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

In the Global South, pico-and micro-hydropower turbines are often made by local work-shops. 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. Technologi-cal 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 was 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 was used to rationalise the variation of potential design changes. Using the geometry and operational parameters from an existing design as a benchmark, a two-blade, homogenous, multiphase model was developed and run using the commercial code ANSYS CFX. Initially, it was identified that the jet aim position had a significant effect on the efficiency. A design of experiments’ approach and subsequent analysis of numerical and visual results were used to make design changes that resulted in an improvement in efficiency from 69% to 81%. The design changes maintained the simple profile of the blade, ensuring that the resulting design was appropriate for manufacture in a local workshop