Development and performance analysis of a novel triple-anode plasma torch with annular powder feeding for high-efficiency powder processing

Direct current (DC) plasma torches play a pivotal role in the field of material processing, with their performance largely determined by the characteristics of the plasma jet. However, conventional DC plasma torches produce a plasma jet that has a small high-temperature region and a high velocity, which limits their powder processing rate. This paper introduces a novel triple-anode plasma torch (TAPT) equipped with annular powder feeding to address these challenges. Comprehensive investigation into the plasma jet characteristics of the TAPT was carried out through a combination of experimental measurements and numerical simulations. Results show that the TAPT produces an optimal plasma jet for powder processing, marked by a large high-temperature region, low velocity, and high uniformity. The plasma jet's peak temperature reaches over 20,000 K, with a 4,000 K region of 150 mm in length and 33 mm in diameter, and minimal regions exceeding a velocity of 80 m/s. The annular powder feeding of the TAPT guarantees a stable plasma jet for effective material processing, with the arc voltage exhibiting a small standard deviation of just 1.08 V. Furthermore, the TAPT’s efficacy in powder processing was exemplified by spheroidization trials involving aluminum oxide powder, which yielded an impressive energy efficiency of approximately 4.35 kWh/kg. Overall, the TAPT shows considerable potential in the field of powder processing, specifically in raising the efficiency of powder spheroidization processes.