A STUDY ON ORIFICE TYPE SURGE TANK SYSTEM

Abstract

The term water hammer, which is synonymously used for the term hydraulic transients in the pipe networks, that describes the effect of unsteady flow of liquid in pipe network. It occurs due to the disturbed momentum of flowing liquid by the closing of gate of the turbine or by other accidental activities in the hydro-electric power plant. It is difficult to compute the hydraulic transient correctly; Method of Characteristics is the most appropriate method to compute transient analysis. Hydraulic transient in the water conducting system of a typical hydro-electric power plant has been computed in this study. The water conducting system of hydro power plant is consisted of HRT of length 500m, orifice type surge tank of 1 5m diameter and 2.43m diameter of orifice, steel penstock with vertical reach of 253m and bifurcates into the unit penstock and intermediate penstock and intermediate penstock again bifurcates into unit penstocks, three underground power house each of 80MW, air chamber of 10.7m diameter and tailrace tunnel of length 295m. HYTRAN software has been used to study hydraulic transient in the water conducting system of the project. Present study shows the effectiveness of variation of coefficient of discharge on hydraulic transient of water conducting system and on the upsurge and downsurge of the orifice type surge tank under the load rejection and acceptance on turbine. It is observed from the study height of the surge varies with the variation of coefficient of discharge