The impedance hole rounding on surge chamber is numerically simulated by using the k-e turbulence mathematical model for the complementation of physical model tests. The inflow and outflow resistance coefficients at the junction rounding with different radii of the impedance hole with the bottom plate of surge chamber and the bottom flow conduits are obtained. The calculated flow pattern of surge chamber without impedance hole rounding is compared with the observed one. The results show that when the flows without impedance hole rounding go through the hole, a sudden flow contraction occurs, the flow velocity is uneven, faster in the middle but slower at the sides, and the resistance coefficient is relatively large. After the impedance hole rounding, the sudden contraction effect is significantly reduced, the flows are smooth and even, and the resistance coefficient obviously decreases. The impedance hole rounding optimizes and reduces the contraction losses and may effectively reduce the resistance coefficient so as to raise the discharge coefficient of the impedance hole.%为实现物理模型与数值计算的互补,采用κ-ε紊流数学模型对阻抗孔修圆进行三维数值计算,得到阻抗孔与调压室底板连接处和与底部流道连接处不同修圆半径时流入、流出大井的阻抗系数,并将阻抗孔未修圆时的计算值与实测值进行对比分析.计算结果表明:阻抗孔未修圆时水流进入阻抗孔后发生突缩,流速分布不均,中间大、周边小,阻抗系数相对较大；阻抗孔修圆后突缩效应明显减弱,水流较为平顺、均匀,阻抗系数明显减小.阻抗孔修圆优化减小了突缩损失,能够有效减小阻抗系数,即可增大阻抗孔的流量系数.
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