Hsieh Shou-Shing, Tsai Huang-Hsiu
Department of Mechanical and Electro Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung, 80424, Taiwan, ROC.
Arch Dermatol Res. 2006 Jul;298(2):82-95. doi: 10.1007/s00403-006-0663-3. Epub 2006 Apr 6.
The performance of single sprays for high heat flux cooling using R-134a was studied. The heat flux and heat transfer coefficient at the surface of a sprayed jet based on measurements of steady-state temperature gradients on a thin copper plate during continuous spraying. Meanwhile, the spray droplets flow characteristics was also quantified through laser doppler velocimetry (LDV) measurements to obtain the local velocity distributions. The effects of mass flow rate and average droplet velocity, and spray exit-to-target distance on the surface heat flux including the corresponding critical heat flux (CHF) were explored through three different nozzle diameters of 0.2, 0.3, and 0.4 mm. Finally, the effective use of the fluid being delivered based on the cooling efficiency and cooling effectiveness was also examined. The relationship between CHF and nozzle performance in terms of cooling efficiency and cooling effectiveness was found. The heat transfer removal rate can reach up to 140 W/cm(2) for the present nozzle size of d (j)=0.2 and 0.3 mm, which may enhance the current cryogen spray cooling (CSC) technique that assists laser therapy of dermatoses.
研究了使用R - 134a进行高热流冷却的单股喷雾性能。基于连续喷雾过程中薄铜板上稳态温度梯度的测量，得到了喷雾射流表面的热流和传热系数。同时，还通过激光多普勒测速仪（LDV）测量对喷雾液滴流动特性进行了量化，以获得局部速度分布。通过0.2、0.3和0.4毫米三种不同的喷嘴直径，探讨了质量流率、平均液滴速度以及喷雾出口到目标距离对表面热流（包括相应的临界热流，CHF）的影响。最后，还基于冷却效率和冷却效果研究了所输送流体的有效利用情况。发现了CHF与喷嘴在冷却效率和冷却效果方面性能之间的关系。对于当前d(j)=0.2和0.3毫米的喷嘴尺寸，传热去除率可达140 W/cm²，这可能会改进当前辅助皮肤病激光治疗的低温喷雾冷却（CSC）技术。
