摘要
制冷剂瞬态喷雾冷却是辅助激光手术治疗皮肤病的重要手段,目前采用的R134a制冷剂不易抵消深色人种表皮中的黑色素对激光能量的大量吸收,采用沸点较低的R404a制冷剂能更有效防止表皮的热损伤。使用带膨胀腔的新型喷嘴搭建了瞬态喷雾冷却实验台,采用薄膜热电偶快速测温技术对R404a瞬态喷雾冷却表面传热特性进行了研究。结果表明,R404喷雾冷却表面传热具有时间和空间的不均匀性,然而在喷雾中心半径2 mm的中心区域内存在高热通量的均匀冷却区域。在实际激光皮肤临床手术中,参考实验结果可保证喷雾冷却对治疗范围内的表皮进行均匀冷保护。
Cryogen spray cooling has been applied to protect epidermis from thermal damage during laser surgery. However, the presently used cryogen, R134 a shows unsatisfactory efficacy in minimizing laser energy absorption by melanin in darkly pigmented human skins. Previous work of our group showed that R404 a had the potential of improving cooling protection to epidermis, while there is few related research on the surface heat transfer during R404 a spray cooling. This paper presents an experimental study on the temporal and radial variation in temperature and heat flux during spray cooling using R404 a by a specially designed nozzle with expansion chamber, which significantly improved the atomization effect. The temporal and radial conditions strongly influenced uniformity of surface heat transfer. However, there existed a sub-region of uniform cooling with radius of 2 mm around spray center with high heat flux. The result of this experiment could provide guidance for guaranteeing uniform cooling protection during clinical laser surgery.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2015年第4期1258-1264,共7页
CIESC Journal
基金
国家自然科学基金重点项目(51336006)
中央高校基本科研业务费专项资金~~
关键词
表面
传热
汽化
R404A
喷雾冷却
surface
heat transfer
evaporation
R404a
spray cooling
