Exit Flows and Hydraulic Losses

Abstract

In order to calculate and enhance the system efficiency of a Pelton turbine, it is essential to know which hydraulic and mechanical losses exist and how they can be estimated and above all successfully reduced. The efficiency of a Pelton turbine has so far been almost exclusively determined through measurements which are either restricted to thermodynamic measurements directly taken in a power plant according to the standard IEC60041 or by model tests according to IEC60193. From such measurements, however, it is not readily possible to obtain detailed information on the effectiveness of each individual flow process in a Pelton turbine and to make statements about individual losses like swirling and exit losses, flow friction losses, mechanical windage, bearing friction losses, etc. Except for a few empirical equations pertinent to the mechanical losses, there has been hardly any available and reliable method to determine all relevant hydro-mechanical losses.