两阶段悬浮液超音速火焰喷涂喷雾运动蒸发模拟研究

Numerical Analysis of Spray Motion and Evaporation Characteristics in a Supersonic Two-stage Suspension Flame Spray Process

以两阶段悬浮液超音速火焰喷涂为对象,采用数值模拟方法建立了两相流动与传热模型,对悬浮液喷雾雾化、运动蒸发以及固体颗粒团聚物的析出和加热运动过程进行了模拟分析。结果表明:随着氮气质量流量的增大,沿中心轴线方向气流温度降低,但速度基本不变;径向注射的悬浮液体积流量约为100 mL/min时悬浮液可渗透到气流中心,雾化和蒸发效果最好;注射角为-15°时颗粒粒径显著减小,且以液态形式到达基板的颗粒减少,从而涂层质量得到提高。

Taking the supersonic two-stage suspension flame spray process as an object of study,a two-phase flow and heat transfer model was established using numerical method to simulate and analyze the atomization,motion and evaporation behavior of the suspension,as well as the precipitation and motion heating process of solid particles.Results show that as the mass flow of nitrogen increases,the temperature of the jet decreases along the center axis,but the flow rate does not change.When the volume flow of the suspension injected in radial direction is about 100 mL/min,the suspension can penetrate into the center of the jet,in which case,the effects of both the atomization and evaporation are the best.At the injection angle of-15°,the particle size could be significantly reduced,and the number of particles reaching the substrate in liquid form would be cut down,thereby improving the quality of the coating.