Design and investigation of blade cascade system of an ultra-low head hydro turbine

In this research work the guide blade and runner blade cascade system of an ultra-low head hydro turbine was designed. The guide blades used are rectangular cross section flat strips, rounded smoothly at leading and trailing edges. The runner blade sections is NACA66 (mod) with a=0.8 mean line. The runner blade has varying cross section along the span. The performance of turbine was studied for the pairs of three blade runner and guide blades. A prototype ultra -low head hydro turbine of capacity 500 Watts was designed to work in head range of 1-1.3m. ANSYS (19.2), fluent code was used to compute the three dimensional flow through blade cascade. The standard two equation k-ε turbulence model was used to simulate flow though turbine blade cascade. A prototype axial flow turbine was tested laboratory. Two five hole probes were fabricated and calibrated for measuring three dimensional flow velocities in planes perpendicular to axis of rotation, located at exit to guide blades and runner. Numerical simulation results were compared with experimental results. It is observed that turbine performance was improved at high solidity ratio of guide blade cascade.