考虑内部空腔的单箱多室轨道梁温度场数值模拟方法

Numerical Simulation Method of Single-box Multi-cell Guideway Thermal Field Considering Internal Cavities

磁浮交通系统的相关规范对轨道梁的温度变形有着极其严格的要求。目前已有的轨道梁温度场研究中,对混凝土箱梁内部空腔的边界条件大多进行简化处理,计算结果难以满足磁浮规范的精度要求。为解决这一问题,基于大跨度公路-磁浮合建桥的可能性,提出了考虑内部空腔作用的单箱多室轨道梁温度场的数值模拟方法。以湖南郴州赤石大桥为背景,建立了大气环境下由腔内空气与混凝土流固耦合传热的单箱四室轨道梁模型,并用COMSOL有限元软件进行数值分析。将数值模拟结果与实测温度数据进行对比,结果显示全域全时程最大相对误差仅为4.03%,表明提出的数值模拟方法可以用于轨道梁温度场分析;与简化模拟方法相比,该方法能够满足公路-磁浮合建桥的轨道梁的精度要求;研究明确了内部空腔对于轨道梁温度场的影响。

The relevant codes of the maglev transportation system provide extremely strict requirements on the thermal deformation of guideway.Depending on the existing studies about the thermal field of guideway,most of the boundary conditions of the cavities inside the concrete box girder are simplified,leading to results hard to meet the accuracy requirements of the codes.To solve this problem and considering the possibility of the long span combined highway and maglev bridge,a numerical simulation method for the thermal field of single-box multi-cell guideway considering the influence of internal cavities is proposed here.Taking the Chishi Bridge in Chenzhou,Hunan Province as the background,a single-box four-cell guideway model is established in which the air inside cavities and the concrete conducts fluid-structure interacting heat transfer under the atmospheric environment.The COMSOL finite elementsoftware is used for numerical analysis.By comparing the measured temperature data,the results show that the maximum relative error of the whole domain across the whole time history is only 4.03%.Therefore,the numerical simulation method proposed here can be used to analyze the thermal field of guideway.Compared with the simplified simulation method,the method mentioned here is able to satisfy the accuracy requirements for guideway of the combined highway and maglev bridge.The influence produced by the internal cavities on the thermal field of the guideway has been clarified.