连接管对调压室涌波水位和水锤压力的影响

在传统大波动过渡过程计算中,调压室底部连接管的影响往往是作为阻抗孔来考虑,在连接管较长的情况下,采用阻抗孔处理时而忽略了连接管的水体弹性,因而容易造成较大误差。通过建立考虑了连接管及不考虑连接管时的调压室节点数学模型,采用Gardel公式来处理调压室的阻抗系数,将调压室的阻抗系数变为负荷实际情况的动态阻抗系数,并结合具体工程实例来分析连接管的长度及管径的变化对调压室涌浪、蜗壳进口压力以及机组转速所产生的影响。研究结果表明,对于连接管较长的情况,应考虑到连接管的作用,为了能充分反射水锤,连接管的面积不宜过小。

Influence of connecting pipe on surge water level and water hammer pressure in surge tank

In the traditional calculation of large fluctuation transition process, the influence of connecting pipe on the bottom of surge tank is often considered as an impedance hole. When the connecting pipe is long, the water elasticity in the connecting pipe is neglected, which is likely to cause a large error. Node math model of the surge tank is established in two ways with consideration and without consideration of connecting pipe. The Gardel's formula is used to treat the impulse coefficient as a dynamic impulse coefficient which is in accordance with the actual condition. In combination with concrete examples, the influence of length and diameter of connecting pipe on the surge tank surge fluctuation, inlet pressure and unit speed is studied. The results show that in the case of long connecting pipe, it is necessary to consider its influence, and in order to reflect the water hammer waves effectively, the pipe connecting area should not be too small.