泵站出水池整流措施数值分析

为了改善泵站出水池内的不良水流流态,基于CFD软件,采用RNG模型和VOF方法对原设计方案及4种修改方案的出水池水流进行全流场数值模拟,得到泵站出水池内部的水流流态、流速、水位、水头损失及水头损失系数.计算结果表明,原方案出水池内流态紊乱,隧洞进水条件差,水流偏斜较为明显;纵向水面差为0.33~0.48 m,水头损失和水头损失系数相对较大.通过多个方案比较,推荐采用圆弧边墙+下移隧洞进口方案,对原方案的4处折角边墙分别调整为半径为45和36 m的圆弧,同时隧洞进口向下游移动10 m.该方案能明显改善出水池的流态,水流能较均匀地进入隧洞,纵向水面差减小明显,最大减幅为0.12 m;隧洞进口流速分布均匀度提高了10.3%,水头损失减小了14.7%.根据推荐方案进行物理模型试验,试验结果与数值模拟接近.

Numerical simulation of rectification measures in outlet sump of pumping station

In order to improve the flow pattern in the outlet pool of pumping station,the RNG model and VOF method was used to simulate the whole flow field in outlet sump of original design scheme and four modified schemes based on CFD software.The flow pattern,velocity,water level,head loss and head loss coefficient of the outlet sump of the pumping station were obtained.The calculation results show that the flow pattern in the outlet sump of the original scheme is disordered and the inflow condition of the tunnel is unstable and the main stream is obviously off the central line.The longitudinal water surface difference is 0.33-0.48 m,and the head loss and head loss coefficient are relatively large.Through the comparison of several schemes,it is recommended to adopt the scheme of circular arc side wall and downward moving tunnel entrance.The four corner side walls of the original scheme are adjusted to circular arcs with radius of 45 m and 36 m,respectively,and the tunnel entrance moves 10 m downstream.The scheme can obviously improve the flow pattern of outlet sump,and the flow can enter the tunnel more evenly.The longitudinal water surface difference decreases the most and is 0.12 m.The uniformity of velocity distribution at the entrance of the tunnel is increased by 10.3%,and the head loss is reduced by 14.7%.According to the recommended scheme,the physical model test results are close to the numerical simulation.