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Promotion of frost elimination applying super high-tension in a series of pulses

在一系列脉冲中施加超高张力促进除霜

基本信息

批准号：
06650238
负责人：
KUMADA Masaya
金额：
$ 1.28万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

In order to promote the elimination and control against the growth of frost, it is examine to impress high voltage in a series of pulses.In the first place, the effect of electric field on the frost formation around a tube in the uniform flow is studied phenomenologically. The electric field is applied between the surface and the mesh electrode. Removing of the frost from the surface depends on the structure of frost. The expected result of the electric field were obtained in the separation region.In the second place, a NEOFLON-FEP thin film surface was used as a frosting surface. It could be expected that the frost may be removed from the surface more easily by applying the electric fields, because the bounding strength between the frost and surface becomes weaker than a copper surface was used as the frosting surface. The results reveal that the wettability of the surface is not affect the frosting weight process. However, frost height on a NEOFLON-FEP-film surface was formed lower than frost height on a copper surface.Charge of high voltage has a highly inhibitory action against the growth of frost because it increases the Maxwell's stress and promote the growth of needle-shaped frost due to the nonisotropic growth occured by ordering of proton. But, when pulse frequency is large and pulse width is small, even charge of super high tension took no recognizable effect to the isotropic growth of frost. They are important factors on the control against the growth frost utilizing electric field.

为了促进霜层的消除和抑制霜层的生长，本文研究了在一系列脉冲中施加高压的方法。首先，从唯象的角度研究了均匀流中电场对管周结霜的影响。在表面和网状电极之间施加电场。表面霜的去除取决于霜的结构。在分离区获得了预期的电场效果。其次，采用NEOFLON-FEP薄膜作为磨砂面。可以预期，通过施加电场可以更容易地从表面去除霜，因为霜和表面之间的结合强度变得比铜表面用作结霜表面更弱。结果表明，表面润湿性对结霜增重过程没有影响。而NEOFLON-FEP膜表面的霜层高度低于铜表面的霜层高度，高电压电荷对霜层的生长有很强的抑制作用，这是因为高电压电荷增加了麦克斯韦应力，促进了针状霜层的生长，这是由于质子有序化引起的各向异性生长。但是，当脉冲频率较大、脉冲宽度较小时，即使是超高压荷电对霜层的各向同性生长也没有明显的影响。它们是电场控制霜层生长的重要因素。