Atomization and surface heat transfer characteristics of cryogen spray cooling with expansion-chambered nozzles
发布时间：2025-04-30
点击次数：
- 发布时间：
- 2025-04-30
- 论文名称：
- Atomization and surface heat transfer characteristics of cryogen spray cooling with expansion-chambered nozzles
- 发表刊物：
- International Journal of Heat and Mass Transfer
- 摘要：
- Cryogen spray cooling (CSC) is commonly applied in laser dermatology to protect the epidermis from
thermal damage. Many efforts have attempted to improve the cooling capacity of CSC, among which
the use of expansion-chambered nozzles is an effectively simple method with considerable potential.
This study examined the influences of the expansion-chambered nozzle structure, including the ratios
of inlet nozzle diameter to discharge nozzle diameter and of chamber diameter to discharge nozzle diameter
on R134a and R404A spray cooling. Fifteen transparent expansion-chambered nozzles with the
expansion chamber aspect ratio of 1.0, chamber diameter to discharge nozzle diameter ratios of
5.0–10.0, and inlet nozzle diameter to discharge nozzle diameter ratios of 0.6–1.4 were tested. The internal
flow pattern inside the expansion chamber, external spray pattern, and surface heat transfer characteristics
of cryogen spray using different nozzles, including the straight-tube nozzle, were investigated.
The structure of the expansion chamber was found to have an important effect on the spray patterns
and cooling characteristics. The spray radius obviously decreased when the expansion-chambered nozzles
were used, and the spray pattern became narrower as the ratio of chamber diameter to discharge
nozzle diameter increased. By contrast, the increase in ratio of two nozzle diameters enlarged the spray
radius. Surface temperature and heat flux with different nozzles and cryogens showed a similarity, and
correlations of surface temperature and heat flux were proposed. The introduction of expansionchambered
nozzles could effectively improve the spray cooling capacity. The minimum average surface
temperature during the fully developed spray period could be reached for both R134a spray and R404A
spray by an expansion-chambered nozzle with a chamber diameter to discharge nozzle diameter ratio of
roughly 5.0 and an inlet nozzle diameter to discharge nozzle diameter ratio of roughly 0.6.
- 合写作者：
- Xin-Sheng Wang, Bin Chen ⇑, Zhi-Fu Zhou
- 卷号：
- 121
- 页面范围：
- 15-27
- 是否译文：
- 否
- 发表时间：
- 2017-12-29