垂直U型地埋管换热器性能的动态仿真

代兰花 肖瑶瑶

摘 要：本文基于圆柱内热源理论建立了垂直U型地埋管换热器的数学模型。在MATLAB软件中建立了垂直U型地埋管换热器的动态仿真平台。利用该仿真平台研究进口温度、进口流速、钻井深度、回填材料、土壤以及间歇运行时间比等因素对垂直U型地埋管换热器换热性能的影响规律。结果表明，在一定范围内提高进口温度可以提升垂直U型地埋管换热器的换热性能;当进口流速为0.4～0.6 m/s时，增大进口流速可以有效提升垂直U型地埋管换热器的换热量;钻井深度越深，钻孔总换热量增加明显，单位钻孔深度换热量略微减小;但随着运行时间的增加，回填材料导热系数对换热的影响逐渐降低;土壤的导热系数越大，垂直U型地埋管换热器的换热量越大;采用间歇运行的方式可以提升垂直U型地埋管换热器的换热性能。

关键词：垂直U型地埋管换热器;动态仿真;影响因素;换热性能

中图分类号：TU831.4 文献标识码：A 文章编号：1003-5168（2021）22-0104-06

Abstract： In this paper， a mathematical model of the vertical U-shaped borehole heat exchanger is established based on the theory of the heat source inside the cylinder. The dynamic simulation platform of the vertical U-shaped buried pipe heat exchanger is established in MATLAB software. The simulation platform is used to study the influence of factors such as inlet temperature， inlet flow rate， drilling depth， backfill material， soil， and intermittent operation time ratio on the heat transfer performance of the vertical U-shaped buried heat exchanger. The results show that increasing the inlet temperature within a certain range can improve the heat transfer performance of the vertical U-shaped borehole heat exchanger; when the inlet flow velocity is 0.4～0.6 m/s， increasing the inlet flow velocity can effectively increase the heat transfer of the vertical U-shaped borehole heat exchanger; the deeper the drilling depth， the increase in the total heat transfer of the borehole is obvious， and the heat transfer per unit depth of the borehole slightly decreases; however， as the operating time increases， the thermal conductivity of the backfill material gradually reduces its impact on heat transfer; the greater the thermal conductivity of the soil， the greater the heat transfer of the vertical U-shaped buried heat exchanger; the use of intermittent operation can improve the heat exchange performance of the vertical U-shaped borehole heat exchanger.

Keywords： vertical U-shaped boried pipe heat exchange;dynamic simulation;influencing factors;heat transfer performance

地源熱泵技术的重点是设计出高效的地埋管换热器，地埋管换热器直接影响了整个系统的效率。热量在地埋管换热器与土壤间的传递过程相当复杂，会受到许多因素的影响，如土壤的热物性、钻孔深度、钻孔回填材料、流体进口流速、流体进口温度等。

因为钻孔内外的传热过程不同，所以垂直U型地埋管换热器的模型可以分为钻孔内沿深度方向的一维传热模型和周围土壤沿深度和半径方向的二维传热模型[1]。垂直U型地埋管换热器的模型主要分为解析解模型和数值解模型。……