排沙漏斗悬板径向坡度对流场影响的试验研究

为了弄清楚溢流悬板径向坡度改变对排沙漏斗流场的影响, 通过物理模型试验方法, 利用粒子图像流场测速技术(PIV) 对悬板径向坡度分别为 0、0.087、0.173、0.259 时的排沙漏斗模型三维速度场进行了量测, 并结合排沙漏斗工作原理对各工况下的切向速度、径向速度、垂向速度及流线进行了对比分析。结果表明: 随着悬板径向坡度增加, 漏斗室内旋流强度增大, 空气涡面积增大, 排沙耗水率降低, 泥沙颗粒向室内运动机率增大, 淤积在悬板上的可能性减小; 悬板坡度对漏斗室内的二次流强度和形成位置影响较大, 其中坡度为 0.173 时二次流最为稳定, 坡度为 0.259 时, 无二次流形成, 不利于底部泥沙输移至排沙底孔; 垂向速度分布结果表明坡度为 0.259 时过渡区垂直向上流速较少, 泥沙落淤悬板或者随流溢出的机会最小, 但垂直速度相比切向速度和径向速度而言较小, 且过渡区范围很小, 对悬板落淤和截沙率的影响可以忽略不计。 In order to find out the influence of the change of the radial slope of overflow suspended slab on the flow field of the vortex settling chamber, through physical model tests, we used the particle image flow velocity measurement technique (PIV) to measure the three-dimensional velocities of the vortex settling chamber with the radial slope of suspended slab at 0, 0.087, 0.73, and 0.259. With consideration to the working theory of vortex settling chamber, we compared and analyzed the tangential velocity, radial velocity , vertical velocity, and streamline of each working condition. The results showed that with the increase of the radial slope of the suspended slab, the swirling intensity in the vortex settling chamber increased, the air vortex area increased, the water consumption rate decreased, the probability of sediment particles moving to the interior increased, and the possibility of deposition on the suspended slab decreased. The slope of the suspended slab had a great influence on the strength and formation position of secondary flow in the vortex settling chamber. The secondary flow was the most stable at a slope of 0.173. No secondary flow was formed when the slope was 0.259, which was not conducive to the transport of bottom sediment to the bottom hole of sediment discharge. The results of vertical velocity distribution showed that when the slope was 0.259, the vertical upward velocity of transition zone was small, and there was a minimum chance of sediment silting or overflowing . However, the vertical velocity was smaller than tangential velocity and radial velocity, and the transition zone was very small. The influence of vertical velocity on the deposition and sediment interception rate of suspended slabs was negligible. 国家自然科学基金项目( 59379394) ; 新疆农业大学研究生科研创新项目( XJAUGRI2016032)