基于CFD的导流墩几何参数对闸站合建枢纽通航水流条件的影响研究

闸站合建枢纽通航时容易在导流墩附近出现复杂水流现象。【目的】改善导流墩墩头前的斜流、偏流以及面层横向速度和轴向速度大的问题。【方法】基于计算流体力学(CFD)对某闸站合建枢纽节制闸通航水流条件进行数值模拟,研究分析了导流墩长度、开孔与否、开孔宽度、相邻孔口中心间距及开孔高度等参数对闸站合建枢纽通航水流条件的影响。【结果】综合考虑导流墩前横向流速、轴向流速及斜流面积,采用单因素递进分析表明,随着导流墩长度增加,导流墩前流速和斜流面积先减小后增大;当开孔宽度增加到4.5 m时,墩头前流速进一步减小,大于4.5 m时,墩头前流态恶化;随着开孔中心间距的增加,导流墩前流速呈现先减小后增大的趋势,孔口中心间距为6.25 m时,流态较优;当开孔高度增加到3.8 m时,墩头前流速和斜流面积进一步减小,大于3.8 m时,墩头前流速和斜流面积随之增大。【结论】通航水流条件的优劣受导流墩结构影响显著,导流墩开孔能够减小墩头前水流面层横向和轴向速度及斜流面积,提高通航安全性。导流墩最优开孔方案为:导流墩长度25 m、开孔宽度4.5 m、相邻孔口中心间距6.25 m、开孔高度3.8 m,相应墩头前水流横向和轴向速度及斜流面积分别为0.25 m/s、0.75 m/s、12.56 m~2。

Using CFD Model to Analyze the Influence of Geometric Parameters of Diversion Piers on Water Flow in Sluice Station

【Objective】Water flow in the proximity of diversion pier in sluice station is complicated. The objective of this paper is to present a method to improve our understanding of slanting flow, bias flow, large transverse and axial flow in front of diversion piers in sluice stations.【Method】The method was based on the computational fluid dynamics software(CFD), in which the influence of the length of the diversion pier, its openness, duration of openness, distance between adjacent hole and height of the opening, on flow in the sluice station was analyzed.【Result】Considering the combined impact of transverse flow velocity, axial flow velocity and oblique flow area in front of the diversion pier, single-factor progressive analysis showed that with the increase in the length of the diversion pier, the flow velocity and the inclined flow area in front of the diversion pier first decreased followed by a fall. When the opening width increased to 4.5 m, the flow velocity in front of the pier was reduced further and the state of the pier deteriorated when the pier head was larger than 4.5 m. With the increase in the center spacing, the flow velocity in front of the diversion pier first decreased followed by a decline. When the center spacing was 6.25 m, the flow state was the best. When the opening height increased to 3.8 m, the flow velocity and the oblique flow area in front of the pier were further reduced; the flow velocity and the oblique flow area in front of the pier were further increased when the opening height was larger than 3.8 m.【Conclusion】The navigable flow condition depends greatly on the structure of the diversion pier. The opening of the diversion pier can reduce the lateral and axial flow velocity and the oblique flow area of the surface layer of the flow surface in front of the pier head, thereby improving navigation safety. The optimal opening of the diversion pier is that the length of the diversion pier is 25 m, the opening width is 4.5 m, the adjacent hole center distance is 6.25 m, and the opening height 3.8 m. The transverse and axial flow velocity and the oblique flow area of the corresponding pier head are 0.25 m/s, 0.75 m/s and 12.56 m~2 respectively.