Computational study of fluid flow in tapered orifices for needle-free injectors
Computational study of fluid flow in tapered orifices for needle-free injectors
复制标题
无针注射器锥形孔内流体流动的计算研究
DOI：
10.1016/j.jconrel.2020.01.013
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发表时间：
2020
影响因子：
10.8
通讯作者：
Marston, Jeremy O.
中科院分区：
文献类型：
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作者：
Rane, Yatish S.;Marston, Jeremy O.
使用弹簧动力喷射注射的经皮给药已经研究了几十年，由于有针对性的无针技术的出现，特别是对于粘性和复杂的液体，这种技术继续受到高度追捧。因此，本文报告了数值模拟的结果，以研究流体流变学和弹匣几何形状对射流出口速度、总压降和边界层厚度等特性的作用，因为这些都是影响射流稳定性和准直的因素。数值方法涉及不可压缩定常流动，并基于孔口处系统雷诺数（Re=ρdovj/μ）建立湍流模型。实验结果表明，在较大雷诺数范围内（101<Re< 104）， Re< 102时无量次压降（Eu= 2∆P/ρvj2）急剧下降，Re≥104时逐渐接近无粘极限。通过将研究扩展到非牛顿流体，其流变曲线近似于careau模型，我们还阐明了不同流变参数的影响。最后，通过研究一系列喷嘴几何形状，如锥形、s形锥度和多层锥度，我们观察到流体加速度抑制了边界层的生长，这表明可能存在针对特定组织深度创建射流的最佳几何形状。
Transdermal drug delivery using spring-powered jet injection has been studied for several decades and continues to be highly sought after due to the advent of targeted needle-free techniques, especially for viscous and complex fluids. As such, this paper reports results from numerical simulations to study the role of fluid rheology and cartridge geometry on characteristics such as jet exit velocity, total pressure drop and boundary layer thickness, since these all factor in to jet stability and collimation. The numerical approach involves incompressible steady flow with turbulence modelling based on the system Reynolds number at the orifice (Re=ρdovj/μ). The results are experimentally validated for a given geometry over a wide range of Reynolds numbers (101<Re< 104), and our results indicate a sharp decrease in dimensionless pressure drop (Eu= 2∆P/ρvj2) forRe< 102)and gradually approaching the inviscid limit atRe≥ 104. By extending the study to non-Newtonian fluids, whose rheological profile is approximated by the Carreau model, we also elucidated the effect of different rheological parameters. Lastly by studying a range of nozzle geometries such as conical, sigmoid taper and multi-tier tapers, we observe that fluid acceleration suppresses the boundary layer growth, which indicates there may be optimal geometries for creating jets to target specific tissue depths.