带连接管的阻抗调压室流量系数及水力损失特性研究

Discharge Coefficients and Local Head Losses of Impedance Surge Tanks with Standpipe

受调压室与底部主管道衔接方式的影响,水流进出带连接管的阻抗调压室时的流量系数与常规阻抗调压室差别明显。通过对比分析水流进出两种调压室时的局部水头损失系数,确定了带连接管的阻抗调压室的流量系数计算公式,并对水流进出调压室的流态进行了三维数值模拟,对比分析了数值模拟结果和公式计算结果。结果表明,水流进出带连接管的阻抗调压室时水力损失分别由断面突扩、突缩、局部侧收缩和扩大四种类型组成,且连接管内水流无侧向收缩,这使得水流进出此类调压室时流量系数较常规阻抗调压室更大,采用合理的三维流场模拟技术可以有效地确定带连接管的阻抗调压室的水力损失特性。

The discharge coefficients of impedance surge tank with standpipe are significantly different from those without standpipe due to the various types of the junction between the surge tank and the tunnel.The formulae for discharge coefficients were presented by analyzing the characteristics of local head losses.The flow patterns of flow in and out the surge tank were computed by CFD technology.The results indicate that the head losses consist of the expansion and contraction of the sections,which lead to the increase of the discharge coefficients.The comparison of the results from CFD simulation and the formulae shows that the advisable CFD method can be used to estimate the head losses of impedance tank with standpipe.