Characterization of jets for impulsively-started needle-free jet injectors: Influence of fluid properties

Pankaj Rohilla, Yatish S. Rane, I. Lawal, Andrew Le Blanc, Justin Davis, James B. Thomas, Cormak Weeks, Whitney Tran, Paul Fisher, Kate E. Broderick, Jonathan A. Simmons, Jeremy O. Marston

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


An experimental study was performed to assess the hydrodynamics of liquid jets used for needle-free injection, where the typical orifice diameter is ~155 μm and velocity is in range of ~ 60–140 m/s. The jet is impulsively started by a spring-piston that forces a plunger through a cartridge filled with the liquid. Liquid exiting the orifice then forms a jet. However, despite a fixed spring force, the jet speed can vary significantly depending on the fluid physical properties - in particular - the effective viscosity. Since in practice a wide range of fluids may be used for injection, we seek herein to study the jet formation and speed for a broad range of fluids, characterized by viscosity or rheological profile. In addition, we also characterize the jet performance with a peak impact force, measured by a dynamic load cell, and ex-vivo injection experiments on porcine tissue. We find that jet speeds and impact forces decrease in a non-linear fashion with increasing viscosity, but that shear-thinning effects are significant and can render high jet speeds (>100 m/s) even for low-shear viscosities μ0~100 Pa.s.

Original languageEnglish
Article number101167
JournalJournal of Drug Delivery Science and Technology
StatePublished - Oct 2019


  • Impact force
  • Liquid jet
  • Needle-free injection
  • Rheology


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