为研究泥沙粒径对分离鳃的速度场及水沙分离效果的影响,采用层流模型和欧拉模型,运用PC-SIMPLE算法,对分离鳃内的水沙两相流流场进行了三维数值模拟。计算结果表明:当泥沙粒径d=0.0001mm时,分离鳃内的流场与其他泥沙粒径时有所不同;当0.005mm≤d≤0.035mm时,分离鳃内不同粒径泥沙水流的流场相同;当0.015 mm≤d≤0.035 mm时,分离鳃处理泥沙效果最好,且泥沙粒径越大,去除率越高,水沙分离速度就越快。

Three-dimensional numerical simulation adopting the laminar model and Euler model were conducted to the flow field of water-sediment two-phase in gill-sheet separation device to study how the sediment grain size effects upon velocity field and water-sediment separation by using PC-SIMPLE algorithm. The results show that the velocity flow is the same in the gill-sheet separation device when sediment grain size ranges from 0.005 mm to 0.035 mm and when the it is different the sediment grain size is 0.000 1 mm. The best performance is observed when gill-sheet separation device handles sediment grain size that ranges from 0.015 mm to 0.035 mm. Additionally, the greater sediment grain size is, the higher removal is. Meanwhile the faster the water-sediment separation is.

根据滴灌实际运行情况，采用分段粒径浑水持续灌溉的试验方法，分析了泥沙颗粒粒径及进口压力对迷宫式流道滴头的流量、均匀度及堵塞的影响。结果表明：在粒径小于0．125 mm 的泥沙颗粒中，较小颗粒的制紊效应要大于较大颗粒的制紊效应，泥沙颗粒粒径及进口压力均是影响灌溉均匀度的因素；含沙量较低时（0．5 g/L），粒径是影响滴头堵塞的主要因素，在0．0308～0．125 mm 粒径范围内，粒径较小时更容易引起堵塞，进口压力不同时容易引起堵塞的敏感粒径范围不同，压力为0．15及0．105 MPa 时，敏感粒径为0．045～0．075 mm ，进口压力降至0．075 MPa后，敏感粒径为0．0308～0．045 mm ；连续灌溉条件下压力不是影响滴头堵塞的主要因素。

According to the actual situation of drip irrigation ,the influences of sediment size distribution and inlet pressure on irriga-tion uniformity ,flow and clogging of labyrinth-path emitters were investigated through the method of muddy water continued irriga-tion .The result showed that turbulence effects caused by smaller particles was more distinguished than bigger ones ;both sediment size distribution and inlet pressure were the factors that affected irrigation uniformity when the particle sized in muddy water were less than 0 .125 mm ;sediment particle size was the main factor of emitter clogging with low sediment concentrations ;emitter clog-ging would be caused more easily by smaller particles ;different inlet pressures correspond to different sensitive size that caused emit -ter clogging easily ;size sensitive is from 0 .045 to 0 .075 mm at the pressure 0 .150 and 0 .105 MPa ,while from 0 .030 8 to 0 .045 mm at the pressure 0 .075 ;inlet pressure was not the main facto

为探明泥沙粒径与含沙量对内镶片式斜齿形迷宫流道滴头的堵塞过程和原因,采用筛分法,分选出6个小于0.1 mm的粒径段,配制成不同含沙量的浑水,在恒压条件下,采用周期性间歇灌水试验观测流量变化,通过电镜扫描法观测堵塞泥沙结构。试验结果表明:粒径为0.075≤D0.1 mm和0.03≤D0.038 mm的泥沙易引起滴头堵塞;粒径为0.038≤D0.05和D0.02 mm的泥沙较难引起堵塞,且含沙量变化对堵塞的影响较小;粒径0.02≤D0.03 mm和0.05≤D0.075 mm的堵塞情况介于上述两者之间。当含沙量为1.2~1.3 g/L时,是最易引起堵塞的临界含沙量。当0.038≤D0.1 mm时,泥沙在流道内不易形成团聚体,造成滴头堵塞的原因是泥沙沉降、堆积;当D0.038 mm时,泥沙易在流道中凝结成大的团聚体,是造成滴头堵塞的主要原因。

Drip irrigation technology is widely used due to its advantages including high efficiency water saving, ability to adapt to the terrain and so on, but the problem of emitter clogging has been always a baffled to researchers. Emitter clogging basically has three classes, respectively is physical clogging, chemical clogging and biological clogging, of which the most common is physical clogging and it is represented by sediment clogging. Studies show that even if the irrigation water after precipitation filtration, there is still have particle size of sediment particles which are less than 0.1mm get into the emitters causing emitter clogging. However, previous studies on this problem multi-use of computer simulation method to research the influence of emitter anti-clogging by emitter structures, test verification is relatively rare and most studies only from a macro perspective to observe emitters clogging, no in-depth study on the clogging mechanism. In addition, the previous researches

为了掌握泥沙介质在水轮机转轮中的分布规律以及对转轮压力场的影响,该文应用固液两流体多相流动模型,充分考虑了固液两相间的相互作用,通过求解雷诺时均N-S方程和重正化群k-ε湍流方程,对不同泥沙介质条件下水轮机转轮通道中的流动进行数值研究。研究结果表明,含沙水会导致水轮机转轮叶片表面压力载荷增大,固液两相间速度差异是导致叶片表面泥沙体积浓度分布的变化的主要原因。小粒径泥沙在叶片表面分布均匀且体积浓度低,大粒径泥沙会集中分布在叶片的前缘及出水边等区域。该研究可为多泥沙电站水轮机转轮抗泥沙设计提供参考。

Sediment erosion of hydraulic turbine is the complicated engineering problem related to such factors as operating conditions of hydraulic turbine, solid-liquid two-phase flow characteristics and sediment properties. In this paper, the three dimensional full channel geometric model of prototype turbine is established to understand change in internal pressure of runner and sediment distribution in runner channel under different sediment flow conditions. The hydraulic turbine mainly consists of spiral case, vane, runner and draft tube. Every part generates its corresponding independent meshes, and then is connected with each other by internal interfaces. The total number of grid cell is 7 888 784 in computational domain. Considering solid-liquid interactions fully, based on Eulerian-Eulerian multiphase flow model, Reynolds-averaged Navier-Stokes and RNG k-ε turbulence equations are numerically solved to study internal flows of hydraulic turbine runner under different sediment f

针对黄河内蒙古段河水高含沙问题，通过改变多级斜板水沙分离装置中的斜板间距，探讨了不同流量、不同浓度浑水下斜板间距对泥沙分离率的影响。结果表明：第一级和第二级分沙装置中斜板间距越小，水沙分离效果越好；第三级分离装置的斜板间距减小到2 mm时，其对提高水沙分离率的影响不明显，而且会导致泥沙淤积，不利于排沙。同时分析了不同流量下斜板间距对排沙孔分离出的泥沙中值粒径的影响，结果表明：在同一流量下，排沙孔泥沙颗粒粒径随斜板间距的增大而增大。

For the hyper-concentration flow of the Yellow River in Inner Mongolia,the paper discussed the effect of inclined plate spacing’ s on sediment separation rate in different discharge and concentration by changing the inclined plate spacing’s of multilevel water-sediment separation device. The results show that the smaller the inclined plate spacing is,the better the effect of the water-sediment separation is, in the first and second level water-sediment separator;when the inclined plate spacing of the third separator reduced to 2mm,the effect is not obvious and it is easy to cause sediment deposition disadvantage of desilting. Besides,the paper analyzed the effect of inclined plate spacing’s on sediment median sizes of sediment flushing outlet in different discharge. The results show that the sediment sizes of sediment flushing outlet is increased with the increase of the inclined plate spacing under the same discharge condition.