TY - GEN
T1 - Single droplet evaporation model in laser treatment of PWS in conjunction with cryogen spray cooling
AU - Zhi-Fu, Zhou
AU - Hui, Xin
AU - Bin, Chen
AU - Guo-Xiang, Wang
PY - 2008
Y1 - 2008
N2 - Cryogen spray is an effective cooling technique used for laser treatment of Port Wine Stain. The cooling process involves complex droplet evaporation and strong convective heat and mass transfer, therefore a deep understanding of spray characteristics is essential in order to optimize the nozzle design and improve the cooling efficiency of the spray. This paper presents a theoretical model to describe the equilibrium evaporation process of a single cryogen droplet in cryogen spray. The model considers mass transfer through Mass Transfer Number Method, the momentum transfer by selecting the suitable empirical correlation of drag coefficient, and heat transfer by taking into consideration of droplet evaporation and convective effect with ambient air. The influence of variable physical properties of R134a is also considered. Based on the validation by simulating the cooling stage of a hanging water droplet, this model is used to predict the temperature variation of cryogen droplets in cryogen spray, which is in reasonable agreement with the experimental measurements. A parametric study of the influences of initial diameter and velocity on the droplet evaporation is then carried out. The results can be used to guide the Cryogen Spray Cooling of laser therapy.
AB - Cryogen spray is an effective cooling technique used for laser treatment of Port Wine Stain. The cooling process involves complex droplet evaporation and strong convective heat and mass transfer, therefore a deep understanding of spray characteristics is essential in order to optimize the nozzle design and improve the cooling efficiency of the spray. This paper presents a theoretical model to describe the equilibrium evaporation process of a single cryogen droplet in cryogen spray. The model considers mass transfer through Mass Transfer Number Method, the momentum transfer by selecting the suitable empirical correlation of drag coefficient, and heat transfer by taking into consideration of droplet evaporation and convective effect with ambient air. The influence of variable physical properties of R134a is also considered. Based on the validation by simulating the cooling stage of a hanging water droplet, this model is used to predict the temperature variation of cryogen droplets in cryogen spray, which is in reasonable agreement with the experimental measurements. A parametric study of the influences of initial diameter and velocity on the droplet evaporation is then carried out. The results can be used to guide the Cryogen Spray Cooling of laser therapy.
UR - https://www.scopus.com/pages/publications/51549109302
U2 - 10.1109/BMEI.2008.279
DO - 10.1109/BMEI.2008.279
M3 - 会议稿件
AN - SCOPUS:51549109302
SN - 9780769531182
T3 - BioMedical Engineering and Informatics: New Development and the Future - Proceedings of the 1st International Conference on BioMedical Engineering and Informatics, BMEI 2008
SP - 551
EP - 556
BT - BioMedical Engineering and Informatics
T2 - BioMedical Engineering and Informatics: New Development and the Future - 1st International Conference on BioMedical Engineering and Informatics, BMEI 2008
Y2 - 27 May 2008 through 30 May 2008
ER -