磁性冷表面结冰抑霜的可视化研究

Visualization study of freezing and frost suppression on magnetic cold surface

通过在自然对流条件下,研究磁性冷表面上的结冰结霜现象以及不同冷面温度下磁场强度对结冰速度,霜晶形态的影响规律。实验发现磁性表面上水滴的冻结,霜晶的形态与非磁表面是完全不同的。表磁为250 mT的磁性表面水滴的冻结时间较非磁性表面相比明显延长。不同冷面温度下的水滴冻结时间与磁场强度呈多极值关系。即在一定环境条件下,存在延迟冰晶冻结的最佳磁场强度。当场强超过一定值时,磁场反而会加速冰晶的冻结,且水蒸气在不同表磁的磁性表面上凝结、冻结时的液滴形状也不相同。最后从理论上分析了这些现象产生的原因。

Under natural convection conditions,the icing and frosting phenomenon on the magnetic cold surface and the influence of the magnetic field strength on the icing speed and the frost crystal shape under different cold surface temperatures were studied.It is found by experiments that the freezing of water droplets on magnetic surfaces and the morphology of frost crystals are completely different from those on non-magnetic surfaces.The freezing time of water droplets on a magnetic surface with a surface magnetism of 250 mT is significantly longer than that of a non-magnetic surface.The freezing time of water droplets under different cold surface temperatures has a multi-extreme relationship with the magnetic field intensity.That is,under certain environmental conditions,there is an optimal magnetic field strength for delaying ice crystal freezing.When the field strength exceeds a certain value,the magnetic field will accelerate the freezing of ice crystals instead.In addition,the shape of the droplets when water vapor condenses and freezes on the magnetic surfaces of different magnetic surfaces is also different.Finally the causes of these phenomena was theoretically analyzed.