透水斜槛对溢洪道泄槽弯道水流改善效果试验

Model test of flow improvement effect of the permeable oblique sill on the bend in spillway chute

为了探索透水斜槛对溢洪道泄槽弯道水流的改善效果,在弯道底板布置了5道斜角45°透水率分别为27.9%、37.9%、49.5%的透水斜槛进行了模型试验。利用试验结果,计算了弯道横断面水面均匀度及提高率、凹凸岸水面差及减少率等指标,以此分析不同透水率斜槛、不同流量条件下弯道段水流的改善效果影响。结果表明:弯道设置透水斜槛后能够改善弯道水流,提高弯道水流均匀度,降低凹凸岸水面差;透水率对水流改善效果有影响,在相同流量情况下,透水率越小,斜槛对水流改善的效果越好;斜槛改善水流的效果随流量变化,流量越小,改善效果越明显。但就弯道横断面水面均匀度改善效果而言,不同透水率、不同流量之间相差不大。

In order to explore the flow improvement effect of permeable oblique sill on the spillway chute bend,we carried out a model test of five permeable oblique sills(laid at an angle of 45°)with a permeable rate of 27.9%,37.9%and 49.5%.Based on the test results,we calculated the water surface evenness and the corresponding improvement rate,the water surface difference between concave bank and convex bank and the corresponding decrease rate,so as to analyze the effect of different permeable rates of the sill and different flow rates on improving the flow of the bend.The results were as follows.Firstly,the permeable oblique sill set at the bend could strongly improve the bend flow,increase water surface evenness at the bend,and decrease water surface difference.Secondly,permeable rate could affect the flow improvement effect.Under the same flow rate,the smaller the permeable rate,the better the effect of the sill on flow improvement.Thirdly,the effect of the sill on flow improvement would vary with the flow rate;the effect was more obvious when the flow rate was low.Regarding the improvement effect on the water surface evenness at the bend,the different permeable rates or flow rates did not make much difference.