寒区隧道地源热泵加热系统埋管间距优化分析

Pipe Distance Optimization of Geothermal Resource Heat Pump in Cold Region

为预防寒区隧道冻害问题,将地源热泵型供热系统应用于内蒙古博牙高速公路林场隧道中,用于对隧道洞口段衬砌和排水系统加热.采用有限元计算方法,首先通过对初始温度场的计算反演出岩体各项热物性参数,再以试验所得热交换管实际换热量作为模型中管壁的内边界条件进行热交换管的岩土热响应分析.计算结果显示,隧道内热交换管管壁温度及管间温度与现场试验结果能够很好地吻合,满足工程精度要求.利用验证后的有限元计算模型对热交换管间距进行优化,得到埋管最优间距为0.5～0.8m.

In order to prevent freezing damage to tunnels in cold regions, tunnel heating system with geothermal resource heat pump was introduced for the first time at Linchang tunnel in Inner Mongolia Autonomous Region of China. Finite element method （FEM）was employed to analyze the process of heat exchange. First, the thermal properties of rock mass was inverted by calculating initial temperature field. Then, a heat flow function was obtained which is fitted with the heat flow calculated by the experiment data, and a transient heating analysis was made. A comparison between the numerical and experiment temperature proves that the accuracy requirement can be met. Finally, the distance between pipes was optimized by this method, and the most economic distance between pipes ranges from 0.5 to 0.8 m.