超音波噴霧メッシュ穴からの液滴形成過程の数値シミュレーション

抄録

Medical mesh nebulizers are used for inhalation therapy of respiratory diseases. In order to effectively manage drug delivery, the size of the generated micro-droplets must be controlled appropriately. As a basic research to develop a medical mesh nebulizer, the purpose of this work is to elucidate the droplet formation process from a 4 micron mesh hole (conical trapezoidal nozzle) of an ultrasonic nebulizer operating at 200 kHz. Numerical simulation of the droplet formation process up to 20 cycles of ultrasonic vibration was carried out for axisymmetric flow using OpenFORM. In the first cycle, no droplets were ejected from the nozzle. In the second to fourth cycles, unstable droplets are formed. After the fourth cycle, two successive droplets from the nozzle merged during two ultrasonic vibration cycles to form a 7-8 micron droplet. The droplets generated after the 4th cycle were found to be stable.