埋管换热器对地表温度影响的模拟分析

Simulational analysis of effect of buried tube heat exchanger on land surface temperature

为探讨地源热泵系统垂直埋管换热器运行对地表温度的影响,采用数值模拟的方法,基于一定的覆土厚度,结合不同工况下的埋管负荷,建立了地下土壤、钻孔、覆土与外界环境之间的传热模型,对埋管运行期覆土层温度场的变化进行了分析,并对地表温度随覆土厚度的变化规律进行了研究。结果表明,在地埋管的连续换热作用下,埋管周围土壤温度显著变化,且越接近钻孔中心,温度变化幅度越大;钻孔顶部覆土层温度局部变化,随着覆土厚度增加,温差递减;地表温度变化范围及上升幅度与埋管换热量成正比,与覆土厚度成反比;增加覆土层厚度能有效减缓地埋管换热对地表温度造成的热影响,有利于管群区域的红外伪装。

To discuss the effects of land surface temperature with vertical buried pipe heat exchanger,heat model of under soil, borehole, cover soil and external environment was established by numerical simulation based on the thickness of cover soil,the temperature variation of cover soil in run-time is analyzed,and the temperature variation of land surface with thickness of cover soil discussed. The results show that with the system being operated continu-ously,the soil temperature around the pipe changes significantly,and the closer to the drilling center,the higher the temperature changes. At the top of the hole,the temperature of cover soil changes,and with the increasing of the thickness of cover soil, the temperature decreases. The range of variation and the ascensional range of land surface temperature are proportional to the heat exchange capacity,and inversely proportional to the thickness of cover soil. Increasing the thickness of cover soil could effectively lower the effect of buried tube heat transfer on land surface temperature. It would help to avoid the infrared exposure of pipes.