通气对水平旋流内消能泄洪洞水力特性的影响

Influence of Ventilation on Hydraulic Characteristics of Level Rotary Flow in Internal Energy Dissipation Tunnel

通过模型试验,研究了水平旋流条件下通气对水力特性的影响,结果表明,通气对流态、泄流量、壁面压强和空腔内的气体压强均有较显著的影响。通气时,环流空腔的直径增大,流动稳定;随通气孔直径的增大,泄流量和通风量均先增大然后减小,具有最大值,且环流空腔内的负压值迅速减小并趋于零;不通气或通气孔的直径较小时,负压值较大,壁面压强也较大,这与通常的认识不同;随下游水位的升高,在下游洞口临近淹没时,通气量达到最大。

Influence of ventilation on hydraulic characteristics of level rotary flow has been investigated on the hydraulic model of an internal energy dissipation tunnel. Ventilation has obvious influence on the flow pattern, discharge, wall pressure and air pressure inside level rotary flow. When ventilating, the cavitaty diameter of level rotary flow increases and the flow becomes more stable. With the increase of diameter of ventilation hole, the quantity of both discharge and ventilation first increases then decreases, and reaches a maximum, and the negative air pressure inside level rotary flow quickly reduces and tends to become zero. When not ventilating or the diameter of ventilation hole is smaller, the negative air pressure is becoming larger and the wall pressure also has the behavior, which is diverse from our conventional understanding. With the rise of down-stream water level till the outlet of level tunnel to be just submerged, the quantity of ventilation gets max.