Numerical simulation of the updraft free-exit-flow hydropower turbine system

CFD method and ICEM FLUENT commercial software were used to do numerical simulation of three-dimensional flow in the updraft free-exit-flow hydropower turbine system. The time-averaged Navier-Stokes equations were used in the calculation, standard k-ε turbulent model and SIMPLEC algorithm were chosen for the simulation, it provides pressure and velocity vector distribution inside the spiral-case and runner, meanwhile it gives good results in terms of its power production efficiency, about 86%. The numerical simulation results show that, there are major improvements in design of updraft free-exit-flow, such as decreasing internal turbine flow turbulence, lessening strength requirement of the support structure, simplifying flow control mechanism, and minimizing environmental and ecological disturbances.