Melt circulation as a function of the operating conditions and dimensions of the RH system were calculated using a 3-dimensional numerical model. This numerical model was developed with considering the driving force by gas blowing for melt circulation and was verified from both water model experiments and real RH process results.
Using the numerical model, the influences of various parameters on melt circulation were investigated. The parameters can be divided into two categories, the operating conditions and dimensions of RH system. The effects of each operating parameters such as gas flow rate, the pressure of the vacuum vessel and submerged depth of the snorkel on the melt circulation rate were studied. In addition, the effects of the dimension parameters of the RH system such as the number of nozzles and snorkel diameter were also investigated.
By synthesizing the calculated melt circulation for various conditions, a simple model, which can predict the melt circulation without calculating the three dimensional fluid flow, was developed. Using this prediction model, the effects of the various parameters on melt circulation could be calculated easily.