有压泄洪洞弯道压力特性数值模拟与试验研究

Numerical Simulation and Experimental Research on Pressure Characteristic of Curved Section of Pressure Spillway Tunnel

有压泄洪洞转弯段容易出现负压问题,严重的可能影响泄洪洞的运行安全。根据κ-ε模型,运用数值模拟方法对石门水库有压泄洪洞,在闸门全开、局开及不同库水位条件下的洞身转弯段压力特性进行了研究。研究发现:有压泄洪洞水流在转弯段存在明显偏流特性,形成凹岸压力大、凸岸压力小、顶部有较大负压区现象;闸门全开时,库水位较低,弯道前半段洞顶容易出现负压,随着库水位的升高,压力逐渐增加;库水位保持不变时,随着闸门开度的减小,洞顶低压区压力也不断增加。数值模拟结果与模型试验结果吻合良好。该研究结果表明,通过闸门开度的调整,既可避免不安全运行方式的出现,也可提高泄洪洞的运行灵活性。

The curved section of pressure spillway tunnel is easily prone to negative pressure which could affect the safe operation of tunnel. Based on κ-ε model, the numerical method is used to research the pressure characteristic of curved section of spillway tunnel in Shimen Reservoir on the conditions of gate full opening and partial opening in different reservoir levels. It is found that： （a） the bias flow is obviously exists in curved section and the pressure is larger in concave side, smaller in convex side and negative in top area; （b） when the gate is fully opened, the top area of curved section is easily prone to negative pressure as the reservoir level is lower, and the pressure will increase with the increasing of water level; （c） when the reservoir level is stable, the pressure of top area also increases with the decreasing of gate opening. The numerical results are in good agreement with model test resuks. The study shows that, by adjusting the opening of gate, unsafe operation can be avoided and the operation flexibility of spillway tunnel can also be improved.