进水流道对泵装置性能影响的数值模拟分析

为了研究进水流道内部流态对泵装置性能的影响,采用CFX三维软件对高度及喉部高度大、高度及喉部高度小的两种肘形进水流道装置的三维流场进行数值模拟,分析比较了这两种肘形进水流道与泵装置的水力特性。方案1肘形进水流道的高度大,挖深大,土建投资大,且喉部高度大,弯肘段脱流严重;方案2肘形进水流道高度小,土建投资小,同时喉部高度小,有效抑制了弯管脱流问题。结果表明:在最优工况下(Q=320 L/s),肘形进水流道方案2比方案1的流道出口断面速度均匀度高1. 6%;速度加权平均角度高7. 34°;进水流道水力损失降低0. 128 m;装置效率提高4. 22%;装置高效区流量范围拓宽40%。因此,为了保证泵装置高效、安全地运行,应充分重视在实际工程中进水流道对泵装置性能的影响以及肘形进水流道喉部高度对进水流道流态的影响。

Numerical simulation analysis on influence of inlet flow-passage on performance of pump device

In order to study the influence from the internal flow pattern of inlet flow-passage on performance of pump device，a numerical simulations on the 3 － D flow fields of two types of elbow inlet flow-passages with large height and throat height and with small height and throat height are made with CFX 3 － D software，and then the hydraulic characteristics of these two type of elbow inlet flow-passages and their pump devices are comparatively analyzed. In scheme 1，the civil construction of the investment for the elbow flow-passage with large height and excavation depth is large，while the height of its throat is large as well，thus the flow-off in its elbow bending section is quite serious. In scheme 2，the civil construction investment of the elbow flow-passage with small height is small，while the height of its throat is small，thus the problem of the flow-off in its elbow bending section is effectively restricted. The result shows that under the optimal operation condition (Q = 320 L/s)，the uniformity of the flow velocity at the outlet cross-section of the flow-passage in scheme 2 of the elbow inlet flow passage is higher than that of the scheme 1 by 1. 6% ，for which the weighted mean angle of the velocity is higher by 7. 34°，the hydraulic loss of the inlet flow-passage is lowered by 0. 128 m，the efficiency of the device is enhanced by 4. 22% and the discharge range of the efficient region of the device is widened by 40%. Therefore，it is necessary to pay full attention to the influence from inlet flow-passage on pump device in the actual engineering case as well as the influence from the throat height of elbow inlet flow-passage on the flow pattern in inlet flow-passage，so as to ensure the efficient and safe operation of pump device.