一种医用射流雾化器工作原理的仿真与分析

雾化吸入是临床上常用的介入手段,可帮助气管切开患者进行机械通气,也能够以更有效地方式为呼吸道疾病患者给药。研究从雾化的基本原理着手,分析典型雾化器的几何结构,根据作用机理将雾化过程划分为毛细上升,喷口雾化及撞击回流和气溶胶喷出等三个阶段,并结合流体体积法对雾化过程所涉及到的二相流动进行数值分析。稳态分析结果验证了喷口处由于气流压力小于大气压而产生的负压,确认了毛细上升过程中驱动药液运动的核心动力。瞬态分析结果发现药液沿着液膜-液丝-液滴的流程逐渐雾化成液滴。这些分析结果厘清了雾化器的基本工作过程,对后续雾化器的性能表征和结构优化设计具有指导意义。

Simulation and Analysis of Medical Jet Nebulizers

For years, medical nebulizers have been prevalent for mechanical ventilation and aerosolized drug delivery in clinical applications. The present contribution aims at elucidating the basic working principles of medical nebulizers. The process of atomization is found to be comprised of three stages: capillary rise in the slit, atomization at the nozzle, and aerosol discharge in the cup. Based on typical geometric structure of nebulizers, we conduct a series of numerical analysis of the atomization process with the help of Volume-of-Fluid method. Steady state analysis shows that air pressure at the nozzle is smaller than the local atmospheric pressure, resulting in a negative pressure that drives the liquid medicine up in the capillary slit. Transient analysis elucidates that the whole atomization process follows the path from liquid film to liquid thread and finally to liquid droplets. The current analysis clarifies the physical mechanisms behind nebulizers and provides guidance for the future design, characterization and optimization of nebulizers.