Evaluation of energy loss in a low-head axial flow turbine under different blade numbers using entropy production method

Abstract

The internal flow loss characteristics of axial flow turbines (AFT), which are often utilized to generate hydropower, have not yet been completely explored. The flow loss characteristics of the turbine under varied blade numbers (z = 2, z = 3, and z = 4) are examined in this work using a low head AFT as the research object using a combination of entropy production theory and numerical simulation. According to a thorough investigation of entropy generation, the majority of energy losses occur downstream in the wake zone, at the flow channel's edge, and close to the blade tip. The major source of entropy production in the turbine is turbulent dissipation. The findings showed that as the number of blades increased, energy loss decreased. At the leading edge and flow cascade when z = 2 at the design flow rate, peak turbulence dissipation of 581 W/m3 and 39.11 W/m-3 were measured. On the other hand, z = 4 had the lowest levels of dissipation. The optimal blade number, according to the case studies, is z = 4, since it has the lowest energy loss and most efficiency.