高温环境条件下低温不规则表面上的结霜特性  

Frosting characteristic on the cold irregular surface under high temperature environmental conditions

作　　者：张楠楠 汪元 岳晓菲 ZHANG Nannan;WANG Yuan;YUE Xiaofei(College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学空天科学学院,湖南长沙410073

出　　处：《国防科技大学学报》2024年第6期11-24,共14页Journal of National University of Defense Technology

基　　金：国家自然科学基金资助项目(11872373,12102466)。

摘　　要：预冷器换热通道空气侧壁面的结霜对预冷发动机整体性能具有重要影响。通过实验研究了三种具有不规则表面形貌结构的试件(Ra=0.97μm,Ra=1.78μm,Ra=1.92μm)在高温环境(T a=50℃)下的结露/结霜过程。主要研究了环境温度(T a取50℃和18℃)、表面温度(T w取-10.9℃、-23.0℃、-28.0℃)以及表面形貌结构对液滴凝结及霜层生长特性的影响,并将霜层的致密化机理进行了总结分类分析。实验结果表明,环境温度越高,表面温度越低,霜晶生长周期越短。在三种试件表面,越靠近试件边缘,凝结液滴出现时间越早,长大越快。此外,还发现表面形貌结构对液滴的凝结及霜层生长全过程均有影响,并将表面形貌结构对凝结的影响机理进行了初步分析,但是不规则表面形貌结构对霜层生长的影响机理仍需进一步深入研究。Frost formation on the air side of the heat exchange channels of the precooler has an important effect on the overall performance of the precooled engine.Condensation/frosting process of three kinds of specimens with irregular surface topography structure(Ra=0.97μm,Ra=1.78μm,Ra=1.92μm)in high temperature environment(T a=50℃)was studied experimentally.The effect of the ambient temperature(T a is 50℃and 18℃),surface temperature(T w is-10.9℃,-23.0℃,-28.0℃)and the irregular surface structure on frost crystal/condense droplet growth characteristic were studied.The densification mechanism of the frost layer was summarized and analyzed.The experimental results showed that the higher the ambient temperature,the lower the surface temperature,and the shorter the frost crystal growth cycle.On the surface of the three specimens,the closer to the edge of the specimen,the earlier the condensation droplets appeared and the faster it grew.Besides,it was also found that the surface morphology and structure have influence on the whole process of droplet condensation and frost layer growth.The mechanism of the surface topography structure on condensation was preliminary analyzed,but the mechanism of irregular surface topography structure on frost growth needs further study.

关 键 词：凝结 致密化机理 霜层生长特性 高温环境 

分 类 号：TK124[动力工程及工程热物理—工程热物理]