霜晶形态演变过程的实验观测

Experimental investigation on frost crystal dynamical behavior

利用显微可视化实验台,对水平冷板上霜层表面冰晶的形态演变过程进行研究,在霜层成熟期观察到一种冰晶"吞噬"现象。冰晶在周围冰晶正常生长的同时发生升华,并且升华过程从温度较低的根部开始。在冰晶升华过程中,有可能于根部生长出新冰晶,最终被新冰晶取代。局部温度场和浓度场的相互作用是产生这些冰晶竞争现象的主要原因。

Ice crystals formation was experimentally studied during frosting on a cold flat plate. An exceptional phenomenon, or ＂licked-up＂ among prismy crystals, was observed with the microscopic visualization technique. During the full growth stage of frost layer, the unusual sublimation started from the root of the prismy crystal together with the growth of other crystals nearby. Then a new crystal appeared at the root of the sublimating crystal which turned slender until vanished. The newcomer grew up fast and took the place of the former one finally. The coupling effect of interaction between temperature and concentration fields is proposed as the main cause of these processes.