EXPERIMENTAL STUDY ON RELATIONSHIP BETWEEN SUCTION VELOCITY AND OCCURRENCE OF INTAKE VORTEX IN HORIZONTAL INTAKE

Abstract

 An intake vortex is occurred in an intake facility of a hydroelectric power station. It causes damages on a facility due to an air hammer and a reduction of power generation output. The researches have been conducted on a vertical intake of a hydroelectric power station. However, it is difficult to apply those findings in the vertical intake to other intake types such as horizontal intake directly. In this study, the hydraulic properties of horizontal intake are discussed experimentally. Suction velocities of horizontal intake pipe are changed by changing diameter of the pipe, with other conditions, ie, a flow rate, a water depth and a submergence depth are kept constant. As a result, it is found that the occurrence of the intake vortex is related to the distance between the upper edge of the horizontal pipe and the water surface and the swirl flow of the horizontal plane of near free surface is occurred at narrow regions near the left and right side of the endwall of the intake channel.