Simulation and experimental study on the influence of needle-free jet injection nozzle structure on injection performance

• Published in: Journal of drug delivery science and technology Vol. 68; p. 103043
• Main Authors: Wang, Zhizhi, Song, Dongxiao, Wang, Jian, Xiong, Liangcai, Shi, Tielin, Zhang, Chengsen, Di, Linsen, Zhang, Chunli, Zhang, Yade, Li, Haifei, Liu, Xin, Liu, Jing, Zhang, Yong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2022
• Subjects: Needle-free jet injection; Nozzle structure; Peak stagnation pressure; Peak turbulence intensity; SDOF solver; Simulation; UDF; Nozzle structure; Peak stagnation pressure; Simulation; UDF; SDOF solver; Needle-free jet injection; Peak turbulence intensity
• ISSN: 1773-2247
• DOI: 10.1016/j.jddst.2021.103043

Needle-free jet injection is an excellent alternative to conventional injection, which can reduce patients’ fear of needle and needle injury and reduce the probability of cross contamination. It is highly appropriate for the administration of small doses of medicines, such as vaccines and insulin. The structure of the needle-free jet injector nozzle determines the properties of the jet, and the optimized nozzle can improve injection performance. This study used the realizable k-ε turbulence model to study the effects of different nozzle cone angles and nozzle lengths on the injection effect. The peak stagnation pressure, jet velocity, and peak turbulence intensity were selected as the primary research parameters. We achieved a better nozzle structure with further analysis, and experiments were performed to verify the accuracy of the simulation model. The simulation results show that in the five nozzles with different taper settings, the nozzle with a smaller taper has higher jet velocity and peak stagnation pressure at the nozzle orifice and within a specific taper range. On the contrary, the nozzle with a smaller taper has a lower jet velocity at 4 mm away from the nozzle orifice. The effect of the nozzle length on peak stagnation pressure is limited and shows no apparent law, while the effect on the turbulence intensity is evident. The longer the nozzle length is, the less turbulence intensity is. At the same time, we also studied the influence of different viscosity liquids and different elastic coefficients of the driving spring on the injection performance. The jet impact force experiment was carried out. The results show that the simulation results are highly consistent with the experimental results, which verify the accuracy of the CFD model. The results provide ideas for optimizing the nozzle structure of commercial needle-free jet injector and help realize efficient drug delivery. [Display omitted] •The dynamic mesh method combined with SDOF solver is used to simulate the spring-piston injection system.•The compiled UDF is used to provide a gradually decayed elastic force to the piston.•The simulation results show that the influence of the nozzle structure on the peak stagnation pressure is completely opposite at the orifice and 4mm away from the orifice.•Adding a 0.5mm separation distance between the orifice and the skin will get better injection performance.