PNNL

Abstract

Small hydropower applications with ultralow heads are abundantly available and present minimal environmental and ecological impacts compared to large-scale hydropower projects. However, little attention has been paid to them because of the low power-to-weight ratios of small turbines. Aiming to resolve this issue, this study investigated the possibility of using light-weight composite materials to replace stainless steel (SS) as the turbine runner material by evaluating a Propeller-type composite blade theoretically and experimentally relative to its SS counterpart. Flow analyses of the SS and the composite blades were conducted. The pressure profiles obtained were applied to the computer-aided design models of the blades to conduct stress analyses of three different composite material candidates using finite element methods. Based on the simulation results, a prototype of the composite blade was fabricated and tested in a lab-scale turbine performance test loop to compare its performance to that of the SS blade. At the same flow rates, the turbine with the composite blade was found to generate more power at a slightly higher head than the turbine with the SS blade. Both turbines displayed similar peak turbine efficiencies, demonstrating the viability of the composite material in replacing SS from the power-generation performance perspective.