Numerical Investigation of Hydroturbine Performance Using Immersed-Boundary Method

Abstract

Flow in a special designed hydro turbine was simulated using the immersed-boundary method 1 . Thanks to the immersed-boundary method, the complicated flow-driven motion of the turbine components can be simulated. The Smagorinsky-Lilly turbulence model was implemented in order to simulate the practical high-Reynolds number cases. The turbine performance criteria, such as rpm and power output, were studied and compared among different configurations to obtain the optimal design. The different design configurations considered in this study include the casing inlet length and angle, and w/o casing. The detailed flow physics inside the turbine which causes the complex turbine-blade motion is also discussed in this paper. Nomenclatureu = velocity P = pressure ν = kinematic viscosity t ν = turbulence kinematic viscosity f = body force Cs = Smagorinsky constant t = time ∆ = filter width Sij = Instantaneous strain-rate tensor F = surface force on blade T = moment on rotor n = number of blades α = angular acceleration ω = angular velocity θ = moved angle