Model of Solute Surface Tension Convection and Its Analysis for Space Experiment
溶质表面张力对流模型及其对空间实验的解析

Space High Temperature In Situ Observation Instrument " SHITISOI" was dedicated to visualize and record the whole KNbO3 cellular growth process in Li2B4O7 flux. The dependence of buoyancy and surface tension convections on the cellular growth was studied. In space, the streamlines of the steady surface tension convections in the Li2B4O7 flux were observed. The steady convections occur in the form of a mirror symmetric pattern. Due to the surface tension convection, the KNbO3 grains grow and fill the whole solution homogeneously. On the ground,the buoyancy drive flow in direction opposite to that of surface tension flow can reduce the cellular growth and the distribution of KNbO3 soIute grains is inhomogeneous in the Li2B4O7 fiux. A theoretical model of cellular growth was also accounted. A pivotal feature in this model is the initiation of the surface tension convection on the interface of KNbO3 grain. This is initiated by KNbO3 solute surface tension gradient which is caused by less rapid diffosion of KNbO3 solutes.Direct compaxison of the model predictions and experimental observed phenomena demonstrates the predictive capability of this model.