摘要
针对核态沸腾过程,利用高速摄像机和红外热成像设备对光滑、微坑、均匀微柱和槽型微柱四种不同单晶硅表面的沸腾现象进行了在线可视观测,获得了各表面气泡动力学演变过程及局部温度演变规律,揭露了基于动力学过程的沸腾强化机理。由沸腾曲线可知,光滑硅表面,沸腾起始过热度为6℃,而三种微结构表面,起沸过热度为3～4℃;同时,微坑、槽型微柱和均匀微柱表面核态沸腾的CHF较光滑表面分别提高了109%、129%和140%。动力学演变过程则证明了微坑的存在为核化沸腾提供了核化点,有效降低了核化能垒、缩短了壁面蓄能阶段的时长。微柱的存在大幅度增加了气泡核化密度,减小了脱离直径,缩短了脱离时间,促进了沸腾表面温度的均匀化。
The high-speed video and high-speed infrared were used to visual measure the boiling phenomenon on four kinds of monocrystalline silicon surfaces including smooth,cavity,pitch and groove-pitch surfaces.The dynamic evolution process and the local temperature evolution law reveal the boiling enhancement mechanism based on the dynamic process.For the smooth silicon surface,the superheat is 6℃when the boiling starts under low heat transfer,and this superheat is around 3-4℃for the three micro-structured surfaces.In addition,compared with the smooth surface,the CHF for cavity,groove-pitch and pitch surfaces are increased by 109%,129%and 140%,respectively.According to the dynamic evolution of bubble,cavities provide the nucleation sites,decrease the nucleation barrier energy and shrink the energy accumulation stage.Pitches significant increase nucleation sites,decrease departure diameter and departure time of bubbles,which uniform the boiling surface temperature.
作者
陈宏霞
孙源
宫逸飞
黄林滨
CHEN Hongxia;SUN Yuan;GONG Yifei;HUANG Linbin(Energy Power and Mechanical Engineering Department,North China Electric Power University,Beijing 102206,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2019年第4期1309-1317,共9页
CIESC Journal
基金
国家自然科学基金项目(51576063)
2019年度装备预研教育部联合基金青年人才基金项目(6141A02033526)
关键词
微结构
池沸腾
气泡动力学
局部温度
高速红外
micro-structure
pool boiling
bubble dynamics
local temperature
high-speed infrared
