鱼类增殖放流站亲鱼池数值模拟研究

增殖放流是目前普遍采用的减缓水利水电工程对鱼类影响的措施之一。亲鱼培育是增殖放流的关键环节,亲鱼培育池是增殖放流站中的关键设施。鱼池不同流速流场区域的形成与亲鱼池的结构型式、工艺尺寸、进出水流量等多种因素有关,特别是针对国内山区急流河段水电工程鱼类增殖放流站亲鱼池的数值模拟研究还处于空白。采用计算流体力学(CFD)方法对亲鱼培育池流场进行了模拟,从亲鱼适宜流速区间最大化的角度,通过标准k-ε模型对最常用圆形和矩形两种不同结构型式的鱼池进行三维建模,分析比较了不同结构尺寸圆形池与矩形池的水力学条件,建议优先采用圆形池作为亲鱼培育池的型式,最适宜径深比为6∶1～3∶1;场地紧张而采用矩形池时,适宜长宽比为4∶1～2∶1。除流场外,温度、溶氧、排污分布等其他环境因子对鱼类繁殖也有一定的影响。对于特定鱼类,应该根据其生物学特性,适时调整鱼池的流速,满足相关需求。研究结果丰富了国内鱼类增殖放流站亲鱼池结构设计内容,推荐的亲鱼池结构型式可为鱼类增殖放流站设计提供参考。

Numerical Simulation Study of a Broodstock Rearing Pond Design for a Fish Breeding and Release Station

Fish breeding and release is one of the most effective measures for maintaining fish populations in rivers affected by water conservancy and hydropower projects. The rearing pond in a fish breeding and release station is an important artificial habitat for broodstock. The flow fields of the rearing pond directly affects the health and reproduction of the broodstock and are related to pond shape, size, water exchange rate and inlet-outlet configuration. However, few studies have investigated flow fields in these ponds. Computational Fluid Dynamics (CFD) was applied in this study to simulate the flow field of rearing ponds of different shapes and configurations. To address the maximum suitable flow velocity region for broodstock, a three dimensional kappa-epsilon turbulence model was used. The hydrodynamic conditions of circular and rectangular tanks at different flows were compared and used to develop recommendations. A circular tank with tangential inlet was recommended for broodstock culture and the most suitable diameter to depth ratio ranged from 6:1 to 3:1. Rectangular tanks are more appropriate for small sites and the recommended length to width ratio ranged from 4:1 to 2:1. This study focused primarily on fish species that prefer running water (> 0.5 m/s) in mountainous regions. For a particular fish species, the flow velocity would be adjusted to simulate preferred habit conditions. In addition to the flow field, other environmental factors, such as temperature, dissolved oxygen and pollution affect fish. In future research, the influence of these factors on the design of rearing ponds will be explored. This research provides a reference for improving the design of fish rearing ponds for fish breeding and release stations.