Numerical Studies of Particle-Gas Two-Phase Flowing through Microshock Tubes
Numerical Studies of Particle-Gas Two-Phase Flowing through Microshock Tubes
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DOI：
10.1155/2021/6628672
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发表时间：
2021-02
影响因子：
1.6
通讯作者：
Guang Zhang;Wei Wang;X. Su;X. Li;W. Shen;Zhe Lin
中科院分区：
文献类型：
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作者：
Guang Zhang;Wei Wang;X. Su;X. Li;W. Shen;Zhe Lin
在航空航天和医学工程领域，微激波管常用于诱导激波和超声速流动。一种包括微激波管和膨胀喷嘴的无针药物输送装置，用于在没有任何注射器或疼痛的情况下通过皮肤表面输送固体药物粉末。因此，为了提高无针给药装置的性能，研究微激波管诱导的激波和颗粒-气体流动具有重要意义。尽管人们对微激波管中释放的激波和多相流进行了几十年的研究，但颗粒-气体非定常流动的特性至今仍不清楚。本研究采用三种微激波管模型进行数值模拟。采用一个端部封闭的微激波管模型，观察反射激波及其后的流动特性。另外两种模型分别在驱动段出口处设计声速喷嘴和超声速喷嘴，研究不同喷嘴诱导的颗粒-气体流动。采用离散相法（DPM）模拟非定常颗粒-气体流动，采用离散随机游走模型记录非定常颗粒的运动轨迹。数值结果与实验压力测量和颗粒可视化结果进行了比较。数值模拟结果与实验结果吻合较好。由于反射激波引起的储层压力，微粒在微激波管出口加速。声速和超声速喷管在微激波管末端均未充分膨胀。计算得到颗粒速度小于气体速度，这是由于注入颗粒阻力较大造成的。
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.