【作者】 黄俊惠；

【导师】 时晓燕； 唐志伟；

【作者基本信息】 中国农业大学 ， 农业水土工程， 2005， 硕士

【摘要】 本文通过总结地源热泵地下换热器传热模型的研究现状,指出由于U型管特殊的物理尺寸以及土壤物理特性的特殊性,致使现在仍没有准确描述其传热特性的三维数学模型。根据这种现状,文章提出了通过改进和耦合现有的在不同方向上的低维传热模型来建立描述U型管地下换热器传热的准三维传热模型,并模拟了U型竖直埋管地下换热器在各种运行工况下的传热特性。这对于全面、准确的描述U型管地下换热器的传热特性,进而为地源热泵系统的设计都有一定的参考价值。 区别于现有的传热模型边界条件的处理方式,该模型在换热器进水口的边界处引入换热功率函数作为边界条件,提出简化单个线热源到区域中心距离的计算方法,运用有限体积法求解。模拟结果通过与实验的比较,说明该模型所得结果可以满足工程精度的要求,提高了计算精度,降低了模型响应时间。 本文给出运用该模型模拟可以得到的某时刻U型管周围各层土壤的温度分布和U型管内流体的温度分布情况以及U型管进出口温度随时间的变化情况,最后还讨论了如管的物理尺寸、土壤热性能等影响U型管地下换热器传热的各种因素。更多还原

【Abstract】 After reviewing of current articles about Ground Heat Exchanger (GHE) used in Ground Source Heat Pump (GSHP) system, the absence of 3-D model of GHE heat transferring can be concluded. In order to simulate the behavior of the U-tube GHE used in GSHP system, a pseudo 3D model which was based on coupling two lower dimensional models was developed in this paper. It aimed to provide technical support to GHE design and installation.Different from the treatment of general boundary condition, a heat exchange power function was introduced as the boundary condition for the inlet of the U-tube for the first time, and distance between the heat source and the center of the field was simplified by calculating a mean distance between them. Finite-volume-method was used to solve the control equations. The comparison between numerical and experimental result confirmed the validity of the model. Accuracy and responsive ability were improved in this model.The ground temperature distribution around the U-tube, the temperature along the U-tube at a specific time can be achieved by this model. Lastly, the influent factors of heat transferring of the GHE were discussed with the model in the paper.更多还原