Numerical Simulation Study on the Preparation Process of Perovskite Coatings by Supersonic Flame Spraying

超音速火焰喷涂被广泛应用于防腐耐蚀涂层的制备和修复。本研究以液体煤油为燃料，利用数值模拟软件Fluent对超音速火焰喷涂过程进行仿真分析，研究热喷涂过程中的焰流特性和La2O3粒子飞行特性。成功模拟了气体流动特性(温度、速度和压力)、气体成分的质量分数和颗粒特性。此外，还研究了氧油比、颗粒粒径以及喷涂距离对超音速喷涂制备涂层过程的影响。模拟结果表明，当氧油比为3时，喷枪内温度最高，燃烧最为充分，焰流的速度最高，焰流处于最佳状态。当燃料流率为0.02531 kg/s、O/F比例为3、喷涂距离小于150 mm时，La0.75Sr0.25MnO3粉体分解得到的粒径小于5 µm的颗粒可以达到La2O3熔点。Supersonic flame spraying is widely used in the preparation and repair of anti-corrosion and corrosion-resistant coatings. In this study, liquid kerosene was used as the fuel, and the numerical simulation software Fluent was employed to simulate the supersonic flame spraying process. The characteristics of the flame flow during the thermal spraying process and the flight characteristics of La2O3 particles were investigated. The flow characteristics of the gas (temperature, velocity, and pressure), the mass fraction of the gas components, and the particle characteristics were successfully simulated. Additionally, the effects of the oxygen-to-oil ratio, particle size, and spraying distance on the process of preparing coatings by supersonic spraying were studied. The simulation results show that when the oxygen-to-oil ratio is 3, the temperature inside the spray gun is the highest, the combustion is the most complete, the velocity of the flame flow is the highest, and the flame flow is in the best state. When the fuel flow rate is 0.02531 kg/s, the O/F ratio is 3, and the spraying distance is less than 150 mm, the particles with a size smaller than 5 µm obtained from the decomposition of La0.75Sr0.25MnO₃ powder can reach the melting point of La2O3.