Flow Characteristics and Heat Transfer Mechanism of the Al Powder in the Preparation Processing of High-Quality Aluminum Nitride Powder by Using the Laminar Plasma Jet

The high-quality aluminum nitride (AlN) powder is always prepared industrially by using the direct nitriding and carbothermic reduction method at present. However, considering their disadvantages of these methods, such as low production efficiency and complex post-treatment process, alternative preparation techniques should be considered. For generating the AlN powder, there are three main factors that should be considered: high temperature, aluminum (Al), and nitrogen (N₂) resources. Considering the rich N⁺ resource and high temperature in the laminar plasma jet (LPJ), the Al powder could be injected into the LPJ to prepare the AlN powder. For improving the quality of the prepared AlN powder, the interaction mechanism of the flow characteristics and heat transfer between the Al powder and the LPJ should be considered. Therefore, the interaction mechanism between LPJ and Al powder was explored based on the discrete phase model (DPM) built into Fluent. With this simulation model, the flow characteristics and heat transfer between the Al powder and the LPJ under various working conditions were studied. The results of this work are summarized as follows. With the increase of the LPJ power, powder feeding angle, the carrier gas flow rate, and powder feeding rate, more Al powder reaches its synthesis temperature area, which may lead to a higher purity of the prepared AlN powder.