Design and Optimization of the Very Low Head Turbine by the CST Method

Utilization of hydro- power as renewable energy source is developed in the world now significantly. Using very low head axial turbines in rivers is one of ways for obtain this energy. In this research, design and optimization of an axial hydraulic turbine with very low head(2.9m) was done. The first step in the optimization of turbine is generation a suitable initial geometry. For this purpose one dimensional design approach based on Euler law was used. Development of computation algorithms is very efficient and suitable in hydraulic turbine design and performance investigation. In this research mesh was generated with mesh-ANSYS software and then the default domain was simulated by solving the 3-D Navier Stokes equations through the runner passages in the CFX software. Optimization geometry is obtained by optimization of Drag to Lift coefficient ratio for different blade midspans. For parameterization of airfoils, the “CST” method and for extraction of flow characteristics of airfoils XFOIL software were utilized. Then airfoil coefficients by minimization of Drag to Lift ratio with fminsearch algorithm in MATLAB software were corrected. The results show that the efficiency in design point is increased about 2.4%.