Numerical study of different models of an Agnew micro hydro turbine

In this study, a three-dimensional fluid field of an axial flow type micro hydro named Agnew has been investigated. The turbine installed at the Hydrulic Machines Laboratory (HML) of Iranian Research Organization for Science and Technology has been designed to generate 1 kw output power.All numerical simulations were performed using ANSYS CFX, a Computational Fluid Dynamic code, to investigate the performance parameters, such as efficiency and power, and results are validated against experimental data. Four different grid sizes are studied in accordance with the Grid Convergence Index (GCI) to investigate mesh independency of the solution. Results of several turbulence models were also examined to find out the Shear Stress Transport (SST) model in order to take into account the turbulence in the flow. Several turbulence models were also examined together with wall function in order to take into account the turbulence in the flow. A mixing plane interface plane was used to pass the disturbance of rotary domain to stationary domain. The obtained results show that a high resolution advection scheme, mixing plane to model the rotor-stator interaction together with a turbulence intensity of I=6% at the inlet, best matches with the experimental results. The difference between the efficiencies computed from both numerical approaches and experimental values may be ascribed to a numerical error, a model error or a systematic error.