An investigation of the influence of natural convection on tin solidification using a quasi two-dimensional experimental benchmark

A well validated, quasi two-dimensional, unsteady solidification experimental benchmark is proposed to study the critical role of thermally driven natural convection using commercial pure tin. The experiment consists of solidifying a parallelipedic sample from two vertical sidewalls using two heat exchangers in a rectangular cavity. The mean temperature gradient G(T), and the mean cooling rate C-R, are set to control the experimental process. An array of 50 thermocouples allows us to measure the instantaneous temperature field and its evolution. While in the liquid state, the isotherms exhibit a plausible convective heat flow and its intensity increases as the Rayleigh number increases. In the solidification process, a novel recalescence phenomenon is observed by tracing the solidifying front in a relatively slow cooling rate case. By setting different mean temperature gradients, different patterns of the natural convection and the temperature field evolutions are obtained. A discussion is also presented regarding the crystallography. (c) 2009 Elsevier Ltd. All rights reserved.