人工地下水流场提高地埋管换热性能分析与模拟:以福建某地区为例

Analysis and Simulation of Heat Transfer Performance of Buried Pipe Banks Under Artificial Flow Field:Taking an Area in Fujian Province as an Example

我国南部的气候冬暖夏热,地埋管式群管换热器夏季和冬季所释放或吸收的热量无法达到均衡,运行期间造成的累热效应对地温场的影响不容忽视。针对这个问题,在得出地埋管系统最优设计参数的基础上,提出在换热管附近施加人工流场的优化方案。结合实际工况,利用数值法对优化前后地埋管周围地温场的变化特征进行了水热耦合模拟,对累热效应的影响程度和人工流场的优化效果进行了验证。结果显示,优化前,地埋管运行20a后岩土体的平均温度相对初始地温上升了22.05%,地埋管对地温的影响范围有扩大趋势,受地下水流向的作用存在热迁移现象;优化后,地埋管附近平均地温的上升幅度较优化前降低了46%,温度羽也被人工流场束缚于抽水井附近相对较小的区域,没有引起大面积的地温抬升现象。因此这种设置人工流场以缓解累热效应的方法可在适宜地区进行推广。

In the hot summer and warm winter area of south China,the quantity of heat releasing in hot weather and absorbing in cold cannot achieve equilibrium.Thus the thermal incubation effect induced by this should not be negligible.To solve this problem,an optimization is proposed to set up artificial flow field around buried pipes based on the optimal design parameters.For this purpose,the numerical method was used to simulate variation characteristics of geothermal field under actual conditions,and validate influence of thermal effect as well as optimization effect of artificial flow.The result shows that before the optimization the mean temperature around the buried pipe rises by 22.05%in relation to its initial temperature after the pipe′s operation for 20 years with a tendency to expand its effect on the ground temperature and cause the heat transfer fue to the ground water flow direction.In contrast,after optimizing design scheme by setting wells near pipes,the rise of mean temperatures has decreased by 46% and the heat plume is also trapped in a relatively small area near the pumping well.Thus this method can be promoted in appropriate areas.