整流罩在泵站肘形进水流道中的应用效果分析

肘形进水流道广泛应用于大型低扬程泵站,其弯曲段的内侧与外侧曲率半径相差较大,故流道出口存在较严重的流动不均匀性,从而影响泵站工作效率。针对此问题,本文设计了一种装在肘形进水流道末端的整流罩,并采用计算流体力学方法对传统肘形进水流道和加装整流罩的进水流道进行了对比分析。研究发现,传统肘形进水流道在弯曲段内,内侧流速比外侧流速高28.4%。在进水流道末端加装整流罩之后,进水流道出口速度分布均匀度基本保持不变,但设计工况下出口水流平均偏流角由原来的13.1°减小至4.3°,降低70%以上,水泵扬程增加2.3%,水泵效率增大2.5%。上述结果表明,整流罩在减小了进水流道出口水流平均偏流角之后,使水泵进口流态得到改善,从而降低了泵内流动损失,提高了水泵扬程和效率。该项研究工作对改善大型泵站水力设计,提高泵站运行效率具有参考价值。

Analysis on effect from application of fairing to elbow inlet passage of pumping station

The elbow inlet passage is widely used in large-scale low-lift pumping station. However，the difference between the curvature radiuses of both the inner-side and the outer-side of the bending section is larger，and then more serious non-uniformity of flow is there at the outlet of the passage，thus the operation efficiency of pumping station is to be impacted. Aiming at this problem，a fairing device that is installed on the end of the elbow inlet passage is designed herein，while a comparative analysis between the conventional elbow inlet passage and the inlet passage installed with fairing device is made with the computational fluid dynamics approach. It is found out through the study that the inner-side flowrate is 28. 4% higher than that of the outer-side inside of the conventional elbow inlet passage. After installing fairing device on the end of the inlet passage，the uniformity of the flowrate distribution at the outlet of the inlet passage is basically unchanged，but the mean deviation angle of the flow at the outlet under the design operation condition is decreased by over 70% from the original of 13. 1° to 4. 3°，while the pumping head is increased by 2. 3% and the pumping efficiency is increased by 2. 5%. The above result shows that the fairing device can improve the flow pattern at pump inlet after decreasing the mean deviation angle of the flow at the outlet of the inlet passage，thus decreases the hydraulic loss inside of pump and increases pumping head and efficiency. The study has referential value for improving the hydraulic design of large-scale pumping station and enhancing its operation efficiency.