The Research On Several Factors Affecting Needle-free Injection Performance

At present,the traditional stainless steel needle for liquid injection on the human body is widelyused at home and abroad. Although it even is operated by professional medical staffs,it may also causeintense pain. Once the use of non-sterile injecting is applied when the needle penetrated into the body,it may then transmitted viruses, or high likelihood of severe infectious diseases, which may be verydangerous. Therefore, injection safety is a hot topic as the world’s attention to the field ofmedicine.Needle-free injection technique has the advantage of painless compliance, good performanceof taken-in drug, non-cross infection and simple operation, the application of which can be a goodsolution to this problem.In this thesis, considering strutural characteristics of the spring-loader needle-free, it introducesthe friction between the rubber core rod and the wall of the syringe in detail,and take its existence intoaccount to consider its influence on the jet. Base on Baker model, Its impact is fully analyzed bycomparing its data to the experiment data through which the realiability of the friction model isvefified.At last,All its factors which might effect the friction are compared by analyzing the simulationoutcome.With the combination of thereotical model and experiment method,the process of needle-freeinjection is divided into three periods,and the mathematical model of the deformation of the epidermisafter the jet impact is set up,which improves the process of the needle-free injection analysis. And theminimum jet speed and the jet stagnant pressure which are required to penetrate the epidermis ofdifferent thickness at different nozzle diameter can be solved by this model,so can the spring stiffnessunder different nozzle diameters in the reverse way.At last,the reliability of the model is verified byexperiments.Finally,the various factors which impact the hole depth are analyzed in whole and the factors ofliquid dose, the spring stiffness coefficient, the percentage of polyethylene and the distance betweenpolyethylene and the nozzle within a certain range is verified by experiments.Also the qualitativeanalysis of spring stiffness, the percentage of polyethylene and the distance under the condition of acertain dose is done,which can provide a theoretical support to the research and the development ofneedle-free device.