Effects of convection on physical vapor transport of Hg₂Cl₂ in the presence of Kr - Part I: under microgravity environments

Abstract

Special attention in the role of convection in vapor crystal growth has been paid since some single crystals under microgravity environments less than 1 g 0 exhibits a diffusive-convection mode and much uniformity in front of the crystal regions than a normal gravity acceleration of 1 g 0 . The total molar fluxes show asymmetrical patterns in interfacial distribution, which indicates the occurrence of either one single or more than one convective cell. As the gravitational level decreases form 1 g 0 down to 1.0 × 10 −4 g 0 , the intensity of convection, indicative of the maximum molar fluxes, is reduced significantly for ∆T = 30 K and 90 K. The total molar fluxes decay first order exponentially with the partial pressure of component B, PB (Torr) for 20 Torr ≤ P B ≤ 300 Torr, and two gravity accelerations of g y = 1 g 0 and 0.1 g 0 .

Numerical Analysis for Impurity Effects on Diffusive-convection Flow Fields by Physical Vapor Transport under Terrestrial and Microgravity Conditions: Applications to Mercurous Chloride

“…Detailed data such as typical process parameters and physical properties for the operating conditions could be found in Refs. [27][28][29].…”

“…(2)-( 4), which can be found in Refs. [27][28][29]. The density of the vapor mixture of component A (Hg2Cl2) and B (I2) is assumed constant except the buoyancy body force term, which would be a function of both temperature and concentration.…”

“…In study we employ a material of Hg2Cl2 as a model sample and investigate numerically the influence of gravitational accelerations on diffusive convection during the PVT of a mixture of Hg2Cl2 vapor and impurity of I2. The distinction of this study in a comparison with our previous study [27][28] is centered into the effects of gravitational accelerations and the partial pressure of component I2 with high molecular weight through numerical simulations of vector, streamline, temperature and concentration profiles.…”

Effects of Solutally Dominant Convection on Physical Vapor Transport for a Mixture of Hg2Br2and Br2under Microgravity Environments

“…The physical and mathematical formulations and many assumptions could be found in Refs. [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For simplicity, detailed assumptions used in this analysis are not described here.…”

“…Schematic and coordinates for modelling and simulation of PVT crystal growth reactor of Hg 2 Br 2 (A)-Br 2 (B), adapted from Ref [7]…”