Specifying interfacial heat transfer conditions in permanent mold castings: A comparison of two promising techniques

The specification of coefficients of heat transfer at the mold-metal interface is perhaps the weakest link in modeling flow and freezing in permanent mold casting practice. Both temporally and spatially related aspects confound attempts to provide accurate simulations to the extent that many practitioners are skeptical of the results obtained. Much of the existing confusion relates back to the ways in which thermocouple data is handled. This paper describes the comparison of two techniques, evaluated by the use of an analytical, triangular heat flux profile that is commonly used in the literature for comparison purposes. The two techniques are the singular value decomposition (SVD) model reduction and the frequency domain solution (FDS) as proposed by Marquardt and Blum and modified by the authors. Numerical simulations show that the modified FDS solution is comparable to the SVD solution with the added advantage of being an easily implementable, recursive technique.