Characteristics of a micro-hydro turbine

Computational Fluid Dynamics, a crucial tool in exploring designs of hydraulic machinery, is used to evaluate the design of a non-uniform Archimedean spiral rotor. A transient simulation method is implemented using a frame of reference change between time-steps to capture the flow field correctly. The boundary conditions for this method are discussed and are validated with previously published experimental data using a flat plate propeller turbine. A spectral and temporal convergence study for the non-uniform Archimedean spiral rotor is performed to verify solution independence of mesh and time-step selection. Performance characteristics of the rotor are provided over a wide range of volumetric flow rates and rotation rates. The best hydraulic efficiency point is determined to be 72% for the presented rotor design and is compared with the performance of similar micro-hydro turbines.