水平地埋管冬季土壤温度场及换热性能研究

Study on Soil Temperature Field around Horizontal Buried Pipe and Its Heat Exchange Performance in Winter

以土壤源热泵水平地埋管为研究对象,建立了水平地埋管的二维数学模型,采用边界离散、保形变换方法对模型进行求解,采用VB编制了水平地埋管及其周围土壤温度场计算软件。运用模型和软件,模拟冬季工况下,水平地埋管及其周围土壤温度场和热流量分布情况。冬季水平地埋管周围土壤温度纵向呈不对称单峰状分布,横向呈完全对称的单峰状分布。地埋管外土壤沿与地埋管同圆心的圆周上温度呈正弦曲线分布。随着位置远离地埋管,土壤温度变化幅度减小。地埋管上部热流量较高,下部热流量较低。给定工况下水平地埋管单位管长换热量模拟值与实验值比较,误差为6.2%,可靠性较高。

Taking the horizontal buried pipe for ground-source heat pump as research object, a two-dimensional mathematical model is established and solved by the boundary dispersion and conformal mapping methods. The calculation software of temperature field of the horizontal buried pipe and its surrounding soil is programmed by Visual Basic. The temperature field and heat flow rate distribution of the horizontal buried pipe and surrounding soil in winter are simulated by the model and software. The soil temperature around the buried pipe shows a single-peak asymmetric profile in vertical direction and a single-peak symmetric profile in horizontal direction. The temperature on the outer surface of the buried pipe and on the concentric circle around the buried pipe shows a sinusoidal profile. The variation of soil temperature decreases with increasing distance from the buried pipe. The heat flow rate through the upper part of the buried pipe is higher, and that through the lower part of the buried pipe is lower. When the simulated value and experimental value of heat exchange quantity per unit length of the buried pipe are compared under given regime, the error is 6.2%, with higher reliability.