Stress-Generated Ice Crystals in a Nearly Isothermal Two-Phase System
Stress-Generated Ice Crystals in a Nearly Isothermal Two-Phase System
复制标题
近等温两相系统中应力产生的冰晶
DOI：
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发表时间：
1968
影响因子：
3.4
通讯作者：
E. Lachapelle
中科院分区：
文献类型：
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作者：
E. Lachapelle
利用冰-水两相系统来说明流体静力和非流体静力应力对平衡的影响，是热力学理论史上一个反复出现的主题。静水压力对冰熔点的影响已得到理论和实验的证实。非流体静力的压力在今天仍然是一个有争议的话题；一些理论学家预测，在这样的压力下，冰会重新结晶，但熔点下降的幅度尚不确定。冰的再结晶是由流体静力的局部变化引起的，早在一个世纪以前就被预测和实验证实了。温带冰川深处的洞穴为后一种现象的发生提供了合适的环境。在美国华盛顿州的蓝色冰川中，有一个充满水的洞穴，与一条几乎静止的冰的隧道相交，里面排列着巨大而不寻常的单晶，这些单晶显然是由于静水应力的影响而形成的。即使这个空腔周围压力熔点的微小差异也足以消除其中冰形成时的熔化热。有证据表明，周围冰中融水的间隙运动也有助于热量和质量的传递。这些晶体的形式表明它们生长在略过冷的水中。这表明，这种生长模式是由腔壁上定向应力的存在所维持的。
The use of the two-phase system ice–water to illustrate the effects on equilibrium of both hydrostatic and non-hydrostatic stresses has been a recurrent theme in the history of thermodynamic theory. The effects of hydrostatic pressure on the melting point of ice are firmly established by theory and experiment. Those of non-hydrostatic stress are still a subject of debate today; several theorists have predicted ice re-crystallization under such stress, but the magnitude of any slight melting-point depression is not known with certainty. The recrystallization of ice caused by local variations in hydrostatic stress was predicted and experimentally confirmed over a century ago. Cavities deep within temperate glaciers provide a suitable environment for the occurrence of this latter phenomenon. A water-filled cavity intersected by a tunnel in nearly stagnant ice of the Blue Glacier, Washington State, U.S.A., was lined with large and unusual single ice crystals which apparently owe their origin to the effects of hydrostatic stress. Even the minute differences in pressure melting point around this cavity are adequate to remove the heat of fusion as ice forms within it. There is evidence that interstitial movement of melt water in the surrounding ice also contributes to the heat and mass transfer. The form of these crystals indicates that they grew into slightly supercooled water. It is suggested that this growth pattern is sustained by the existence of oriented stresses at the cavity walls.