Numerical simulation of the flow and output of a Savonius hydraulic turbine using the lattice Boltzmann method

Abstract

The flow and output of a Savonius hydraulic turbine rotor were simulated using the lattice Boltzmann method (LBM). The rotor, characterized by a configuration featuring two semi-circular arc-shaped blades, operated at a Reynolds number of 1.1 × 105. The simulations were conducted in a two-dimensional domain, focusing on the incompressible flow within the cross-sectional area of the rotor perpendicular to its rotational axis. The LBM approach was coupled with a rotor rotation analysis. In the LBM framework, the non-orthogonal central moment model was employed for the precise computation of particle collisions. Additionally, the direct forcing method was used to consider the rotating blades and shaft. Consequently, the torque exerted on both advancing and returning blades and rotor output was successfully simulated. These simulations unveiled the inherently unsteady rotational behavior of the rotor, stemming from the variable torque acting upon the blades. Moreover, the computational results exhibited a notable agreement between the simulated flow pattern around the rotor and the experimental visualization. Furthermore, an approximately identical correlation between the rotor speed and power output was established, mirroring the experimental results. These findings underscore the robust applicability of LBM in facilitating the design and operational analysis of Savonius hydraulic turbines.