Granulometric Characteristics Study for the Particles of the Cu2-xS - Fex+1S System

The electrolysis of granular matte is a new alternative method for processing sulphide copper materials with the production of cathode copper and the conversion of sulfur to the elemental state. For the first time were established the regularities for the Cu2-xS – Fex+1S granules distribution by the size classes of obtained granulations for the Cu - Fe - S melt at temperatures of 1200, 1250, 1300 and 1350 °C. The maximum amount of Cu2-xS – Fex+1S material of size class 5.0 + 2.5, -2.5 + 1.6 and-1.6 + 1.0 mm, which corresponds to the conditions of following electrochemical processing and estimated as 72.5%, was obtained by granulation of the melt at 1200 °C. The granulometric characteristics of Cu2-xS – Fex+1S granules were estimated. With an increase in the overheating temperature of the Cu - Fe - S melt, granules with a large value of the average diameter were obtained, also the root-mean-square deviation of the particle size from the average value increases and the degree of polydispersity of the granules decreases. The duration of cooling for Cu2-xS – Fex+1S granules from the melt temperatures at 1200, 1250, 1300 and 1350 °C was calculated. In the entire considered temperature range, the particle cooling time is much longer than the spheroidization time, which contributes to the formation of spherical particles.

Prompt Transient Heat Transfer Effects in Low-Fluence Laser Induced Incandescence

Recent time-resolved laser-induced incandescence (TiRe-LII) experimental studies have revealed anomalies in particle cooling rates that cannot be explained using steady-state conduction models. This is the first study to use Direct Simulation Monte Carlo (DSMC) to investigate possible transient effects in heat conduction between the laser-energized particle and surrounding gas. While the DSMC results reveal an increased cooling rate shortly after the laser pulse, this effect is small relative to experimentally-observed anomalous cooling.

An Extension of the Large-Cell Radiation Model for the Case of Semitransparent Nonisothermal Particles

The recently developed model for thermal radiation in multiphase flows typical of melt-coolant interactions is generalized to account for transient temperature profile in large semitransparent particles of solidifying melt. A modification of the large-cell radiation model (LCRM) is based on the approximate solution for coupled radiation and conduction in optically thick spherical particles of a refractive material. The simplicity of the suggested approximation enables one to implement the modified model in a multiphase computational fluid dynamics code. The LCRM extension makes possible the use of this approach not only for the core melt in nuclear fuel-coolant interactions but also for other melt substances, which are widely used in the laboratory experiments. The numerical data demonstrate an effect of absorption coefficient of the particle substance on the rate of particle cooling and solidification.

An Extension of the Large-Cell Radiation Model for the Case of Semi-Transparent Nonisothermal Particles

The recently developed model for thermal radiation in multiphase flows typical of melt-coolant interactions is generalized to account for transient temperature profile in large semi-transparent particles of solidifying melt. A modification of the Large-Cell Radiation Model (LCRM) is based on approximate solution for coupled radiation and conduction in optically thick spherical particles of a refractive material. The simplicity of the suggested approximation enables one to implement the modified model in a multiphase CFD code. The LCRM extension makes possible the use of this approach not only for the core melt in nuclear fuel-coolant interactions (FCI’s) but also for other melt substances which are widely used in the laboratory experiments. The numerical data demonstrate an effect of absorption coefficient of the particle substance on the rate of particle cooling and solidification.