摘要
鱼类在通过混流式水轮机流道时会遭遇最低压强及压强梯度引发的压强损伤以及剪切应力引发的剪切损伤。为了辨识混流式转轮中压强损伤和剪切损伤的主次关系,进而有针对性的开展混流式转轮的鱼类生态友好性能优化,该文基于计算流体动力学分析方法研究了不同水头条件下混流式转轮内超出压强以及剪切损伤阈值的体积分布规律,并获得了不同工况下混流式转轮内压强、压强梯度以及剪切应力引发鱼类受损的概率。结果表明:鱼类受压强及剪切损伤的概率与流量成正相关关系,对于该文分析的混流式转轮,鱼类受最低压强损伤的概率在最小水头的最大流量工况下达到最大值9.1%,剪切损伤及高压强梯度损伤的概率在额定工况下达到最大,分别为0.823%和8.31%。在相同工况下进行3种损伤概率的对比后发现,在大流量工况下,鱼类受最低压强和高压强梯度损伤的概率更大,在小流量工况下则是压强梯度损伤概率相对较高,所以综合分析结果可知最低压强和高压强梯度是开展亲鱼型混流式转轮优化时需要考虑的主要因素,而剪切应变率则是次要因素。
Hydropower is a major source of renewable,noncarbon-based electrical energy.Although hydropower has many environmental advantages,hydropower dams alter the natural ecohydrological conditions of the rivers and cause significant ecological impact,especially for fish that live in or migrate through impounded river systems.Injury and mortality of fish that pass through hydraulic turbines and other downstream passage routes can result from several mechanisms,such as rapid and extreme pressure changes,shear stress,strike,cavitation,and grinding.For example,a large or fast pressure drop can lead to internal bleeding of fish,rupture of the swim bladder or vapor bubbles in eyes,which will result in direct mortality and reduces the ability to escape predators in the tailrace.Shear stress can causes fish scales flake,muscle tissue tearing,bruising,and even the fish body are cut off.So understanding the biological responses of fish to the conditions of hydraulic turbine is important for designing advanced fish-friendly turbines.Since the injury of fish may be caused by a combination of multiple damage mechanisms,it is necessary to identify primary and secondary damage mechanisms by research.In this paper,the computational fluid dynamic analyze method was adopted to simulate the three dimensional turbulent flow in an francis turbine.The simulation was conducted at different discharge conditions of maximum,rated and minimum head.The rated head of the turbine Hr is 106 m,the maximum head Hmax is 120 m and the minimum head Hmin is 73 m.The whole flow passage of the turbine was discretized by hexahedron structured mesh,and the SST k-ωturbulence model was used in the simulations.Then,the fish friendly threshold for pressure,pressure change rate and shear strain rate were used to analyze the volume size and distribution that may lead to the damage of fish.The ratio of the volume exceeding the fish friendly threshold to the total volume of the runner channel was defined as the fish damage probability.Finally,according to the calcul
作者
朱国俊
吉龙娟
冯建军
罗兴锜
Zhu Guojun;Ji Longjuan;Feng Jianjun;Luo Xingqi(Institute of Water Resources and Hydro-electric Engineering,Xi’an University of Technology,Xi’an 710048,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2019年第2期55-62,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金重点项目(51339005)
国家自然科学基金项目(51679195)
陕西省自然科学基础研究计划资助项目(2018JM5102)
关键词
鱼
流量
数值分析
水轮机
混流式转轮
鱼类损伤概率
压强损伤
剪切应力损伤
fish
discharge
numerical simulation
hydraulic turbine
francis runner
fish damage probability
pressure damage
shear stress damage
