寒区土壤源热泵换热埋管的水热力耦合分析

为解决寒区土壤源热泵地下埋管冻胀安全性问题,根据传热学、渗流和冻土力学理论建立寒区土壤源热泵水热力耦合的数学力学模型及其控制方程。利用FEPG有限元自动生成软件,对大庆油田某土壤源热泵地下埋管所在土体内温度场分布、冻胀位移及应力作用进行仿真计算,并对不同深度、不同回填区土壤导热系数、不同管脚间距情况进行了对比分析。结果表明,土壤源热泵运行初期,土壤未冻结,埋管的位移量很小。土壤温度达到相变温度后,土体冻结体积增大,埋管发生挤压变形。当土壤温度超过冻结相变区（-0.75℃,-0.30℃）时,埋管不会发生连续不断的变形。

Thermal Dynamic Analysis of Buried Hent Exchanger in Ground-source Heat Pump System in Cold Region

In order to solve the frost-heaving safety problems of buried heat exchanger hydronic in ground-source heat pump,a mathematics mode1 and its contro1 equation were put forward according to heat transfer,filtration theory and mechanics of frozen soil,which is the couplings problem of temperature field,hydronic field and stress field.The temperature field,frost heaving displacement and stress distribution of ground-source heat pump in Daqing oilfield were simulated with finite elements method.The contrast and analyses are carried out according to the different soil depth,the different soil thermal conductivity in backfilled areas,the different spacing of tube foot.The results showed that the least temperature and heat affected zone in soil increases gradually with operating time.At the beginning of operation,the displacement of buried heat exchanger is small because the soil is not frozen.When the soil temperature reaches the phase temperature,soil volume increases in size,and then buried tube deforms.When soil temperature exceeds between-0.75℃ and-0.30℃,buried tube doesn＇t deform.