R404a喷雾冷却表面传热特性的时空不均匀性  

Temporal and radial dependent profiles for surface heat transfer during R404a spray cooling

作　　者：王锐[1] 周致富[1] 白飞龙 陈斌[1] 王国祥[1,2] 

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,ohioakron44325

出　　处：《化工学报》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~~

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.

关 键 词：表面 传热 汽化 R404A 喷雾冷却 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TQ026.4[动力工程及工程热物理—热能工程]