Numerical simulation of heat transfer during the solidification of pure iron in sand and mullite molds

Abstract

Many complex phenomena favoring the solidification of metal that occur during the casting process, such as cast metal flow, thermal gradient and heat transfer between the cast metal and the mold. The grain size and mechanical properties of cast metal are defined by both these phenomena, and by the geometrical characteristics and thermo-physical properties of the metal and the mold. Heat loss from the mold to the environment through convection can also affect the mechanical properties of cast metal. In this study reported, two-dimensional numerical simulations were made of pure iron solidification in industrial AI 50/60 AFS greensand and mullite molds, using the finite element technique and the ANSYS software program. For this purpose, the iron's thermo-physical properties were considered dependent with temperature, while for sand and mullite these properties were considered constant, and the convection phenomenon was also considered on the mold's external surface. Metallurgical characteristics, such as the attack zone in the feed head and hot top were not taken into account in this study, since they are irrelevant the behavior of heat transfer of the metal to the mold. Owing to the iron's temperature-dependent thermo-physical properties, this type of problem is of nonlinear characteristic. The results of the heat transfer are shown in 2D, as well as, the thermal flux, the thermal gradient and the convergence curves that control the feasibility of the Newton-Raphson algorithm calculation process. The cooling curves at various points of the solidified specimen, and the heating and cooling curves in the mold were also shown. These results were considered relevant

Strategies for the Numerical Modelling of Regenerative Pre-heating Systems for Recycled Glass Raw Material

“…(14), and the heat entering from the lower and upper base of the box; the heat dispersed in the environment is clearly a loss, Eq. (15).…”

“…The gases flowing from the regenerative chamber exit still have, in fact, a considerable amount of energy, with temperatures around 450 C. Since the amount of recycled material inside the glass furnace has become more consistent, the exhaust gases downstream of the regenerative chamber could be further exploited to pre-heat the recycled glass raw material. Similar systems for the pre-heating of raw materials exist in various industrial sectors and have been patented [10][11][12], such as in steel making [13,14] in foundries [15] or for cements [16]. Preheating systems for the glass raw material have already been developed, however there are few numerical models able to model the size of the scrap material and provide an adequate parametric analysis for the design of a pre-heating system.…”

Analisa Proses Perpindahan Panas pada Pengecoran Paduan Al-12%Si dengan Metode Elemen Hingga

“…Software yang berbasis metode elemen hingga dapat meneliti fenomena yang ada selama pengecoran. Seperti Pariona dkk yang meneliti tentang simulasi numerik perpindahan panas selama solidifikasi dari besi murni dengan cetakan berbahan pasir serta berbahan mullite [4]. Kemudian Sunanda dkk yang melakukan penelitian tentang analisa desain dari pengecoran besi murni dengan bahan cetakan yang berbeda yaitu cetakan berbahan pasir silika, berbahan mullite dan cetakan berbahan komposit pasir silika dengan mullite [1].…”

Modelling Phase Change in a 3D Thermal Transient Analysis

“…With the incorporation of Enthalpy (material non-linearity) and thermal contact conductance (contact non-linearity), the transient analysis becomes a non-linear one. The Newton-Raphson method of iteration is employed using the sparse solver to obtain converged results at every sub-step [43]. A summary of the time stepping regime is detailed in Table 4.…”