相变吊顶与隧道空气耦合传热模拟分析

Analysis on Coupled Heat Transfer of Phase Change Material Ceiling and Air in Tunnel

摘要:

在地铁隧道区间构建了相变吊顶,相变材料选择水合盐晶体CaCl2７·6H2O.将列车在运行中的散热简化成移动发热物体等热流散热过程,建立列车在区间内运动三维物理模型,模拟了短时间内构建相变吊顶区间温度场变化.建立了相变材料与区间空气温度耦合传热模型,并求解.其求解结果与三维模型模拟结果对比,验证了耦合模型有效性.采用耦合模型对长时间作用下相变材料吸热量以及隧道区间温度进行预测,结果显示,在模拟工况条件下相变吊顶可吸收56.9%列车散发的热量.

Abstract:

Phase change material (PCM) ceiling is constructed by hydrated salt CaCl2·6H2O in the underground railway tunnel.The heat dissipation of moving train is simplified as a moving heat source which generates equivalent heat.The 3D model of moving train is established to simulate numerically the dynamic range of the tunnel of the nonsteadystate thermal environment in short time.Coupled heat transfer model (CHT model) of PCM and air in the tunnel is established,in addition,solution is given and compared with that of the 3D model,which validates the CHTmodel.The CHTmodel is used to simulate the heat absorption of PCM and tunnel temperature in the long time,and the results show that the PCM ceiling can absorb 56.9% of the heat emitted by train under the simulated operating condition.