EXPERIMENTAL STUDY ON RELATIONSHIP BETWEEN SUBMERGENCE DEPTH OF HORIZONTAL INTAKE PIPE AND OCCURRENCE OF INTAKE VORTEX

Abstract

 A low water level operation is being carried out as one of effective utilization of existing hydroelectric power stations. In a low water level operation, a water level of a reservoir is lower than a conventional water level of a reservoir. So a submergence depth of an intake pipe is not enough, it causes an intake vortex in an intake facility of a hydroelectric power station. However, there is lack of knowledge about relationship between a submergence depth of an intake pipe and occurrence of an intake vortex in the horizontal intake facility. In this study, the hydraulic properties in horizontal intake are studied experimentally. Submergence depths of horizontal intake pipe are changed every diameter of the horizontal pipe, with other conditions, ie, a flow rate, a water depth are kept constant. As a result, it is found that the distance between the upper edge of the horizontal pipe and the water surface has a greater effect on the occurrence of vortices than the submergence depth when the upper edge of the horizontal pipe becomes shallower than half of the water depth in the intake channel.