非饱和多孔介质回灌过程中热弥散度特性试验

Experimental Research on Thermal Dispersion Degree Properties of Unsaturated Porous Media during Recharge

目的为了解非饱和多孔介质热弥散度变化特性,掌握不同多孔介质的热弥散度,为地下水源热泵工程的模拟预测的参数选择提供科学依据,解决凭经验进行水源热泵工程布井的不足.方法通过建立水平土柱模型,应用一维非饱和砂土热量运移定解方程,在室内测取不同回灌温度条件下不同多孔介质的热弥散度.结果相同温度回灌条件下,中砂热弥散度最大,粗砂次之,细砂最小;同种多孔介质回灌条件下,热弥散度随回灌水温升高呈现上升趋势.结论对热泵工程进行模拟预测时,应充分考虑热弥散度变化的影响,根据不同地质的实测数据对经验热弥散度值加以修正,使得模拟预测更加准确,以免造成抽灌井间的"热贯通",影响地下水环境.

The paper aims to understand the characteristics degree, to master the thermal dispersion degree of different of unsaturated porous media thermal dispersion porous media, so it can provide a scientific basic for the choice of the parameters of the simulation and prediction in groundwater source heat pump works, to solve the lack of well spacing by experience in water source heat pump engineering. By establishing the hori- zontal soil column model, applying a one-dimensional unsaturated sand thermal transport definite solution of equation, we measured the thermal dispersion degree of different porous media in different recharge tempera- ture conditions indoor. The results show that, under the same recharge temperature condition, the thermal dif- fusion degree of medium sand is maximum, coarse sand followed, and the fine sand is the smallest; under the same porous medium of recharge condition, the thermal dispersion degree showed rising trend with the re- charge water temperature upward. Simulation and prediction in the heat pump works, it should take full ac- count of the impact of thermal dispersion degree change. Amend experience thermal dispersion value accord- ing to the different geological measured data, so that the simulation and prediction can be more accurately. So as not to create the ＂heat transfixion＂ phenomenon of pumping and irrigation wells, which impacted the groundwater environment.