本文采用模型试验和理论分析相结合的方法,对阻塞式旋流泄洪洞的泄流规律和影响因素进行了分析。结果表明:泄流规律与旋流洞流态密切相关,进口和竖井非淹没时为堰流泄流,淹没时为有压孔流泄流;进口淹没时泄流量受起旋器喉口和阻塞孔口共同影响,且两个断面处均为有压孔流泄流规律:起旋器喉口流量系数与喉口前水头损失和喉口断面压强有关,且后者为主要影响因素;阻塞孔口流量系数与阻塞前水头损失、以及阻塞导致的相对空腔半径、旋流角和相对壁面压强的旋流特性变化有关;起旋器喉口流量系数在阻塞面积收缩比m=0.56时约为0.4,m≤0.18时介于0.55—0.65;阻塞孔口流量系数在m=0.56时接近0.5,m≤0.18时介于0.25—0.32:给出了起旋器喉口断面面积设计计算表达式。
Discharge through a rotary flow spillway tunnel with blockage and its influencing factors were studied with model test and theoretical analysis. This discharge is closely related to the flow pattern in the tunnel: it is a weir flow when the tunnel inlet and shaft are not submerged, while an orifice flow when submerged. In the condition of submerged tunnel inlet, the discharge is influenced by both the vortex generator inlet and blockage orifice, and the flows at these two locations follow the law of pressurized orifice flow. At the generator inlet, the discharge coefficient depends on the energy loss upstream and the local pressure, and the latter is the main factor. At the blockage orifice, it depends not just On the energy loss upstream, but on the variations of flow swirling behaviors caused by the blocking device, such as relative cavity radius, rotary angle, and relative wall pressure. At the generator inlet, this coefficient is 0.4 at contraction ratio m=0.56 and in the range of 0.55-0.65 at m〈0.18, while at blocking orifice, it is close to 0.5 at m=0.56 and in the range of 0.25-0.32 at m≤0.18. An expression for calculation of the cross-sectional area of generator inlet has been derived.