贯流式水轮机内部压强变化对鱼体损伤分析研究

Analysis and research on fish damage caused by internal pressure change of tubular turbine

鱼类在通过贯流式水轮机流道时会遭遇撞击、压强变化等引发的损伤。本文基于试验和CFD分析方法探究了不同工况下贯流式水轮机全流道压强变化对鱼的损伤机理及阈值。通过试验实现鱼经过水轮机过程中压强变化情况的高精度仿真,研究鱼类在贯流式水轮机内部受压强及压强梯度的影响。试验结果表明:正压状态下加压至最大压强0.68 MPa时,对鱼损伤不明显;随着压强阈值的降低,受损伤和死亡的试验鱼越多,负压状态下降压至压强-0.015 MPa时,鱼类受到损伤,下降至-0.075 MPa时,鱼类全部死亡。通过数值计算分析得出:相对压强小于-15 kPa的区域主要位于叶片背面靠近进口边的位置,且当贯流式水轮机在不同导叶开度下运行时,相对压强小于-15 kPa的区域随着流量的增加呈增多趋势,鱼类遭受压强损伤概率随着流量的升高呈增大趋势。当水轮机在最小水头的大流量工况时,鱼类遭受压强损伤概率达到了最大值6.45%。鱼类遭受压强梯度损伤概率随着流量的升高呈先增大后减小趋势。当水轮机在最大水头的导叶开度为60 mm时,鱼类遭受压强梯度损伤概率达到了最大值4.61%。

Fishes will suffer damage caused by impact and pressure change when passing through the pas⁃sage of tubular turbine.In this paper,based on the experimental and CFD analysis methods,the damage mechanism and threshold of fish caused by the change of pressure in the whole channel of tubular turbine under different working conditions are explored.The high-precision simulation of the pressure change of fish passing through the turbine is realized through experiments,and the influence of pressure and pressure gradient on fish in the tubular turbine is studied.The results showed that when the pressure was increased to 0.68 MPa under positive pressure,there was no obvious damage to the fish;with the decrease of the pressure threshold,more and more fish were injured and died.When the pressure decreased to-0.015 MPa,the fish were injured,and when it dropped to-0.075 MPa,all the fish died.Through numerical cal⁃culation and analysis,it is concluded that the area with relative pressure less than-15 kPa is mainly locat⁃ed at the back of blade near the inlet side,and when the tubular turbine operates under different guide vane openings,the area with relative pressure less than-15 kPa increases with the increase of flow rate,and the probability of fish suffering from pressure damage increases with the increase of flow rate.When the turbine is in the condition of large discharge with the minimum head,the probability of fish suffering from pressure damage reaches the maximum value of 6.45%.With the increase of flow rate,the damage probability of fish increases first and then decreases.When the guide vane opening of the turbine is 60mm at the maximum head,the probability of fish suffering from pressure gradient damage reaches the maximum value of 4.61%.