桩基螺旋埋管换热器的沿程换热特性

Heat exchange characteristics of spiral pile geothermal heat exchanger along flow direction

建立了桩基螺旋埋管换热器的三维数值传热模型,研究了流体沿程换热特性和岩土温度分布特性。结果表明:桩基螺旋埋管换热器沿流动方向有进口、回填料热短路、小温差及出口4个换热阶段,每个换热阶段具有相应的换热特性;进行优化设计时,需控制小温差换热阶段的长度,增加其他换热阶段的长度,以提高螺旋埋管换热器的整体换热能力。

Establishes a three dimensional heat transfer model for spiral pile geothermal heat exchanger, and investigates the heat exchange and temperature distribution characteristics of the fluid along flow direction. The results show that the spiral pile geothermal heat exchanger along the fluid flow direction has four heat exchanging phases., inlet of heat exchanger, grout thermal short-circuiting, small temperature difference and outlet of heat exchanger. Each phase has its corresponding heat transfer characteristics. Reducing the length of small temperature difference phase and increasing the length of the other phases will enhance the heat exchanging capacity of spiral geothermal heat exchanger.