水源热泵系统中地下水流贯通及其对温度场的影响

利用含水层储能的一般特点,提出流贯通;分析流贯通和热贯通的相互作用、相互影响及对工程实际的意义;并基于地下水水热运移的基本原理,建立地下水流动和热量输运的耦合数值模型。在此基础上对沈阳某场地水源热泵工程的运行进行流场及温度场的数值模拟分析,给出产生流贯通的依据,即利用水力坡度定量的判断流贯通发生与否;当水力坡度变化非常小、可忽略不计时,认为含水层出现流贯通;进而研究抽、灌量对流贯通的影响,发现抽、灌量越大,则出现流贯通时间越短;而大量的抽、灌量更容易发生流贯通,进而会引起热贯通的发生。在实际工程中可降低抽、灌水量,在条件许可的情况下可提高抽、灌井的间距,并可在抽、灌井运行一个周期后调整抽灌井位置,以减少热贯通的发生。

Groundwater Flow Transfixion of Groundwater Source Heat Pump System and Its Influence on Temperature Field

A new concept of flow transfixion is suggested by analyzing the general features of aquifer.The interaction between flow transfixion and heat transfixion,and its significance to practical engineering are also analyzed.A couple numerical model of groundwater flow and heat transferring is established based on the basic of water-heat transferring in the aquifer.And then numerical analysis of the flow field and the temperature field for one GSHP in Shenyang City shows that the formation of flow transfixion is hydraulic gradient,namely,it can be judged quantitatively by whether the flow transfixion takes place or not according to hydraulic gradient.When the hydraulic gradient has no notable change,the flow transfixion takes place.Furthermore,the effect of the injecting and pumping rate(Q) to the flow transfixion shows that the shorter of occurrence time of flow transfixion,the more of the value of Q,and it is easier to occur flow transfixion for more of Q,and then to lead to occurrence of heat transfi-xion.In practical engineering the occurrence of heat transfixion can be reduced by reducing the value of Q,by increasing spacing of injecting and pumping wells,and by rectifying position of the injecting and pumping wells after a work cycle.