肘形进水流道水力优化仿真计算与试验

为了分析大型泵站肘形进水流道的开挖量与流道水力损失及内部流态之间的变化规律,对流道设计进行了研究.设计了8组肘形进水流道方案,其中1-4组方案流道底板上翘角度不同(方案1底板上翘角为0),5-8组方案流道后壁弯曲段半径R不同.基于雷诺平均N-S方程和标准k-ε湍流模型,运用SIMPLEC算法,模拟了额定流量下肘形进水流道的8组方案三维流场.结果表明:1-4组,底板倾角不断抬高.当底板上翘7°时,流道水力损失只有略微增加,流道进口底板较方案1抬高1.15 m;继续增加底板倾角,水力损失明显增加.5-8组,流道后壁弯曲段半径R不断减小.当R为1.03倍叶轮直径时,水力损失较方案1增加14.5 mm(水力损失以水头高度表示),整体流道底板抬高0.36 m;若继续减小R值,水力损失明显增加.对优选的底板上翘7°流道方案进行模型试验.换算到原型后,流道水力损失与计算结果基本吻合.

Numerical simulation and experimental of optimum hydraulic design for elbow inlet passage

In order to analyze the relationship between pumping station engineering excavated volume of elbow inlet passage and hydraulic loss of passage, the inlet passage was designed. The 8 schemes of elbow inlet passage were designed. In examples 1-4, the floor tilt angle of the passage was different(in example 1, floor tilt angle was 0°). In examples 5-8, the radius of backward wall of the passage bending section was different. Based on the Reynolds averaged N-S equation, standard turbulent model and SIMPLEC algorithm, the 3-D flow field in 8 examples of elbow inlet passages was simulated in rated flow. The simulation results show that in examples 1-4, the floor tilt angle was raised. When the floor tilt angle was 7°, hydraulic loss of the passage increased slightly and the imported floor height of the passage was 1.15 m higher than that in example 1; the floor tilt angle continues to increase and hydraulic loss increased obviously. In examples 5-8, the radius of backward wall of the passage bending section decreased continuously. When the R was 1.03 times longer than impeller diameter, hydraulic loss was 14.5 mm higher than that in example 1(hydraulic loss was measured by height of the water column)and the floor height of the passage was 0.36 m higher than that in example 1. If the R continues to decrease, hydraulic loss increased obviously. The model test for the preferred example of floor tilt angle 7° was conducted. The results were basically in agreement with calculated results.