Potential for reducing kinetic energy losses in low-head hydropower installation

Abstract

Low-head hydropower plants are typically equipped with axial machines with fairly high specific speeds, with values reaching four and more in non-dimensional terms. In these installations the initial cost of equipment is an important consideration, and there is a continuing interest in increasing further the specific speed of the machines in order to reduce their size and cost. A negative aspect of the trend toward higher and higher specific speed machines is the associated decrease in turbine efficiency which is due to the increasing portion of the net head which still remains as kinetic energy of the water at the runner exit.