Parametric effect investigation on surface heat transfer performances during cryogen spray cooling

• Published in: Applied thermal engineering 2018-10, Vol.143, p.767-776
• Main Authors: Tian, Jia-Meng, Chen, Bin, Zhou, Zhi-Fu
• Format: Article
• Language: English
• Subjects: 2D filter solution; Ambient temperature; Bubbles; Cooling effects; Cryogen spray cooling; Dermatology; Energy absorption; Epidermis; Heat conductivity; Heat transfer; Humidity; Injury prevention; Laser cooling; Melanin; Nozzles; Relative humidity; Spray cooling; Substrates; Surface heat transfer; Thermal conductivity
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2018.08.002

•Effects of ambient temperature and humidity on surface flux were investigated.•Best cooling capability can be obtained when ambient temperature (Ta) is 10 °C.•High Ta causes the decrease in droplet amount and increase in droplet temperature.•Frost formation under high relative humidity weakens cooling capability of CSC.•2D surface heat flux was obtained by filter solution method. Cryogen spray cooling (CSC) has been a widely used auxiliary tool in laser dermatology such as port wine stain to prevent unspecific thermal injury due to laser energy absorption by the melanin in the epidermis. The present paper presents an experimental research on the effect of ambient temperature, relative humidity, and initial substrate temperature on heat transfer performances during R134a spray cooling. Results demonstrated that the cooling capability of R134a spray cooling can be obtained with small ambient temperature (Ta = 10 °C) and relative humidity (RH = 25%). Further investigation of cooling mechanism was conducted by studying the temporal and radial heat transfer distributions with different spray distances and nozzles. The heat transfer distribution presented large non-uniformity along radial locations. Two uniform cooling sub-regions of 0 ≤ r