寒区冻结工程利用自然冷能的空冷换热技术研究

Study on Air-Cooled Heat Exchanging Technology with Natural Cold Energy for Ground Freezing Project in Cold Region

西北地区冬季有着充沛的自然冷能。为了有效利用这种自然冷能进行井筒冻结,设计了翅片管式盐水空冷换热器;并在低温冷库内,进行了盐水空冷换热试验。结果表明:降低气温,可大幅提升空冷换热效果;增加空气及盐水流量,可小幅提升空冷换热效率。为评价空冷盐水的工程实用性,以地处锡林郭勒盟的鲁新煤矿主井井筒冻结工程为背景,对3种温度状态盐水形成的冻结壁温度场进行了数值模拟,结果表明:在相同孔间距下,准低温(-10^-15℃)盐水冻结壁交圈时间为人工制冷盐水的1.5~2倍,约占当地冬季时间的1/2;适度缩小孔间距后,冻结壁交圈时间与正常孔间距下的人工制冷盐水交圈时间相当。试验及数值模拟表明:寒区可以利用盐水空冷换热技术,开发利用自然环境冷能来进行井筒冻结。

In North-West China,there was sufficient natural cold energy in winter.In order to effectively utilize the natural cold energy for the mine shaft freezing,a fin tube type brine air cooled heat exchanger was designed.A brine air cooled heat exchanging experiment was conducted in a low temperature cold storage.The results showed that the cooled air temperature could highly improve the air cooled heat exchanging effect.The air and brine flow increased could lowly improve the air cooled heat exchanging rate.In order to evaluate the engineering practices of the air cooled brine,based on a mine main shaft freezing project of Luxin Mine in Xilingele League as a background,the numerical simulations were conducted on the temperature field of the freezing wall formed with three different temperature brines.The results showed that under the same borehole spacing,the connection time of the freezing walls formed with the quasi-low temperature（-10- -15℃）brines was 1.5-2times of the artificial refrigerated brine and would be 1/2of the local winter time.After the borehole spacing properly reduced,the freezing wall connection time would be equal to the connection time of the artificial refrigeration brine under the normal borehole spacing.The experiment and numerical simulation showed that with the utilization of the brine air cooled heat exchanging technology,the development and utilization of the natural environment cold energy could be applied to the mine shaft freezing.