基于正交试验设计的盘球附体抑涡试验研究

Experimental Research on the Disc-ball Attachment for Suppressing Vortex-induced Vibration

为探究盘球附体尺寸和布置形式对海洋立管涡激振动的影响,对盘球附体这一新型海洋立管涡激振动抑制装置进行了试验研究。考虑盘球附体布置的螺距、螺纹数、盘球附体直径及1个螺距内的盘球数量等4个因素,每个因素设计了3种水平。采用正交试验设计法生成了9组立管试验模型,测量了9组立管模型的横流向应变RMS值、顺流向应变平均值以及横流向振动频率,并将这些结果与不带附体的裸管模型试验结果进行比较。研究结果表明,合理布置的盘球附体能够降低立管模型横流向应变RMS值和频率,但不会增加阻力。利用正交试验表评判了盘球附体布置的各因素对涡激振动横向振幅的影响,发现螺距是影响盘球附体抑涡效果最重要的因素,当螺距较小、1个螺距内盘球的数量较多时,盘球附体可能达到较好的抑涡效果。研究结果可为盘球附体优化设计及提高盘球涡激抑制效果提供一定的参考。

In order to investigate the effect of the size and layout of the disc-ball attachment,a new device used to suppress the vortex-induced vibration of the marine riser,an experimental study was conducted on four factors including pitch,number of threads,diameter of the disc-ball attachment and number of disc balls in one pitch,and each factor was designed for three levels.The orthogonal experimental design method was used to produce nine riser experimental models.The RMS value of cross-flow strain,the mean value of down-flow strain and the cross-flow vibrating frequency were measured,and these results were compared with those without an attachment.The results show that the reasonable arrangement of the disc-ball attachment can reduce the RMS value and frequency of the cross-flow strain of the riser model,but it will not increase the resistance.An orthogonal experiment table was used to evaluate the influence of the factors on the lateral amplitude of vortex-induced vibration.It is found the pitch is the most influential.When it is small,and there are many disc balls in a pitch,the vortex-induced vibration can be effectively suppressed.The research results can provide a certain reference for the optimal design of the disc-ball attachment and the enhancement of vortex suppression.