A rationalised CFD design methodology for Turgo turbines to enable local manufacture in the Global South

Butchers, Joe and Benzon, Shaun and Williamson, Sam and Booker, Julian and Aggidis, George (2021) A rationalised CFD design methodology for Turgo turbines to enable local manufacture in the Global South. Energies, 14 (Energi). ISSN 1996-1073

Abstract

In the Global South, pico- and micro-hydropower turbines are often made by local workshops. Despite several advantageous features, e.g. a high power density and capacity to handle silt, there is no commonly available Turgo turbine design appropriate for local manufacture. Technological developments including the internet, CAD and additive manufacturing increase the opportunity to precisely transfer designs around the world. Consequently, design improvements can be shared digitally and used by manufacturers in their local context. In this paper, a rationalised CFD approach is used to guide simple design changes that improve the efficiency of a Turgo turbine blade. The typical manufacturing capacity of the micro-hydropower industry in Nepal is used to rationalise the variation of potential design changes. Using the geometry and operational parameters from an existing design as a benchmark, a 2-blade homogenous multiphase model is developed and run using the commercial code ANSYS CFX. Initially, it is identified that the jet aim position has a significant effect on the efficiency. A design of experiments approach and subsequent analysis of numerical and visual results are used to make design changes that result in an improvement in efficiency from 69% to 81%. The design changes maintain the simple profile of the blade ensuring that the resulting design is appropriate for manufacture in a local workshop.