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Numerical Studies of Particle-Gas Two-Phase Flowing through Microshock Tubes
Shock and Vibration ( IF 1.6 ) Pub Date : 2021-02-15 , DOI: 10.1155/2021/6628672
Guang Zhang 1 , Wei Wei Wang 1 , Xiang Hui Su 1 , Xiao Jun Li 1 , Wen Hao Shen 2 , Zhe Lin 1
Affiliation  

Microshock tubes are always used to induce shock waves and supersonic flows in aerospace and medical engineering fields. A needle-free drug delivery device including a microshock tube and an expanded nozzle is used for delivering solid drug powders through the skin surface without any injectors or pain. Therefore, to improve the performance of needle-free drug delivery devices, it is significantly important to investigate shock waves and particle-gas flows induced by microshock tubes. Even though shock waves and multiphase flows discharged from microshock tubes have been studied for several decades, the characteristics of unsteady particle-gas flows are not well known to date. In the present studies, three microshock tube models were used for numerical simulations. One microshock tube model with closed end was used to observe the reflected shock wave and flow characteristics behind it. The other two models are designed with a supersonic nozzle and a sonic nozzle at the exit of the driven section, respectively, to investigate particle-gas flows induced by different nozzles. Discrete phase method (DPM) was used to simulate unsteady particle-gas flows and the discrete random walk model was chosen to record the unsteady particle tracking. Numerical results were obtained for comparison with those from experimental pressure measurement and particle visualization. Shock wave propagation was observed to agree well with experimental results from numerical simulations. Particles were accelerated at the exit of microshock tube due to the reservoir pressure induced by reflected shock wave. Both sonic and supersonic nozzles were underexpanded at the end of microshock tubes. Particle velocity was calculated to be smaller than gas velocity, which results from larger drag of injected particles.

中文翻译:

微粒气体两相流经微冲击管的数值研究

微震管在航空航天和医学工程领域中一直被用来诱发冲击波和超音速流动。包括微震管和膨胀喷嘴的无针药物输送装置用于通过皮肤表面输送固体药物粉末,而无需任何注射器或疼痛。因此,为了提高无针药物输送装置的性能,研究微冲击管引起的冲击波和颗粒气体流动具有重要意义。尽管已经研究了从微冲击管中排出的冲击波和多相流数十年,但不稳定的颗粒气体流的特性至今仍不为人所知。在本研究中,三个微震管模型用于数值模拟。使用一个具有封闭端的微震管模型来观察反射后的冲击波和其背后的流动特性。另外两个模型设计为分别在从动部分的出口处配备一个超声波喷嘴和一个超声波喷嘴,以研究由不同喷嘴引起的颗粒气流。使用离散相方法(DPM)来模拟不稳定颗粒气体的流动,并选择离散随机游走模型来记录不稳定颗粒的跟踪。获得了数值结果,与实验压力测量和颗粒可视化相比较。观察到冲击波传播与数值模拟的实验结果非常吻合。由于反射冲击波引起的储层压力,微粒在微震管出口处被加速。在微震管的末端,超声波喷嘴和超声波喷嘴都未充分扩展。计算得出的粒子速度小于气体速度,这是由注入粒子的较大阻力引起的。
更新日期:2021-02-15
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