Comparative Study of Converging Nozzle and de Laval Nozzle for Liquid Atomization
To explore the influence of different types of micro-nozzles on the atomization in the transdermal drug delivery,this work takes a converging nozzle and a de Laval nozzle as the research objects.Firstly,the Phase Doppler Particle Analyzer(PDPA)is employed to measure the distributions of velocity and particle size of the droplets from the atomization of the two nozzles.Then,to understand the internal flow conditions,a dynamic pressure sensor is utilized to measure the gas pressure in the nozzle,and the Schlieren imaging is employed to observe the flow in the nozzle.Finally,a skin model is subjected to the impact test of high-speed droplets,where methylene blue solution and Evans blue solution are used as staining agents,and fresh pig ears are adopted as the test objects.The PDPA experiment shows that the atomization of the droplets through the de Laval nozzle is more complete than that through the converging nozzle.The experiment of the internal pressure measurement shows that there is a shock wave in the de Laval nozzle,indicating a supersonic speed at upstream.The Schlieren experimental results directly show that in the de Laval nozzle concerned in this study,the gas flow forms two staggered oblique shock waves,instead of a normal shock wave in the expansion section.The impact test of skin model indicates that the high-speed droplets penetrate through the layer of stratum corneum,which demonstrates the application potential of transdermal delivery of drugs in the aesthetic medicine industry.This work lays the foundation for further investigations of novel means for transdermal drug delivery.
converging nozzlede Laval nozzleatomizationPDPASchlieren imaging
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