数值模拟喷射夹角对VIGA制粉雾化过程的影响

通过计算流体力学软件数值模拟和实验相结合的方法,以高温合金雾化过程中气、液、固三相的交互作用机制为研究对象,采用欧拉-拉格朗日法的VOF(volume of fluid)多相流模型和DPM(discrete phase model) 离散相方法,研究了喷射夹角对熔体主雾化和二次雾化过程TAB(Taylor analogy breakup)破碎过程和粒度分布的影响,并与同步实验结果进行了对比.研究结果表明,随着喷射夹角的增大,回流区面积逐渐减小.金属熔体的初次破碎形态呈“倒喷泉状→伞状”,初次液滴的尺寸为0.3~0.9mm.初次破碎液滴的气体韦伯数(We)为10~90,随喷射夹角的增大,粉末的平均粒径逐渐降低,喷射夹角为36°时,实验制备的粉末粒径与数值模拟得到的粉末粒径基本一致,表明了数值模拟合金雾化破碎过程的合理性.

Numerical Simulation of the Intersection Angle Influence on Atomization Process of Powders Produced by VIGA

The effect of intersection angle on the primary and secondary atomization of vacuum induction melting gas atomization (VIGA) was studied by the combination of experiments and computational fluid dynamics CFD simulations. The VOF (volume of fluid) multiphase flow model based on the Euler-Lagrange method was used to simulate the primary atomization process and the discrete phase model (DPM) was used to simulate the breakup process and predict the particle size distribution (PSD) of Taylor analogy breakup (TAB) in secondary atomization. The results show that the simulated area of recirculation zone decreases with the increase of intersection angle. The fragmentation morphology of metal melt is presented as "fountain→umbrella" and the primary droplets size is 0.3~0.9mm. The Weber number (We) of liquid droplets is 10~90. With increasing intersection angle, the average particle size of the powders decreases gradually. Moreover, these simulation results prove reasonable, which the simulated particle size of the powders is in agreement with the experimental one when the intersection angle is 36°.