单向冷冻过程溶液中冰晶界面的竞争现象  

Competition phenomena of crystals in directional freezing of aqueous solutions

作　　者：马渊[1] 彭晓峰[1] 

机构地区：[1]清华大学热能工程系相变与界面传递现象实验室,北京100084

出　　处：《化工学报》2008年第11期2857-2863,共7页CIESC Journal

基　　金：国家自然科学基金重点项目(50636030)~~

摘　　要：通过对溶液冷冻过程冰晶界面发展变化的实验观察,定义了界面发展过程的3个阶段,分析各个阶段的现象特征,并从界面区浓度分布探析界面规则形态的物理本质。界面的发展过程中,会因为来自内部或者外界的扰动,使界面局部区域产生不均匀性,导致晶枝间的竞争现象,而决定这些竞争现象及冰晶生长的驱动因素是界面附近的过冷度分布。竞争现象机理的分析,有助于更清晰地了解生物材料在冷冻过程中的结冰特性。Experimental observations during freezing of aqueous sodium chloride solutions indicated that ice front development occurred in three periods.The concentration distribution near the interface was analyzed to understand the interfacial regular morphology.Both concentration and temperature profiles near the interfaces were greatly influenced by the disturbance inside or outside the zone,which induced the competition between crystals.The distribution of liquid sub-cooling played a critical role in the competition processes.The investigation of the competition phenomena is helpful to understanding the freezing characteristics of biological tissues.

关 键 词：水溶液 冷冻 显微可视化 界面 竞争 

分 类 号：TK124[动力工程及工程热物理—工程热物理]