Hydraulic characteristics of eccentric tapered outlet pressure box culvert of pumping station
In order to improve the undesirable flow patterns such as deviation,backflow,and flow se-paration in the eccentric tapering outlet pressure box culvert,its hydraulic characteristics were studied by combining physical model test and numerical simulation.The flow pattern,transverse velocity distri-bution ratio,and pressure distribution of the characteristic sections of the eccentric tapering outlet pres-sure box culvert were compared.The research shows that the preliminary design scheme has bad flow patterns such as bias flow,reflux,and flow separation in the eccentric tapering outlet pressure box cul-vert.The maximum transverse velocity distribution ratio of its characteristic section reaches-62.50%,and the maximum pressure difference on both sides of the long diversion pier reaches 1 679.51 Pa.By adopting the combined scheme of optimizing"diversion pier position+water-facing angle+deflecting flow baseplate structure",the unfavorable flow pattern in the box culvert is eliminated,the transverse velocity distribution ratio of the characteristic section is reduced to a minimum of-5.19%,and the minimum pressure difference on both sides of the long diversion pier is only 21.21 Pa.Under the typi-cal operating conditions of 2#,3#,and 4# units,applying this combination scheme can also optimize the flow pattern.The research results can provide a reference for the design of similar outlet pressure box culverts.