Application of laser doppler velocimetry to the development of a counter rotating micro-turbine

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Elena Vagnoni, Loïc Andolfatto, João Delgado, Cécile Münch-Alligné, François Avellan

Tuesday 30 june 2015

14:35 - 14:50h at Africa (level 0)

Themes: (T) Water engineering, (ST) Experimental facilities and instrumentation

Parallel session: 6F. Engineering - Instrumentation

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The production of hydraulic energy is the most widely used form of renewable energy, accounting for 16% of global electricity generation, and it is expected to increase about 3.1% each year for the next 25 years. Hydro electricity is a competitive source of renewable electricity due to its relatively low cost that has been cut down with the installation of new technologies. In particular the sustainability of small scale hydro power production can be improved with the development of energy recovery systems on the water utilities. The concept of the new counter rotating micro-turbine presented in this work is a competitive option for energy recovery on water utility networks. The micro-turbine performances and velocity fields have been predicted through a wide Computational Fluid Dynamics (CFD) study. Experimental campaigns have been carried out to measure the performance parameters and an experimental investigation on the flow velocity field characteristic of the new machine were also performed. 2D Laser Doppler Velocimetry (LDV) measurements have been performed on the counter rotating micro-turbine prototype operating in water in order to explore and verify the predicted flow velocity field. A dedicated casing has been designed. It is made out of transparent acrylic equipped with flat glass windows in order to minimize the laser beams distortion during the LDV measurements from different positions. The axial and tangential velocity components have been investigated at several radial positions in the inlet, inter-wheels and outlet section of the runners. The result achieved allows a better understanding of the flow behavior. It also increases the robustness of both the numerical simulation and the associated micro-turbine optimization.