液氮冻结温度场均匀性实验液氮冻结温度场均匀性实验

针对液氮冻结过程中存在温度场分布不均匀的现象,采取在供液铜管上分段打孔及改变打孔方式和位置的方法,设计了四种供液管改进方案,并对这四种方案进行了模拟实验,分别分析其冻结温度场的均匀性和冻土发展速度,同时将改进方案与传统供液方式进行对比。结果表明,改进方案优于传统方案;四种方案中尤以方案三的效果最好,其管壁温度分布最均匀,冻土发展均衡且发展速度较快,液氮消耗量较少。这一研究结果为进一步解决液氮冻结均匀性问题提供了新思路。

Experiment on uniformity of temperature field in liquid nitrogen freezing ,

Aimed at the asymmetrical distribution of temperature field in the process of liquid nitrogen freezing, this paper offers four types of improvement programs designed by drilling on the different parts of the liquid-supplying copper pipe for different mode of holes. The paper introduces the simulation experiment on these four improvement program, gives an analysis of the uniformity of temperature field and growth rate of frozen soil, and highlights the comparison between the improved programs and conventional liquid-supplying mode. The results show that the improved programs compare favourably with the conventional program and the 3th program proves to be the best, due to its most uniform temperature field, the fastest growth rate of frozen soil and the least liquid nitrogen consumption. This study provides a new method for the settlement of uniformity in liquid nitrogen freezing.