浅层竖直螺旋地埋管换热器传热特性实验研究
Experimental study on heat transfer characteristics of shallow vertical spiral buried pipe heat exchangers
摘要：
搭建了浅层竖直螺旋地埋管换热器的原型尺度实验平台,对不同管内流速、降雨入渗影响下螺旋地埋管的传热特性进行了实验研究,引入瞬时传热系数、效能系数2个定量评价指标来反映螺旋地埋管的传热特性。结果显示:增大管内流速可提升螺旋地埋管的传热性能,但当流速增大到一定程度时,由于换热不充分,对地埋管传热性能的提升效果逐步减弱,同时还会增加系统水泵的能耗,所以建议螺旋地埋管的设计流速在保证湍流的前提下不宜过高;降雨入渗可在一定程度上提升螺旋地埋管区域土壤的热物性,更有利于热量的传递,可有效提升螺旋地埋管的瞬时传热系数和效能系数,从而强化地埋管换热性能。
Abstract：
A prototype-scale experimental platform for a shallow vertical spiral buried pipe heat exchanger is built to conduct experimental studies on the heat transfer characteristics of the spiral buried pipe under the influence of different flow rates in the pipe and rainfall infiltration. Two quantitative evaluation indexes of instantaneous heat transfer coefficient and efficiency coefficient are introduced to reflect the heat transfer characteristics of the spiral buried pipe. The results show that increasing the flow rate in the pipe can improve the heat transfer performance of the spiral buried pipe. However, when the flow rate increases to a certain extent, due to insufficient heat exchange, the improvement effect on the heat transfer performance of the buried pipe will gradually weaken, and the energy consumption of the system pump is also increased.Therefore, it is recommended that the design flow rate of the spiral buried pipe should not be too high on the premise of ensuring turbulent flow. Rainfall infiltration can improve the thermal properties of the soil in the spiral buried pipe area to a certain extent, which is more conducive to heat transfer, and can effectively improve the instantaneous heat transfer coefficient and efficiency coefficient of the spiral buried pipe, thus improving the heat exchange performance of the buried pipe.
Keywords:spiral buried pipe heat exchanger; heat transfer characteristic; flow rate in pipe; rainfall infiltration; instantaneous heat transfer coefficient; efficiency coefficient; prototype experiment