Analysis of three-dimensional numerical and experimental performance of water turbine with double blade hydrofoil

A computer-aided optimum design-analysis tool and a model was developed that can carry out all the calculations for the design of adaptable, winged water turbines and to support design decision-making processes for both high-capacity hydro-kinetic energy conversion systems for cities and smaller-scale systems for individual power demands that may efficiently operate at low current speeds. Two and three dimensional numerical and experimental analyses were conducted on double blade and also standard hydrofoil which can be used in producing electrical power from hydrokinetic energy. FLUENT and ANSYS numerical analysis programs were used in the two and three dimensional analysis respectively. The maximum values of the CL/CD and the optimum design geometric and flow parameters of models were numerically obtained. The maximum values of CL/CD is about 12,053, for double blade hydrofoil while the NACA4412 gives the CL/CD values about 21,517. Optimum angles of attacks were obtained to be 3o for doubleblade hydrofoil and 6o for the standard hydrofoil. The standard hydrofoil becomes to the stall condition after the angle of attack of 16o, while double blade becomes to the stall condition after the angle of attack about 30o respectively. The maximum power coefficient of double blade hydrofoil is about 0,457 obtained at lamda = 3,5 while the standard hydrofoil gives the maximum power coefficient of 0,494 at lamda = 5,0. Experimental studies carried out in the towing tank give the maximum power coefficient of 0,424 at lamda = 3,48 for double blade hydrofoil 0,463 at lamda = 4,92 for standard hydrofoil. There are reasonable agreements between numerical and experimental values. Comparing stall conditions, the double blade hydrofoils can operate in the range of the larger tip velocity ratio. Because of the double blade hydrofoil give maximum power lower rpm, it has more safety operation condition comparing with standart hydrofoil. Hence, the hydrokinetic turbine model for both high-capacity hydrokinetic energy conversion system for cities and smaller-scale systems for individual power demands were developed, and it is ready for prototype production and testing.