Experimental study on damping coefficient of tailrace surge tank shared by two units

The influences of the variation of discharge ratio, impedance hole area and unit number on the damping coefficient of the tailrace surge tank when water flows in and out were researched, and the physical model study of the tailrace surge tank shared by two units was conducted. The results show that the damping coefficient increases with the increment of discharge ratio and the decrease of impedance hole. In the case of flow separation case, the damping coefficient of tailrace surge tank under two units operation is larger than that of single unit; in the case of flow confluence, there is no much difference between the single unit operation and two units operation. The results can provide reference for the design and research of similar tailrace surge tank.