基于CFD模拟的单点系泊船型网箱浮架结构分析与设计

Structural analysis and design of single point mooring cage floating frame based on CFD simulation

针对单点系泊(SPM)网箱系泊力大于传统网箱,离岸环境承受风浪时风险更高的问题,研究设计了一种相较传统圆形网箱拥有更小系泊力的船型网箱,运用正交原理制定了三因素三水平的试验方案,对网箱浮架进行了计算机数值模拟,分析网箱在波流共同作用下的水动力特性变化。研究表明,在兼顾经济成本与网箱安全性的条件下,长24 m,宽9 m,头部角度为60°的网箱浮架具有较优良的水动力性能和相对较低的养殖成本。该网箱系统能随着潮流改变方向而在锚点周围移动,从而极大减小网箱底部的养殖残渣堆积并降低锚固安装成本,可为我国深水网箱的发展提供一定的理论参考依据。

The single point mooring(SPM)cage system has attracted considerable attention because of its ability to move around anchor points with the current in different directions.This mobility can considerably reduce the accumulation of aquaculture residue at the bottom of the cage and reduce the installation cost of anchorage.However,because the mooring force of the SPM cage is greater than that of a conventional circular cage,the risk of the SPM cage system is very high when exposed to wind and waves.A ship-type of a floating frame with a mooring force that was smaller than that of a conventional circular cage was designed to solve this problem along with a threefactor and three-level test scheme that was formulated based on the orthogonal principle.To analyze the changes of the hydrodynamic characteristics of the cage when exposed to both waves and current,computer numerical simulation of the cage floating frame was conducted.The results show that the stress of the cage will initially decrease followed by an increase that is caused by the length increasing when the width of the floating frame is constant.The stress of the cage will continue to amplify with the increase of the width of the floating frame and the angle of the head.Taking economic costs and cage safety into consideration,the analysis shows that a cage floating frame with a length of 24 m,a width of 9 m,and a head angle of 60°has excellent hydrodynamic performance and a relatively low breeding cost.This provides a solution to address to the risk faced by the SPM deep-water cage and provides a theoretical reference for developing deep-water cages in China.