【摘要】 对顺直、台阶及收缩式洞塞的脉动压力进行了测量和分析,并结合某工程导流洞改建洞塞泄洪洞项目,从脉动压力的角度分析了洞塞段的抗空化性能。结果表明:3种洞塞的脉动压力强度在距离洞塞进口0.1～0.3倍洞径处达到最大值,随后迅速衰减,在距离洞塞进口4倍洞径后趋于平稳;在相同的流速及相同的出口直径下,顺直洞塞的脉动压力均方根值最大,台阶洞塞次之,收缩洞塞最小;在脉动压力均方根最大处,3种洞塞的压力接近正态分布。对于收缩洞塞,采用6倍均方根计算最小压力是偏于安全的;在1:40的正态模型上实测了某洞塞泄洪洞的压力分布,结果表明,泄洪洞段的最小瞬时压力为3.4×9.8kPa,发生空化的可能性很小。更多还原

【Abstract】 The fluctuating pressure for three plug dissipaters,named as linear plug,stepped plug and gradually contracted plug,were measured and analyzed.From the perspective of fluctuating pressure,the characteristics of anticavitation for gradually contracted plugs which were arranged in discharge tunnel were investigated.The results showed that the maximum RMS(root-mean-square) of wall fluctuation pressure appears at 0.1 ～ 0.3 times tunnel diameter away from inlet of the plug,decreases rapidly along the plug wall and then becomes stability after 4 times tunnel diameter.The RMS of wall fluctuation pressure of the contracted plug is smaller than that of other two plugs when the outlet diameter and the flow velocity are certain.The fluctuating pressure distribution is approximately the Gauss distribution.For gradually contracted plug,it is conservative to calculate the minimum pressure using 6 times the RMS of fluctuation pressure.Pressure distribution were measured and analyzed for a plug discharge tunnel on 1:40 orthodox model.The results showed that the minimum pressure in the tunnel is 3.4 ×9.8 kPa,so the probability of cavitation occurrence is small.更多还原