MA: Validation and optimization of a numerical model for heat and mass transport in a multi-zone furnace for the ammonothermal crystal growth

4. Dezember 2025

Geng Chongwei –

In this study, a two-dimensional axisymmetric model of a three-zone furnace for the ammonothermal growth of nitride crystals was developed using CrysMAS software. The geometry of the model was constructed to closely match that of the real furnace, and the temperature boundary conditions were defined based on actual measurements at the furnace boundaries. The model encompasses the simulation of the temperature field within the entire furnace, including the furnace shell, the internal high-pressure autoclave, and the surrounding airflow field. Particular attention was paid to the temperature distribution in the regions where thermocouples were located, which served as key reference points for comparison with experimental measurements.
The model was validated by comparing simulation results with experimental data obtained under various reaction conditions in the three-zone furnace. Based on the observed deviations between the simulation and experimental results, the model was refined and improved. The possible causes of the remaining discrepancies were subsequently analyzed. Furthermore, by combining the experimental and simulation data, the parameters of the structured mesh were optimized to better describe the fluid behavior in the simulation. Dimensionless number analyses were also performed for different regions of the model to identify the dominant heat transfer mechanisms, thereby providing a deeper understanding of thermal transport phenomena within the three-zone furnace. The findings of this study lay a solid foundation for future investigations and further model development.

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