综合管廊地埋管换热器的全年运行特性分析

Annual Operation Characteristic Analysis of Buried Pipe Heat Exchanger in Utility Tunnel

建立综合管廊地埋管换热器的二维非稳态传热数理模型,并以寒冷地区的城市西安为例,通过模拟计算得到管廊内地埋管埋设的管长和管间距的最优组合,即管间距为0.75m,管长为67m。采用最优间距和管长的组合对地埋管换热器进行了全年周期的模拟计算,得出结论如下:供冷期内,地埋管的单位管长换热量变化范围为170~210W/m,采暖期内,地埋管的单位管长换热量变化范围125~170W/m;管廊混凝土结构的顶板、侧壁及底板的温度变化趋势不一致,距离地面越近则受到地表气温的影响越大;全年运行过程中,有地埋管运行时管廊内空气的出口温度与无地埋管运行时的差值最大为1.3℃,可见地埋管在管廊壁面内长期运行时对管廊内空气温度造成的影响很小,且不会对管廊内的通风系统造成影响。

A two-dimensional unsteady heat transfer mathematical model of the buried pipe heat exchanger in utility tunnel is established.Taking Xi'an in cold area as an example,the optimal combination of the buried pipe length and the pipe spacing in utility tunnel is obtained by simulation calculation,that is,the pipe spacing is 0.75 m and the pipe length is 67 m.The result shows,during the cooling period,the change range of heat flux of unit pipe is 170-210 W/m,while the change range during the heating period is 125-170 W/m.The temperature variation trend of concrete roof,side wall and floor of concrete structure of utility tunnel is not consistent.The closer the concrete is to the ground,the greater the influence of surface temperature on concrete is.During the whole year's operation,the maximum difference between the outlet temperature of air in utility tunnel with buried pipes and that without buried pipes is 1.3 C,It turns out that the long-term operation of buried pipes in the concrete structure has little effect on the air temperature in utility tunnel,and has no effect on ventilation system in utility tunnel.