Flow Field Analysis and Structure Optimization of High-Dose Multi-Hole Needle-Free Jet Injector

At present, the single-hole needle-free jet injector has a small injection dose and cannot complete a high-dose liquid injection at one time. This paper proposes a high-dose multi-hole needle-free jet injector to solve this problem. The flow field of the single-hole needle-free jet injector was analyzed by ANSYS Workbench platform, it is found that when the taper angle of the micro-hole is 20 and the aspect ratio is 1.4, the needle-free jet injector can gain a higher exit velocity. According to the simulation results, an orthogonal test was designed to optimize the contraction section of the multi-hole needle-free jet injector. The optimized scheme was obtained as follows: the taper angle of 10, the aspect ratio of 1.6, the diameter of the distribution circle of 2.6 mm, the contraction section length of 4.35 mm and the diameter of the micro-hole of 0.195 mm. And through the stress analysis of ampoule, it is verified that the optimized scheme can meet the mechanical property requirements of the material. The optimization results show that the dose can be up to 5 ml, a high dose than the traditional single-hole injector, and the injection speed is as high as 150 m/s, which can penetrate the skin without causing too much damage. The feasibility of the optimization scheme is further verified by skin injection simulation, velocity experiment and kinetic analysis.