Effects of different characteristic surfaces at initial stage of frost growth  

作　　者：蔡亮 侯普秀 王荣汉 张小松 

机构地区：[1]School of Energy and Environment,Southeast University [2]School of Automotive Engineering,South China University of Technology

出　　处：《Journal of Central South University》2010年第2期413-418,共6页中南大学学报（英文版）

基　　金：Project(50376052) supported by the National Natural Science Foundation of China;Project(307013) supported by the Key Project of Chinese Ministry of Education;Project(2008BAJ12B02) supported by the National Science and Technology Pillar Program in the 11th Five-Year Plan Period

摘　　要：The effects of surface energy on phase change of water vapor at initial stage of frost growth were studied to find an effective method of restraining frost growth.The mechanism of restraining frost growth by low energy surface(bigger contact angle) was analyzed based on crystal growth theory.Then,the phase change of water vapor and the process of frost growth on the copper and wax energy surfaces were observed using microscope.The results indicate that it is difficult for wax surface(low energy surface),on which there are still water droplets at 100 s,to form critical embryo,so frost growth can be restrained in a way.Water formation,droplet growth,ice formation and dendritic ice growth processes happen on both surfaces,ordinally.But the ice beads,with larger average diameter and sparse distribution on the wax surface,form later(at about 300 s) than that on the copper surface,and the dendritic ice also appears later.All of these support that ice crystal formation and dendritic crystal growth at initial stage of frost growth can be retarded on the low energy surface.The effects of surface energy on phase change of water vapor at initial stage of frost growth were studied to find an effective method of restraining frost growth. The mechanism of restraining frost growth by low energy surface （bigger contact angle） was analyzed based on crystal growth theory. Then, the phase change of water vapor and the process of frost growth on the copper and wax energy surfaces were observed using microscope. The results indicate that it is difficult for wax surface （low energy surface）, on which there are still water droplets at 100 s, to form critical embryo, so frost growth can be restrained in a way. Water formation, droplet growth, ice formation and dendritic ice growth processes happen on both surfaces, ordinally. But the ice beads, with larger average diameter and sparse distribution on the wax surface, form later （at about 300 s） than that on the copper surface, and the dendritic ice also appears later. All of these support that ice crystal formation and dendritic crystal growth at initial stage of frost growth can be retarded on the low energy surface.

关 键 词：frost growth surface characteristic contact angle wax coat 

分 类 号：TK172[动力工程及工程热物理—热能工程] P426.322[天文地球—大气科学及气象学]