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Study of Melting of Snow Layr with a Combined Effect of Temperature and Concentration

温度和浓度联合影响下雪层融化的研究

基本信息

批准号：
06650228
负责人：
SUGAWARA Masahiro
金额：
$ 1.15万
依托单位：
AKITA 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

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650228/
关键词：
Snow Melting Aqueous solution Concentration Diffusion 雪層濃度拡散

项目摘要

When a snow layr is quickly immersed in a binary aqueous solution, the snow melts with a temperature fall in the melting system, even when there is initially no temperature difference between the snow layr and the aqueous solution. Experiment of the melting of snow is conducted by using two kinds of aqueous solutions of calcium chloride and propylene grycol. Temperature of the solutions are 0,10,20degree C higher than the snow temperature at the beginning of the melting. The higher temperature of the solutions melts much more snow compared with the lower temperature solutions.It is impossible to predict the melting manner by only using a cell and diffusion controlled model for the same temperature between snow and solution due to the higher temperature solution than the snow. To overcome this difficulty, it is assumed that the snow melts according to the two process due to the high Lewis number. After snow melts with a driving force of the temperature difference between snow and solution, the melting subsequently begins controlled with the diffusion of concentration. The period in the first process is very small as about 0.04 seconds. On the other hands, the period in the second is very long as about 4 seconds. Although the melting manner is strongly dependent on the thickness of the diffusion layr, the thickness near the 0.03mm in the Nernst model predicts well the abrupt temperature depression in the melting system and the melting amount. It is demonstrated that the maximum melting amount is largely affected by the temperature of solutions, concentration, and porosity of snow. The special temperature difference is defined for the calculation of the maximum melting amount that is strongly dependent on the conditions of the melting.

当雪层快速浸入二元水溶液中时，雪随着融化系统中的温度下降而融化，即使在雪层和水溶液之间最初没有温差时也是如此。用氯化钙和丙二醇两种水溶液进行了融雪实验。溶液的温度比融化开始时的雪温度高0、10、20 ℃。溶液的温度越高，融化的雪量越大，由于溶液的温度高于雪的温度，因此在相同的温度下，仅用胞元和扩散控制模型是无法预测雪的融化方式的。为了克服这个困难，假设雪融化根据两个过程，由于高刘易斯数。在雪和溶液之间的温差的驱动力下，雪融化之后，融化随后开始受浓度扩散的控制。第一过程中的周期非常小，约为0.04秒。另一方面，秒中的周期非常长，约为4秒。虽然熔化方式强烈地依赖于扩散层的厚度，但Nernst模型中的0.03mm附近的厚度很好地预测了熔化系统中的突然温度下降和熔化量。结果表明，最大融化量在很大程度上受溶液温度、浓度和雪的孔隙度的影响。特殊的温度差被定义用于计算最大熔化量，该最大熔化量强烈依赖于熔化条件。