An experimental and numerical effort to simulate the interface deflection of YAG

Numerical modelling of instability and supercritical oscillatory states in a Czochralski model system of oxide melts

“…This flow pattern is characterized by an intensive descending flow near the axis, where the temperature changes rapidly. This region is interpreted sometimes as a "cold jet" and is a source of the experimentally observed so-called "cold plumes" and "cold jet" instabilities [5,9]. We observe also the velocity boundary layer near the crucible wall.…”

“…(10) we also assumed that the ambient temperature is equal to the temperature at the melt/crystal interface. This is apparently wrong for the realistic crystal growth, however it does correspond to the model experiments [5]. Defining hot melting T T T ∆ = − and using the geometric and material data of [5] we estimate the governing parameters as Pr=9.2, height/radius=0.92, the crystal to crucible radii ratio 0.5, Bi=0.1, Gr=1.90×10…”

“…This allows one to use various transparent fluids having similar Prandtl numbers, e.g. water, silicon oils, salt melts, as an experimental liquid and consequently the melt flow driven by buoyant convection, thermocapillarity and rotation can be mimicked experimentally (see, e.g., [5,9]). Computational modelling of these flows has been carried out by many authors, and has been reviewed in [4].…”

“…It is mandatory also to base such a benchmark exercise on the existing experimental setup, so that the numerical results can be validated against experiments. In this study we formulated a test problem for a Czochralski melt flow based on the recent experiments of Schawbe, Sumathi and Wilke [5]. This problem was treated by two independent computational codes which incorporate two different numerical approaches.…”

An intermittent transition to chaotic flow by crystal rotation during Czochralski growth

“…It was recently described in detail [2] where the properties of NaNO 3 melt can be found, too. This growth system was designed originally to study the interface deflection and how to influence it by crystal rotation.…”