U型地埋管换热器的传热性能数值模拟-《郑州大学学报(工学版)》

文章信息/Info

Title:: Numerical SimulationofHeatTransferPerformance ofUGround-TubeHeatExchangers

Author(s):: WUJin．xin91; LIJun．cha01; PANYan．kail; XU Kel; WANGZhi．jie2; WU Yan．bin92; 1.School of ChemicalEngineeringand Energy，ZhengzhouUniversity，Zhengzhou450001，China；2．Zhengzhou Institute ofAutomation，Zhengzhou450003，China

Keywords:: roundsource heat pump; heatexchanger; U—tubeground tube; thermalinterference; thermal insulating layer; numerical simulation

摘要:: 针对土壤源热泵系统中单、双U型地埋管换热器的传热问题,建立三维几何模型,用FLUENT软件进行模拟计算,在相同工况下对比分析了钻井深度、流体速度、保温层等对单、双U型埋管换热器的单位井深换热量、流体出口温度及热短路的影响.结果表明,双U型埋管换热器的单井换热量比单U型增加30％以上;无保温层时,双U型埋管换热器的热短路问题较严重;出口管外敷设保温层可有效减小热短路的影响,使单、双U型管换热器单井换热量均增加15％以上,且双U型埋管换热器的综合性能更优;保温层的最佳长度约为120 m.

Abstract:: A three—dimensional geometric model of single—U，double·U ground-tube heat exchangers and sur· rounding soil wasestablished in ground source heatPumpsystem．The effects ofdifferentborehole depth，flow velocity andthermal insulating layer on the heat exchanging quantity per well·-depth were researched by FLU·· ENT software．The temperature difference between the inlet and the outlet，theheat exchanging quantity per well．-depth and the thermal interference aboutsingle-U and double-U ground-tube heat exchangers were eom—· pared under the sameconditions．The resultsshow that the heat exchanging quantity perwell-depth ofdouble— Uground—tube heat exchangers increases 30％ormore，but their thethermal interference is more serious without thermal insulating layer．The influence of thermal interference can be reduced by the thermal insulating layer，which makesthe heat exchangingquantity per well—depth increase more than 15％，andcomprehensive performance of the double—U ground—tube wassuperior to single-U．The optimum length of the thermal insula— ring layer is 120 meters．