| 吴志伟,宋汉周.基于Lu 模型的浅部地温场与渗流场耦合研究[J].水利学报,2015,46(3): |
| 基于Lu 模型的浅部地温场与渗流场耦合研究 |
| Study on shallow geothermal field and seepage field coupling based on Lu model |
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| DOI： |
| 中文关键词: 温度场 渗流场 饱和-非饱和 Lu模型 数值模拟 |
| 英文关键词: temperature field seepage field saturated-unsaturated Lu model numerical simulation |
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| 摘要点击次数: 2574 |
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| 中文摘要: |
| 在浅埋地质体中开展温度示踪地下水运移或渗流热监测等技术研究时，浅部地温场是其背景温度场，热量运移过程涉及非饱和带。非饱和带的导热系数受含水量控制，为提高浅部地温场仿真模型的精度，采用Lu模型来表示导热系数与饱和度的定量关系，据此建立了考虑参数非均质性的饱和-非饱和渗流场与周期性地温场的耦合模型。通过修改COMSOL Multiphysics 软件的相关模块，实现了双场耦合模型的有限元求解。数值算例的计算结果表明，非饱和带的水分分布及导热性能在垂向上是非线性变化的，地表附近岩土体的饱和度较低，其热导性能较差，地表的温度波动特征在向下传递过程中受到阻滞。与常用的热参数计算方法进行比较分析，认为常用的体积平均模型不能有效评价低含水量非饱和介质的热传递特性，计算时会引入一定的误差，而指数模型与Lu模型的计算结果较为接近。 |
| 英文摘要: |
| Before implement the techniques involving temperature in the shallow area，e.g. temperature tracing， seepage monitoring by thermal， etc.， it is necessary to illustrate the feature of shallow geothermal field. Wherein， the heat transfer involves unsaturated zone. The thermal conductivity of unsaturated zone is controlled by water content. In order to improve the accuracy of simulation model， Lu model is adopted to represent the relationship between them quantitatively. Taking these factors into account， a transient saturated-unsaturated seepage filed and periodical temperature filed coupling model has been established， wherein the thermal parameters is non-homogeneous. The numerical simulation is accomplished by some modified modules built-in COMSOL Multiphysics software. The results of numerical case study show that moisture distribution and thermal conductivity of the unsaturated zone is non-linear changes in the vertical. At the surface area， the soil is drier， so the thermal conductivity parameter is small and this area will obstruct the surface temperature passing down. Through comparing several thermal parameters calculation methods， it is known that the volume average model will introduce some error because it cannot be effectively evaluated the heat transfer characteristics of non-saturated medium with low water content. However，the result of exponential model is closer to Lu model. |
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