Hydraulic Performance Analysis Of Bi-directional Pumping Stations Group With Muti-units

The forebay connecting diversion channels and intake sump, which is an important component of intake structure of pumping station. Good water conditions can improve the pump cavitation performance and energy performance. The forebay is divided into two basic types:front inflow forebay and side-direction forebay. The former’s water flow direction is the same to water in intake sump, with the water flow stably diffusing and flow pattern smooth-going. The later’s water flow direction is orthogonal or oblique with intake sump’s. Water flow disorders and unevenly distribute, which will easily lead to sedimentation and affect the normal operation of pumps. In practical engineering, limited by terrain conditions, water diversion pump station close to river and combined sluice-pumping station, and other pump station with complex operation conditions will adopt the side-inlet layout.With the rapid development of computer and fluid computing software technology increasingly matures, research on three-dimension numerical simulation of the forebay of pumping station became one of the hot spots. Based on FLUENT software platform, this article adopts the Realizable κ-ε turbulence model to simulate the water flow in intake channels, forebays and inlet passages of muti-unit two-way pumping station groups. The results showed that flow pattern in side-inlet forebay disordered, and in the first three stations, there are large-scale counter-clockwise circuiting zone throughout the entire forebay. Swirling center is located on inside of the bend where may cause sediment deposition and bad flow pattern. So the side-inlet flow is detrimental to pump running safely and efficiently. There are two almost symmetrical big vortexes in the opposite direction appearing at the fourth station wing walls. Velocity distribution at inlet is uneven and flow pattern in forebays need to improve. Compared with the experimental results, the numerical simulation results adopting the realizable k-s turbulence model to calculate the muti-forebay are believable.To improve the flow pattern in forebay, six engineering measures were adopted on the basis of the original plan, such as adding sills, inverted "Y" diversion pier, combined-sills and inverted "Y" diversion pier, changing forebay into divergent type, adding equilateral triangular prism and division pier. Then three-dimensional physical model was established for each scheme. By comparing the numerical simulation and analysis results, the most economic and reasonable scheme was ultimately put forward in this article.