多相介质诱发柱塞泵内部磨损

 为了突破油水煤浆作为替代燃料发展的瓶颈,解决油水煤浆替代柴油应用于柴油机和固体煤颗粒的存在加剧柱塞泵磨损问题,通过数值模拟和实验测试方法找出多相介质下诱发柱塞泵内部磨损的机制。采用VOF多相流动模型,对颗粒运动轨迹、颗粒与过流表面的相互碰撞过程、固液(煤、油)磨损进行了数值模拟,并试验测试分析。研究结果表明：离散相颗粒的性质(密度、粒径)、混合比例及柱塞运动速度对颗粒运动轨迹及壁面碰撞过程有重要的影响；大粒径、大密度的颗粒运动轨迹向柱塞泵壳体内侧偏移,与其撞击并反弹,易发生多次撞击,对柱塞泵壳体内侧磨损程度大；小颗粒易与柱塞偶件发生撞击,因柱塞偶件表面油膜颗粒一般与其发生一次撞击,冲蚀磨损相对弱些；凸轮速度直接影响柱塞运动速度,速度加剧内部磨损；混合燃料中固体颗粒的体积比增大,对柱塞偶件的磨损加剧,模拟结果与试验结果吻合。

Multi-medium Running Induced Piston Pump Erosion

In order to break through the bottleneck in the development for the oil-coal-water slurry to serve as the alternative fuels, this paper studies the problem of substituting the oil-coal-water slurry for the diesel fuel to be used on diesel engines where solid coal particles would exacerbate the piston pump wear, and carries out a multi-phase numerical simulation to identify the media-induced piston wear mechanism. Based on the VOF multi-medium model, the Reynolds stress model and the discrete phase model for the continuous phase and the dispersed phase, the multi-medium erosion, the motion trajectory of the solid particle and the impact process between the solid particle and the machine surface are simulated. The volume content of the solid phase in the multi-medium flow is lower than 10% in this simulation model. The simulation result shows that, the related parameters of the solid particles, such as the density and the diameter, the mix proportion and the plunger speed of the impeller, would greatly influence the motion trajectory and the impaction of the solid particles with the machine surface. The solid particles with a large mass are apt to move toward the working surface and impact the inside of the piston shell. On the other hand, the small particles are liable to impact the plunger barrel assembly. The higher the plunger speed, the more plunger barrel assembly erosion will be resulted; the plunger barrel assembly wears more severely with the increase of the solid mix proportion. Simulation results agree with experimental results.