Design and performance optimization of a very low head turbine with high pitch angle based on two-dimensional optimization

Abstract

Very low head (VLH) axial hydro turbines are efficient turbomachinery to harness energy from tidal or river currents and increase renewable energy penetration in the world’s electric power generation. In this paper, the initial design of a VLH turbine with high pitch blade is optimized. The class function/shape function transformation method is applied along with a coupling of XFOIL with a MATLAB code to find optimum blade profiles with minimum drag-to-lift ratio. SST k–ω turbulence model is implemented to solve three-dimensional (3D) continuity and RANS equations by considering homogeneous multiphase model with standard free surface flow. The numerical results are validated against available experimental measurements, and the optimization results are discussed. The numerical results indicated that efficiency and power of the VLH turbine at the design point increased by 2.4% and 7.7 kW, respectively. Analyzing pressure distribution on suction and pressure sides of runner blades showed no occurrence of cavitation in operating condition of the turbine.