摘要
针对蒸发器表面结霜造成空气流通面积减少,换热热阻和冰箱能耗增加的问题,搭建了竖直风道的蒸发器结霜测试平台,对蒸发器表面霜层沿空气流动方向的分布特性进行试验研究。采用定时拍摄装置分区测量了不同时间的霜层厚度,并计算了蒸发器表面平均霜层密度、平均导热系数。结果表明,当进口冷却液温度从-15℃降低至-20℃,区域4和区域5的堵塞率差异仅为8%,更低的冷表面温度有利于霜层的均匀分布;当相对湿度从75%增加到85%,平均堵塞率分别增大9.4%~55.7%。相对湿度的增大显著促进了霜层的增长;根据平板结霜的3个阶段,将导热系数、霜层密度随时间的变化分成急速生长期、匀速增长期、稳定期3个阶段;在结霜后期,平均密度均集中在250~300kg/m^(3),平均热导率在0.25~0.30W/(m·K)之间,整体呈现先上升后稳定的趋势。研究结论可为风冷冰箱换热器的优化设计提供理论支撑。
In order to solve the problems of reduced air flow area,increased heat transfer resistance,and higher refrigerator energy consumption caused by frosting on the evaporator surface,a frosting test platform for evaporators with vertical air ducts was built,and an experimental study was conducted on the distribution characteristics of the frost layer on the evaporator surface along the air flow direction.The frost layer thickness at different times was measured in zones using a timed imaging device,and the average density and average thermal conductivity of the frost layer on the evaporator surface were calculated.The experimental results show that when the inlet coolant temperature is decreased from-15℃to-20℃,the difference in blockage rate between Zone 4 and Zone 5 is only 8%,and a lower cold surface temperature is beneficial to the uniform distribution of the frost layer.When the relative humidity increases from 75%to 85%,the average blockage rate increases by 9.4%~55.7%.An increase in relative humidity significantly promotes the growth of the frost layer.Based on the three stages of flat-plate frosting,the changes in thermal conductivity and frost layer density over time are divided into three stages:rapid growth period,uniform growth period,and stable period.In the late frosting period,the average density is concentrated in the range of 250~300 kg/m^(3),and the average thermal conductivity is in the range of 0.25~0.30 W/(m·K),with an overall trend of first increasing and then stabilizing.The research conclusions can provide theoretical support for the optimal design of heat exchangers in air-cooled refrigerators.
作者
孙藤翡
晏刚
陈旗
SUN Tengfei;YAN Gang;CHEN Qi(School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《流体机械》
2025年第8期1-9,26,共10页
Fluid Machinery
基金
国家自然科学基金项目(52006165)。
关键词
风冷冰箱
蒸发器结霜
霜层分布
换热特性
霜层物性参数
霜堵
air-cooled refrigerator
evaporator frosting
frost distribution
heat transfer characteristics
frost physical parameters
frost blockage
作者简介
孙藤翡(1998),女,硕士研究生,研究方向为冰箱蒸发器结霜实验及仿真,E-mail:s1256879467@163.com;通信作者:陈旗(1990),男,博士,副教授,研究方向为制冷与空调节能新技术及热泵技术等,通信地址:710049陕西省西安市碑林区咸宁西路28号西安交通大学能源与动力工程学院,E-mail:qichen@mail.xjtu.edu.cn。
