超长GIL管廊排热通风研究

Heat Exhaust Ventilation for Ultra-long GIL Tunnel

武汉谭鑫培路地下综合管廊GIL舱属于超长封闭的构筑物,排热通风问题成为该工程设计的控制性问题,特别是舱体与周围土体的传热问题。基于IDA隧道模拟软件建立GIL舱一维分析模型,对当前通风系统在夏季、冬季与过渡季节典型气候下的短期排热,以及1年、10年和30年考虑季节变化下的长期排热进行分析。短期分析结果表明,管廊坡度和温度梯度会降低某些区域的目标通风率,在设计中应引起重视。长期分析结果表明,舱内空气和壁面温度升高在运行的前5、6年最为显著,并在30年的剩余时间内保持稳定,舱壁与周围土体释放10%～40%的热量。基于计算流体力学软件OpenFOAM建立GIL舱三维节段模型,分析电缆和支架对舱内温度场与速度场的影响,揭示GIL舱内速度分布的不均匀性与烟囱效应对温度分布的影响。

The GIL chamber in the utility tunnel under Tanxinpei Road in Wuhan is an ultra-long closed structure. Heat exhaust ventilation is the controlling problem in engineering design for the project, especially the heat transfer between the tunnel and the surrounding soil in the long term. A one-dimensional model for the GIL chamber is established by using the IDA tunnel simulation software to analyze the short-term and long-term heat exhaust, respectively. The short-term heat exhaust is analyzed for the typical climate of summer/winter/transitional seasons and the long-term analysis is carried out under the seasonal changes in 1 year/ 10 years/ 30 years. The short-term analysis results indicate that the slope of the utility tunnel and the temperature gradient lead to lower ventilation efficiency in certain areas. The long-term analysis results show that the air temperature in the GIL chamber and the wall temperature rise most pronouncedly during the first 5-6 years of operation and remain stable for the remaining time within 30 years. It also is found that around 10%-40% of the heat is released to the surrounding soil. A three-dimensional model of the GIL chamber is established using the fluid mechanics-based program, OpenFOAM, for 3D simulation. The effects of cables and brackets on the temperature and velocity fields in the chamber are analyzed. The effect of non-uniformity of velocity distribution and the stack effect on the temperature distribution in the GIL chamber are revealed. The results can provide some reference for the design and specification revision of heat exhaust ventilation for similar utility tunnels in the future.