Parametric analysis of model Savonius hydrokinetic turbines through experimental and computational investigations

• Published in: Energy conversion and management 2018-02, Vol.158, p.36-49
• Main Authors: Talukdar, Parag K., Sardar, Arif, Kulkarni, Vinayak, Saha, Ujjwal K.
• Format: Article
• Language: English
• Subjects: Aspect ratio; Blade shapes, Torque coefficient; Blades; Computational fluid dynamics; Computational fluid dynamics (CFD); Computer applications; Computer simulation; Design parameters; Electric power grids; Electricity generation; Fluid dynamics; Hydrodynamics; Immersion; Irrigation canals; Mathematical models; Natural flow; Ocean currents; Parametric analysis; Parametric statistics; Power efficient; Rivers; Savonius hydrokinetic turbine (SHT); Studies; Tip-speed ratio; Turbines; Two dimensional analysis; Water currents
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2017.12.011

•Savonius hydrokinetic turbines of various blade shapes and numbers are tested.•The flow physics of the turbines are analyzed using ANSYS Fluent.•The two-bladed semicircular SHT shows highest power coefficient of 0.28.•Immersion level experiments are conducted to evaluate the performance of SHTs.•Semicircular SHT performs better than the elliptical SHT for any immersion level. The drag-based Savonius hydrokinetic turbine (SHT) has an enormous potential for small-scale power generation from free-flowing water and it can be deployed especially at sites remote from existing electricity grids. These turbines can be installed in waves, tides, ocean currents, natural flow of water in rivers, manmade channels and irrigation canals to produce power. The performance of a SHT are highly influenced by its design parameters such as blade profile, number of blades, overlap ratio and aspect ratio. Although, over a period of nine dacade since its invention, serveral studies have been carried out, however, no particular concencus on the optimum design of SHT is arrived. In view of this, in the present investigation, as attempt has been made to parametrically evaluate the performance of the SHT through experimental and computational fluid dynamics (CFD) analysis. The SHT under investigation has been developed in-house. Initially, a comparison of performance between two- and three-bladed SHT with conventional semicircular blades has been carried out experimentally where their maximum power coefficients are found to be 0.28 and 0.17, respectively at their corresponding tip-speed ratios of 0.84 and 0.67. Further experiments with a two-bladed SHT turbine with elliptical blades have shown its inferior performance as compared to the two-bladed semicircular SHT. The reason behind the enhanced performance of the two-bladed semicircular SHT is then analyzed through two-dimensional CFD simulations. Finally, the experiments are conducted at various immersion levels, where the performances of the SHTs are found to degrade with a decrease in immersion. However, the two-bladed semicircular SHT maintains to have a better performance than the others.