Experimental and Numerical Investigation of the Bridgman Growth of a Transparent Material

Abstract

A combined experimental and numerical study of the horizontal Bridgman growth of pure succinonitrile (SCN) has been performed. The effect of convection on interface propagation and shape is quantified and discussed. Measurements were obtained both under conditions of nogrowth and for a 40 µm/s growth rate. The quantities measured include interface shape and location, melt velocities, and temperature boundary conditions on the ampoule exterior. The melt velocities were measured using a new technique that employed digital cameras to image the locations of seed particles in the melt. The growth front was stable and non-dendritic, but was significantly distorted by the influence of convection in the melt and, for the growth case, by the moving temperature boundary conditions along the ampoule. Both two-and three-dimensional numerical simulations of the growth process were performed. Temperatures throughout the phase change material and ampoule as well as melt velocities were obtained from the simulations. The predicted interface shapes and melt velocities agree well with experimental results. Two different numerical algorithms were used; the utility of each for simulating phase-change problems is discussed. This combined experimental and numerical study provides a database for the validation of phase-change numerical models, in addition to furnishing detailed information about the influence of convection on the Bridgman growth process. In ongoing work, the computer models presented in this study are being used to simulate alloy solidification problems.

Fixed-Grid Front-Tracking Algorithm for Solidification Problems, Part Ii: Directional Solidification With Melt Convection

“…A different set of simulations were performed to simulate experiments on horizontal Bridgman crystal growth performed in related work [16]. Interface shapes and locations, temperature traces and melt velocities were measured in [16] in order to generate a database against which numerical simulations of solidification processes could be compared.…”

“…3(a), the diffusion coefficients for the discretized equation need to be redefined as well. Equation (10) (16) which can be written as…”

“…Next, simulations of the Bridgman growth of pure succinonitrile (SCN) were performed, under both no-growth and growth conditions. Again, the results from the numerical solution scheme were compared with experimental and numerical data from the literature [16]. The experimental data in [16] were obtained under carefully controlled conditions with a view to benchmarking numerical simulation techniques, and included melt velocity data.…”

“…Again, the results from the numerical solution scheme were compared with experimental and numerical data from the literature [16]. The experimental data in [16] were obtained under carefully controlled conditions with a view to benchmarking numerical simulation techniques, and included melt velocity data. It was found that the results produced with the front-tracking algorithm agreed well with the experimental data, and were able to more accurately represent the front location than the numerical simulations reported in the literature, which did not explicity track the front.…”

Analysis of a Phase Change Energy Storage System for Pulsed Power Dissipation

“…For all the governing equations, iterations were terminated when the residual [18] dropped below 5 × 10 -6 . The numerical code used in the present work has been previously validated and extensively benchmarked [19,20,21] against results in the literature for natural convection in a box, Rayleigh-Benard convection, 1-d melting problem (classical Stefan problem), directional solidification of tin, and Bridgman growth of succinonitrile. Grid independence was verified by evaluating the interface shape predicted using a series of increasingly finer meshes.…”