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Revista Facultad de Ingeniería - Universidad de Tarapacá

On-line version ISSN 0718-1337

Rev. Fac. Ing. - Univ. Tarapacá vol.14 no.1 Arica Apr. 2006

http://dx.doi.org/10.4067/S0718-13372006000100003 

 

Rev. Fac. Ing. - Univ. Tarapacá, vol. 14 No. 1, 2006, pp. 16-25

Alloy Aluminum Solidification in Square Section

Solidificación de Aleación de Aluminio en Cavidad Cuadrada

Carlos Hernán Salinas Lira1

1 Departamento de Ingeniería Mecánica – Universidad del Bío-Bío Av. Collao Nº 1202, Casilla 5-C, Concepción-Chile, CP: 4081112 casali@ubiobio.cl, fono: (56) (41) 731455/731499


Resumen

El objetivo del presente trabajo es desarrollar un modelo numérico para analizar el proceso de solidificación de metales considerando el fenómeno de convección natural en una aleación de aluminio en cavidad cuadrada. El medio físico es modelado como siendo fluido Newtoniano incompresible con propiedades térmicas isotrópicas donde el calor es transferido por conducción y convección incluidos los fenómenos térmicos de cambio de fase. Esto último es modelado por una adaptación del Modelo de Entalpía, basado en una función de sólido la cual libera el calor latente de acuerdo con la fracción de partículas de sólido generada. El modelo matemático contempla un sistema de ecuaciones diferenciales parciales no lineares de segundo orden: Momentum, continuidad, transferencia de calor y un conjunto de expresiones auxiliares que permiten cerrar el sistema y aplicar condiciones en contorno e interfaces. El modelo numérico es basado en el Método de Volúmenes Finitos, descrito en coordenadas curvilíneas y con esquema SIMPLER para acoplar presiones y velocidades. La estrategia de estudio comprende la simulación Bidimensional de aleación de aluminio (solidificación no isotérmica) en una cavidad cuadrada y un caso donde la conductividad del molde es considerada. Resultados transitorios son mostrados en la forma de líneas de corriente y isotermas comparados con datos de la literatura.

Palabras clave: Solidificación, convección, aluminio, cambio de fase, método de volúmenes finitos. 


ABSTRACT

The objective of the present work is to develop a numerical model to analyze the melting solidification process considering the natural convection phenomena to alloy aluminum in a square section. Physical medium is taken as incompressible Newtonian fluid with isotropy thermal properties where the heat is transferred by conduction and convection, included de thermal phase change phenomenon. The last one is modeled by the improvement procedure, called Enthalpy Model, based on the fraction solid function which liberates the latent heat according to fraction of solid particles generated using as parameter of the temperature level. The mathematical model is based on a non-linear second order differential partial equation system: Momentum, continuity, heat transfer equations and a set of auxiliary expressions with the purpose of equation system closure y applied the boundary and interface condition. The numerical model is based on Volume Finite Method in body fitted coordinates with a SIMPLER scheme to join pressure and velocities. The strategy study allows the two-dimensional solidification of alloy aluminum (Non-Isothermal Solidification) in square section and a case where de conductive effects of mould are considered. Unsteady steady results are showed in the way of streamlines and isotherms compared with available data.

Keywords: Solidification, Convection, Alloy Aluminum, Phase Change, Finite Volumes Method.



ACKNOWLEDGMENT

Financial support for this study provided by Conicyt and Universidad del Bío-Bío through grant FONDECYT N° 1030209 and FPI Nº 0152112 respectively, is greatly appreciated.



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Recibido el 9 de mayo de 2005, aceptado el 6 de diciembre de 2005