基于CFD的悬索桥主缆进气方式的优化研究

Research on Optimization of Main Cable Air Intake Mode of Suspension Bridge based on CFD

为防止悬索桥主缆腐蚀,除湿系统被广泛应用于悬索桥主缆腐蚀防护。针对除湿不同进气方式,基于计算流体动力学(Computational fluid dynamics, CFD)数值计算方法,建立了主缆均一态有限元模型,并采用试验方式验证了所建立模型的准确性,探讨了不同进气方式对主缆内部空气流动特性的影响机制,最后对主缆进气系统的布置方案进行了优化。结果表明,基于CFD方法可以有效模拟主缆空气流动压力损失,模拟结果与试验误差小于5%;进口索夹数量对主缆内压降与压力分布有较大的影响,当进口索夹数量较少时,压力损失较大,当索夹数量超过4个时,主缆内压降变低,且总体压力分布更加均匀,而压力呈现“峰峦”状分布;当索夹数量为5时,相比于等距进气方式,不等距进气方式可以在一定程度上优化主缆内压力分布与速度分布。

In order to prevent the corrosion of the main cable of the suspension bridge, the main cable dehumidification system is widely used in the dehumidification of the main cable of the suspension bridge. According to the different air intake modes of dehumidification, based on the computational fluid dynamics numerical calculation method, the homogeneous finite element model of the main cable is established, and the accuracy of the model is verified by experiments. Then, the influence mechanism of different air intake modes on the internal air flow characteristics of the main cable is discussed, and finally the layout scheme of the main cable air intake system is optimized. The results show that the air flow pressure loss of the main cable can be effectively simulated based on the CFD simulation, and the error between the simulation results and the experiment is less than 5%. The number of imported cable clamps has a significant impact on the pressure drop in the main cable, and the pressure loss is larger when the number of imported cable clamps is less. When the number of cable clamps exceeds 4, the pressure drop in the pipe becomes lower, and the overall pressure distribution is more uniform, while the pressure shows a “peak” distribution. When the number of cable clamps is 5, compared with equidistant air intake, the pressure and velocity distribution in the pipe can be optimized to some extent.