Browsing by Author "Shashikumar, C.M."

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Comprehensive analysis of blade geometry effects on Savonius hydrokinetic turbine efficiency: Pathways to clean energy
(Elsevier Ltd, 2024) Shanegowda, T.G.; Shashikumar, C.M.; Gumtapure, V.; Madav, V.
The rising global demand for clean and renewable energy has intensified interest in hydrokinetic energy harvesting, with Savonius turbines gaining attention due to their simplicity and low cost. While numerous studies have focused on refining blade designs for wind turbines, limited research has been conducted on water turbines to identify the best design. This study investigates the effect of blade geometry on the efficiency of Savonius hydrokinetic turbines to identify the optimal configuration. Three new blade designs were tested, incorporating inner blades and varying blade numbers. These designs were experimentally evaluated to identify the optimal turbine configuration for maximum efficiency, and the findings were then validated through numerical studies. Rotational analysis was conducted to investigate torque variations across a full turbine rotation from 0° to 360°, and flow characteristic analysis was performed by utilizing pressure and contour plots at critical positions, including 0°, minimum torque coefficient (CT Min), and maximum torque coefficient (CT Max). Results indicate that the 2-blade Savonius turbine achieved the highest efficiency, with a maximum torque coefficient of 0.29 and a power coefficient of 0.22. It demonstrated 63.5 % greater power efficiency compared to the 3-Blade Savonius Turbine, 2.65 times greater than the Segmented Quarter Savonius Turbine, and 2.26 times greater than the Concentric Arc Savonius Turbine. These findings highlight the importance of blade geometry optimization in improving the performance of Savonius turbines for efficient hydrokinetic energy generation. © 2024 The Authors
Numerical studies on the performance of Savonius hydrokinetic turbines with varying blade configurations for hydropower utilization
(Elsevier Ltd, 2024) Shanegowda, T.G.; Shashikumar, C.M.; Gumtapure, V.; Madav, V.
Hydrokinetic turbines harness the kinetic energy of flowing water to generate sustainable power, offering a promising avenue for clean and renewable energy. An effective turbine design is necessary for optimizing power extraction even in scenarios with minimal head. Among the various hydrokinetic turbine designs, the Savonius hydrokinetic turbine holds prominence. Over the past century, numerous studies have aimed to refine the design of the Savonius rotor, yet there remains no consensus on the ideal configuration for these turbines. Addressing this, the current study introduces a novel approach with detailed 3D transient simulations to enhance the water turbine performance via blade modifications, transitioning from traditional analyses that primarily focus on wind turbines. This research develops and analyzes five unique turbine geometries, each varying in blade number, diameter, and angular positions. A detailed numerical analysis was conducted using the sliding mesh technique to assess their impact on turbine efficiency and output, using an inlet water velocity of 0.5 m/s and a tip speed ratio ranging from 0.7 to 1.3. Findings indicate that a two-blade turbine configuration achieves the highest torque coefficient of 0.295, which is 2.41 times higher than that of a four-bladed design with equal blade diameter at a tip speed ratio of 0.7. It also reaches a maximum power coefficient of 0.217, marking a 155 % increase over four-bladed designs with equal blade diameter at a tip speed ratio of 0.9. © 2024 Elsevier Ltd
Performance analysis of novel V-shaped turbine blade profile by three-dimensional numerical investigations with varying overlap ratios for hydropower application
(Elsevier Ltd, 2022) Shashikumar, C.M.; Madav, V.
In the present paper, three-dimensional numerical simulations were carried out to examine the influence of the overlap ratio between the two straight edges on the advancing and returning blades of the novel V-shaped rotor blade profiles using the sliding mesh technique. The performance parameters were computed with respect to the tip speed ratio. The findings show that the coefficient of torque and power for the novel V-shaped turbine blade is maximum for the zero-overlap ratio compared to the turbine blade, with an overlap ratio ranging from 0.05 to 0.3. The blade profiles' flow field was visualized at different angular positions, and various significant zones developed during the turbine blade rotation were captured and analyzed. The new overlapping jet developed between the two straight edges of the advancing and returning blade profiles as the overlap ratio varies from 0.05 to 0.3. Therefore, the turbine's performance is reduced due to the development of an overlap jet as it travels parallel to the straight edges of the blade profile and does not impact the rear side of the returning blade profile. © 2022 Elsevier Ltd