激光手术喷雾冷却中R404a液滴的蒸发特性  

Evaporation Characteristics of Single R404a Droplet in Laser Treatment of PWS in Conjunction with Cryogen Spray Cooling

作　　者：辛慧[1] 周致富[1] 王国祥[1,2] 陈斌[1] 王跃社[1] 

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049 [2]美国Akron大学机械工程系,akronoh44325

出　　处：《中国激光》2009年第10期2691-2695,共5页Chinese Journal of Lasers

基　　金：长江学者讲座教授配套项目;新世纪优秀人才计划项目(NCET-07-0661);教育部科学技术研究重点项目(107101)资助课题

摘　　要：制冷剂低温喷雾冷却是激光治疗葡萄酒色斑的主要辅助手段,可以有效保护表皮不受热损伤。目前采用的R134a制冷剂不易抵消深色人种皮肤的黑色素对激光能量的大量吸收,采用沸点更低的R404a制冷剂可以更好保护黄色与黑色人种的皮肤。针对单个液滴建立了蒸发过程的理论模型,水滴蒸发实验的预测结果与实验结果非常吻合,验证了模型的有效性。利用该模型比较了R404a液滴与R134a液滴的蒸发冷却效果,发现R404a液滴可以达到更低的温度。分析了不同初始直径和环境蒸气质量分数对R404a液滴蒸发特性的影响,所得结果对于黄色和黑色人种激光手术治疗鲜红斑痣的制冷剂喷雾手术有参考价值。Cryogen spray is an effective cooling technique for the laser treatment of port wine stain （PWS）, which can protect the epidermis from the thermal injuries safely. However, cryogen R134a cannot supply enough cooling capacity for the laser surgery in patients with darker skin because of the absorption of laser energy by melanin. Cryogen R404a are expected to protect the darker skin well because of its lower boiling point. A theoretical model is proposed to describe the evaporation process of single droplet and its validation is confirmed by the agreement between numerical simulation with experimental result. With this model, the cooling effect of R404a droplet is compared with R134a droplet and it is found that R404a droplet can reach lower temperature. Then the influences of initial diameter and ambient mass faction of cryogen on the evaporation characteristics of R404a droplet are analyzed and the result is useful to guide the cryogen spray cooling for laser therapy of PWS patients with darker skin.

关 键 词：医用光学 鲜红斑痣 激光手术 制冷剂喷雾冷却 液滴蒸发 

分 类 号：TK124[动力工程及工程热物理—工程热物理] R758.5[动力工程及工程热物理—热能工程]