单级冲击采样器切割头气流特性及切割粒径研究

Research on Airflow Characteristics and Cutting Particle Size of Cutting Head in Single-stage Impact Sampler

以单级冲击采样器切割头为对象,应用CFD技术,数值模拟了喷嘴末端平齐外壁(模型一)和喷嘴末端向下延伸(模型二)两种结构切割头内部的流场及颗粒物轨迹。模拟结果表明模型二具有以下特点:颗粒物更容易脱离流线而撞击在捕捉面上;√St数曲线较陡;能有效通过颗粒物粒径进行选择性捕捉;捕捉率曲线整体上更陡,对颗粒物的切割效果更理想。本文为单级冲击采样器切割头的设计提供了一定的技术参考。

The cutting head of the single-stage impact sampler is used as the object.Using CFD technology,the flow field and particle trajectory inside the cutting head of two structures are numerical simulated.The nozzle is even with outer wall edge in model 1,and the nozzle end extends downward in model 2.The simulation results show that the mode2 is more effective than the model 1.Particles are more likely to break away from flow path and dash against on the capture surface.The √St number curve is steep.It can effectively capture the particles selectively by the size.The capture rate curve of the model 2 is steeper on the whole,and the cutting effect of particles is more ideal.The conclusion provides a certain technical reference for the design of the cutting head of a single-stage impact sampler.