不同钢丝堆积态下悬索桥主缆除湿性能

主缆除湿系统是悬索桥主缆在设计过程中的重要环节,直接影响主缆在工作中的服役寿命.针对主缆实际形貌特点,基于计算流体动力学(computational fluid dynamics,CFD)数值计算方法,系统研究了主缆内不同钢丝堆积态对主缆内部空气流动特性的影响,并通过南沙大桥(虎门二桥)实桥试验对数值计算结果进行验证.结果表明:通过数值模拟得到均一态的压降和试验实测压降的相对误差低于5％,表明所建立模型的准确性.松散态结构的存在会有效改变缆内横截面上的速度分布,在0.03倍直径处双堆积态下各个孔隙率下的速度增加率达到最大值,相较于单一堆积态缆内速度增加了12.9％;松散态堆积结构的松散程度对缆内的湍动能影响不明显,但是相比均一态堆积结构,双态堆积结构会使缆内的湍流变化更剧烈,湍动能峰值更大;不同孔隙率对于缆内内部的压降分布的影响不明显,相对于均一态在孔隙率为21.5时的双堆积态下最大压降仅减小了26 Pa.

Research on the Air Flow Characteristics of the Suspension Bridge Main Cable by Steel Wire Stacking States

The dehumidification system of the main cable is a significant component in the design process of main cable of suspension bridge, which directly affects the service life of the main cable. The influence of different steel wire stacking states in the main cable on the air flow characteristics inside the main cable was systematically studied based on the CFD numerical calculation method, and the actual bridge test of Nansha bridgre (Humen No.2 bridge) was carried out to verify the numerical calculation results. The test results demonstrate that the relative error between the homogeneous pressure drop obtained exploit numerical simulation and the measured pressure drop is less than 5%, indicating that the established model has acceptable accuracy. The existence of the loose structure can effiectively change the velocity distribution on the cross section of the tube. The velocity increase rate of each porosity reaches the maximum value at 0.03D in double stacking state, and the velocity in the cable increases by 12.9% compared with that in single stacking state. The looseness of the loose packing structure has no obvious effect on the turbulent kinetic energy in the tube, while the two-state stacking structure will make the turbulent energy in the tube change more dramatically and the peak value of the turbulent kinetic energy is larger compared with the homogeneous packing structure. Different porosity has no apparent effect on the pressure drop distribution inside the pipeline, Compared with the homogeneous states, the maximum pressure drop in the double stacking state at ? =24.5 is only reduced by 26Pa.