable efficient numerical scheme
S. Ghafurian, S. H. Seyedein, M. R. Aboutalebi, M. Reza Afshar,
Volume 8, Issue 3 (9-2011)
Abstract

Abstract: Microwave processing is one of the novel methods for combustion synthesis of intermetallic compounds and
composites. This method brings about a lot of opportunities for processing of uniquely characterized materials. In this
study, the combustion synthesis of TiAl/Al2O3 composite via microwave heating has been investigated by the
development of a heat transfer model including a microwave heating source term. The model was tested and verified
by experiments available in the literature. Parametric studies were carried out by the model to evaluate the effects of
such parameters as input power, sample aspect ratio, and porosity on the rate of process. The results showed that
higher input powers and sample volumes, as well as the use of bigger susceptors made the reaction enhanced. It was
also shown that a decrease in the porosity and aspect ratio of sample leads to the enhancement of the process.
A. Azizi, S. Z. Shafaei, M. Noaparast, M. Karamoozian,
Volume 10, Issue 4 (12-2013)
Abstract

This paper was aimed to address the modeling and optimization of factors affecting the corrosive wear of low alloy and high carbon chromium steel balls. Response surface methodology, central composite design (CCD) was employed to assess the main and interactive effects of the parameters and also to model and minimize the corrosive wear of the steels. The second-order polynomial regression model was proposed for relationship between the corrosion rates and relevant investigated parameters. Model fitted to results indicated that the linear effects of all of factors, interactive effect of pH and grinding time and the quadratic effects of pH and balls charge weight, were statistically significant in corrosive wear of low alloy steel balls. The significant parameters in the corrosive wear of high carbon chromium steel balls were the linear effects of all factors, the interactions effect of solid concentration, mill speed, mill throughout, grinding time, and the quadratic effects of pH and solid content. Also, the results showed that within the range of parameters studied, the corrosion rate of 78.38 and 40.76 could be obtained for low alloy and high carbon chromium steel balls, respectively.
V. Lykhoshva, A. Tymoshenko, L. Mosentsova, V. Savin, D. Schitz,
Volume 15, Issue 1 (3-2018)
Abstract

This article studies the particle temperature distribution depending on the laser radiation power and the particle’s trajectory and velocity. The uneven heating of particles moving in the laser radiation field is identified. The regimes of laser heating without melting, with partial melting, and with complete particle melting are considered.

M. Azarbarmas,
Volume 17, Issue 4 (12-2020)
Abstract

Mechanical properties of metals are substantially dependent on the microstructure, which can be controlled by thermo-mechanical parameters such as the temperature, strain and strain rate. Hence, understanding the microstructural evolution of alloys during the hot deformation is crucial for engineering the metal forming processes. The main objective of this work is to present an overview of Cellular Automaton (CA) modeling for predicting the microstructure of alloys during the dynamic recrystallization (DRX) phenomenon. In this review paper, first, overall descriptions about the DRX phenomenon and CA modeling were presented. Then, the CA modeling procedure was compared with similar methods. Meanwhile, related studies in the field of the DRX simulation by using the CA modeling were evaluated. Four main stages of the model were analyzed in terms of the “nucleation”, “growth”, “topological changes” and “texture evaluation” steps. Most important limitations including the calibration sensitivity, limitations in continuous DRX modeling, ignoring microstructural effects on the deformation behavior, limited applications and database as well as repeated results were discussed and then objective suggestions for the further development were provided. Finally, future prospects in CA modeling of DRX were presented in the last section.
 

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