摘要
为解决制冷系统除霜技术存在的问题,介绍了利用高压静电场技术及扫频高压交流电场技术在制冷系统中除霜的机理及研究进展,基于电流体动力学理论分析了霜晶分别在自然生长以及受高压静电场影响两种情况下不同的生长特性、机理和高压静电场中影响霜沉积量的主要电场参数,以及影响扫频高压交流电场技术除霜效率和能耗的主要参数。研究表明:电压及电场极性对高压静电场除霜的效率影响显著,频宽及交流电场持续施加的时间则是影响扫频高压交流电场除霜效率及能耗的主要电场参数;扫频高压交流电场除霜技术相比于静电场除霜技术,在除霜效率上更高,但能耗上处于劣势。最后,从除霜效率及能耗角度出发,提出了进一步深入研究的方向。
On the basis of the electrohydrodynamic（EHD） theory,the development of high voltage technologies in refrigeration equipment defrosting and its mechanism were studied,including high voltage DC electric technology and sweeping frequency AC electric technology.The characteristics and mechanisms of the growth patterns of frost crystal with and without the influence of electric fields were described respectively.The key electrical parameters such as voltage and electric polarity were focused on to analyze their influences on frost mass accumulation under the DC electric fields.Meanwhile,the influences of those factors such as the range of sweeping frequency and the application duration of the AC electric fields on defrosting efficiency and power consumption under the AC electric fields were discussed.The main results show that the presence of DC or AC electric fields can greatly affect both the frost crystals growth pattern and mass accumulation on cold surfaces.The frost crystals are more numerous,thinner,and more fragile compared to crystals without the electric fields. Frost mass accumulation will decrease to a threshold voltage,and beyond that voltage,the mass accumulation will increase.For a negative polarity,the frost structure is thinner and the break-off frequency of ice column is more frequent than for a positive polarity.The natural break-off frequency is associated with the frost crystals shape,height and thickness distribution.Under AC electric field,if the applied AC frequency matches natural break-off frequency,the complete removal of the crystal from the cold surface can be achieved.Therefore, wider AC frequency range leads to more frost mass removal.Also,there is an optimum duration of sweeping AC electric field which is less than 1 minute.Application of AC electric field for longer times than the optimum values seems to be unnecessary.The power consumption of the AC technology is higher compared to the DC technology.However,the application time of AC electric field is shorter than that of DC electric field.Therefore,finding the optimum time of AC electric field application can improve the power consumption and efficiency of this technique for maximum frost control.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2007年第12期97-100,共4页
High Voltage Engineering
基金
福建省自然科学基金资助项目(E044003)
福建省教育厅科研项目(JA04232).~~
关键词
高压静电场
扫频高压交流电场
制冷设备
除霜
霜晶
电流体动力学
high voltage DC electric field
sweeping frequency AC electric field
refrigeration equipment
defrost
frost crystal
electrohydrodynamic
作者简介
郑捷庆1973-，男，博士，讲师，主要从事电流体动力学的理论与应用研究。E-mail：zhjieqing@126.com
