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Cavitation cloud dynamic characteristics of dual-chamber self-excited oscillatory waterjet
Dezheng Li,Yong Kang,Hanqing Shi,Yi Hu,Qi Liu,Hongchao Li,Jincheng Hu,Jiamin Li 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12
Aiming to enhance self-excited oscillating cavitation jet performance, the effect of the dual-chamber nozzlestructure on the jet dynamical characteristics was designed and investigated. With high-speed camera technology,the cavitation phenomenon was investigated to analyze the area pattern and shedding period of the cavitation cloudunder different nozzle structures. The results showed that the dual-chamber nozzle significantly improved the jet cavitationstrength, and the cavitation cloud area increased by 76% and decreased the shedding period by 90% comparedwith the single-chamber nozzle. In the upstream chamber, the upper shrinkage ratio had a more drastic effect on thecavitation cloud area and shedding frequency than the lower shrinkage ratio with a more sensitive effect on the sheddingfrequency. In the downstream chamber, the outlet diameter ratio and chamber diameter were more sensitive tothe regulation of cavitation cloud shedding frequency and area, respectively, with the optimal regulation at the outletdiameter ratio of 1 and chamber length of 6 mm. The chamber diameter modulated the cavitation cloud most drasticallywith a comprehensive performance optimum at 12mm, which the area fluctuation reached 76.8%. The resultsprovide a basis for further research and application of dual-chamber nozzles.
Experimental investigation on penetration performance of larger volume needle-free injection device
Dongping Zeng,Ni Wu,Lei Qian,Hanqing Shi,Yong Kang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9
The injection performance of a small volume of needle-free injection (up to 0.3 mL) has proven to be controllable and satisfactory in transdermal drug delivery. However, no comprehensive research on the behavior of larger volume injections with different requirements for clinical applications exists. This study aims to present the penetration characteristics of larger volume injections, including dynamic properties, dispersion pattern, and percent delivery. The researchers conduct impact and injection experiments with injection volumes from 0.1-1.0 mL, driving pressures of 0.5-1.75 MPa, and orifice diameters of 0.17-0.5 mm. This study uses high-speed photography and impact experiments to capture the dynamic properties of the liquid jet. The researchers observe the dispersion patterns of liquid penetration into the gels in the gel injection experiments and investigate the percentages of liquid delivered to the skin tissues in porcine tissues injection experiments. Moreover, this study uses the response surface methodology (RSM) to analyze the interactive effect between various injection parameters on the injection performance. Results describe the differences in penetration performance between larger volume injections and small volume injections, and the critical volume of the mentioned injections is approximately 0.6 mL.