Finite-Element Investigations Into the General Energy Equation (Solidification, Casting(S), Phase-Change).

The finite-element simulation of heat transfer and metal-casting solidification is discussed. New techniques of latent-heat representation, analysis of surface fluxes throughout the finite-element domain, and specific metal casting solidification simulations are presented and analyzed. The work is performed by a two- and three-dimensional finite-element simulator written in FORTRAN 77 and installed on an Apollo DN660 super micro-computer, containing 256M of virtual memory. The simulator was written exclusively for this research and models the general problem of steady-state or transient energy-transfer with non-linear material properties, phase change, and imposed bulk-flow velocity fields. The simulator contains 52 routines and 5245 lines of source code. Two-dimensional Cartesian and cylindrical, and three-dimensional Cartesian element types, (including interfacial contact resistance elements) totalling three coordinate systems and ten element types, are supported. The accuracy and reliability of the simulator is demonstrated for several situations in which the analytical solution is known. Specific experimental cases discussed include a plasma-arc re-melting furnace, a cylindrical casting in both gray-iron and Al-13%Si, a steel rail-wheel casting in two configurations, and an investment-plate casting. The numerical simulations are in excellent agreement with experimental data in predictions of cooling rates, solidification times, and in the prediction of casting defects. Results are displayed on time-temperature plots, isotherm plots, and color temperature displays. Simulations of up to 1294 nodes and 984 elements are presented, with execution times varying from 12,000 seconds to 395,000 seconds.Ph.D.Chemical engineeringUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/160922/1/8612476.pd