摘要
为了优化换热器结构以提高其除霜性能,通过水平圆管结霜可视化实验台对受限空间内结霜过程进行了实验研究,分析了霜层厚度沿管长方向的生长规律、结霜量和热流量随时间的变化规律,以及湿空气初始流速、温度、相对湿度和管壁温度等因素对圆管表面结霜量和热流量的影响。实验结果表明:结霜初期,霜层厚度沿管长方向逐渐升高;之后,圆管中部的霜层最厚,靠近入口的霜层厚度最小;融霜最先发生于空气流道出口处;结霜量随时间延长呈现增长趋势,而热流量呈现先增大后减小的趋势;较高的湿空气流速、湿空气温度、相对湿度和较低的壁面温度对应较大的结霜量和热流量,其中管壁温度对结霜量和热流量影响相对较小。实验所获得的结霜特性与换热规律对换热器设计具有一定的参考价值。
An experimental study on the frosting process in a confined space through a horizontal tube frosting visualization test bed is conducted to optimize the structure of the heat exchanger and improve its defrosting performance.The growth rule of frost layer thickness along the length of a tube,the variations of frost accumulation and heat transfer rate with time are evaluated.The influences of wet air initial flow rate,temperature,relative humidity and wall temperature on the frost accumulation and heat transfer rate on the surface of the tube are analyzed.Experimental results show that the thickness of the frost layer gradually increases along the length of the tube at the beginning of frosting.Then,the frost layers are the thickest in the middle of the round tube,and the lowest near the inlet,respectively.Frosting begins at the outlet of the air flow passage.The frost accumulation shows an increasing trend with time passing,while the heat transfer rate increases first and then decreases.Higher wet air flow rate,wet air temperature and relative humidity and lower wall temperature correspond to larger amount of frosting and heat transfer rate,among which the wall temperature has less influence on the frost accumulation and heat transfer rate.The resulting characteristics of frosting and heat transfer rate have certain reference value for heat exchanger design.
作者
董晓俊
丁培
张蓓乐
陈小砖
赖天伟
侯予
DONG Xiaojun;DING Pei;ZHANG Beile;CHEN Xiaozhuan;LAI Tianwei;HOU Yu(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China;School of Mechanical and Power Engineering,Henan Polytechnic University,Jiaozuo,Henan 454000,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2020年第2期71-77,共7页
Journal of Xi'an Jiaotong University
基金
陕西高校青年创新团队资助项目
中央高校基本科研业务费专项资金资助项目(ND6J005)
关键词
结霜特性
受限空间
霜层厚度
热流量
圆管
换热性能
frosting characteristics
confined space
frost thickness
heat transfer rate
circular tube
heat transfer performance
