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S V Prabhu - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigations on single stage modified Savonius Rotor
Applied Energy, 2020Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Conventional Savonius or modified forms of the conventional Savonius Rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the Rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius Rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius Rotor without central shaft between the two end plates is tested in an open jet wind tunnel. investigation is undertaken to study the effect of geometrical parameters on the performance of the Rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius Rotor with an overlap ratio of 0.0, blade arc angle of 124 degrees and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius Rotor (0.19). Correlation is developed for a single stage modified Savonius Rotor for a range of Reynolds numbers studied. (C) 200
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review on Savonius Rotor for harnessing wind energy
Wind Engineering, 2012Co-Authors: Kailash Golecha, M A Kamoji, S B Kedare, S V PrabhuAbstract:Wind machines convert kinetic energy of the wind into usable form of mechanical energy or electrical energy. The Savonius Rotor is a vertical axis wind machine which is simple in design. High starting torque characteristics make it suitable for standalone power generation as well as water pumping applications. This paper reviews the literature on the performance characteristics of the Savonius Rotor. Multi-bladed Rotor, multistage Rotor, shape of the blade, use of deflecting plate, guide vanes and nozzle augmentation are several ways to enhance the performance characteristics. This review would help an engineer in building an improved Savonius Rotor for a given application.
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experimental investigations on two and three stage modified Savonius Rotor
Wind Engineering, 2011Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Single stage modified Savonius Rotor (without shaft) is having higher coefficient of power (0.21) compared to single stage conventional Savonius Rotor (0.17). Coefficient of static torque is negative for a 1/6th of a cycle from Rotor angle 135° to 165° and from 315° to 345°. There is a large variation in the coefficient of static torque in a cycle of 180° from a peak of 0.44 at 30° to a lowest value of -0.21 at 165°. Multi-staging provides positive coefficient of static torque at all Rotor angles and reduces large variations in a cycle. Wind tunnel tests were conducted to assess the aerodynamic performance of two and three stage modified Savonius Rotors without shaft in between the end plates at different Rotor aspect ratios and stage aspect ratios. The coefficient of static torque variations decrease with the increase in the number of stages. However, the coefficient of power decreases with the increase in the number of stages. The effect of intermediate plates on the performance of Rotors is also studie...
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experimental investigations on single stage modified Savonius Rotor
Applied Energy, 2009Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Conventional Savonius or modified forms of the conventional Savonius Rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the Rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius Rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius Rotor without central shaft between the two end plates is tested in an open jet wind tunnel. Investigation is undertaken to study the effect of geometrical parameters on the performance of the Rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius Rotor with an overlap ratio of 0.0, blade arc angle of 124° and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius Rotor (0.19). Correlation is developed for a single stage modified Savonius Rotor for a range of Reynolds numbers studied.
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Performance tests on helical Savonius Rotors
Renewable Energy, 2009Co-Authors: M A Kamoji, Shireesh B. Kedare, S V PrabhuAbstract:Conventional Savonius Rotors have high coefficient of static torque at certain Rotor angles and a negative coefficient of static torque from 135° to 165° and from 315° to 345° in one cycle of 360°. In order to decrease this variation in static torque from 0° to 360°, a helical Savonius Rotor with a twist of 90° is proposed. In this study, tests on helical Savonius Rotors are conducted in an open jet wind tunnel. Coefficient of static torque, coefficient of torque and coefficient of power for each helical Savonius Rotor are measured. The performance of helical Rotor with shaft between the end plates and helical Rotor without shaft between the end plates at different overlap ratios namely 0.0, 0.1 and 0.16 is compared. Helical Savonius Rotor without shaft is also compared with the performance of the conventional Savonius Rotor. The results indicate that all the helical Savonius Rotors have positive coefficient of static torque at all the Rotor angles. The helical Rotors with shaft have lower coefficient of power than the helical Rotors without shaft. Helical Rotor without shaft at an overlap ratio of 0.0 and an aspect ratio of 0.88 is found to have almost the same coefficient of power when compared with the conventional Savonius Rotor. Correlation for coefficient of torque and power is developed for helical Savonius Rotor for a range of Reynolds numbers studied.
M A Kamoji - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigations on single stage modified Savonius Rotor
Applied Energy, 2020Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Conventional Savonius or modified forms of the conventional Savonius Rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the Rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius Rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius Rotor without central shaft between the two end plates is tested in an open jet wind tunnel. investigation is undertaken to study the effect of geometrical parameters on the performance of the Rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius Rotor with an overlap ratio of 0.0, blade arc angle of 124 degrees and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius Rotor (0.19). Correlation is developed for a single stage modified Savonius Rotor for a range of Reynolds numbers studied. (C) 200
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review on Savonius Rotor for harnessing wind energy
Wind Engineering, 2012Co-Authors: Kailash Golecha, M A Kamoji, S B Kedare, S V PrabhuAbstract:Wind machines convert kinetic energy of the wind into usable form of mechanical energy or electrical energy. The Savonius Rotor is a vertical axis wind machine which is simple in design. High starting torque characteristics make it suitable for standalone power generation as well as water pumping applications. This paper reviews the literature on the performance characteristics of the Savonius Rotor. Multi-bladed Rotor, multistage Rotor, shape of the blade, use of deflecting plate, guide vanes and nozzle augmentation are several ways to enhance the performance characteristics. This review would help an engineer in building an improved Savonius Rotor for a given application.
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experimental investigations on two and three stage modified Savonius Rotor
Wind Engineering, 2011Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Single stage modified Savonius Rotor (without shaft) is having higher coefficient of power (0.21) compared to single stage conventional Savonius Rotor (0.17). Coefficient of static torque is negative for a 1/6th of a cycle from Rotor angle 135° to 165° and from 315° to 345°. There is a large variation in the coefficient of static torque in a cycle of 180° from a peak of 0.44 at 30° to a lowest value of -0.21 at 165°. Multi-staging provides positive coefficient of static torque at all Rotor angles and reduces large variations in a cycle. Wind tunnel tests were conducted to assess the aerodynamic performance of two and three stage modified Savonius Rotors without shaft in between the end plates at different Rotor aspect ratios and stage aspect ratios. The coefficient of static torque variations decrease with the increase in the number of stages. However, the coefficient of power decreases with the increase in the number of stages. The effect of intermediate plates on the performance of Rotors is also studie...
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experimental investigations on single stage modified Savonius Rotor
Applied Energy, 2009Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Conventional Savonius or modified forms of the conventional Savonius Rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the Rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius Rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius Rotor without central shaft between the two end plates is tested in an open jet wind tunnel. Investigation is undertaken to study the effect of geometrical parameters on the performance of the Rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius Rotor with an overlap ratio of 0.0, blade arc angle of 124° and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius Rotor (0.19). Correlation is developed for a single stage modified Savonius Rotor for a range of Reynolds numbers studied.
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Performance tests on helical Savonius Rotors
Renewable Energy, 2009Co-Authors: M A Kamoji, Shireesh B. Kedare, S V PrabhuAbstract:Conventional Savonius Rotors have high coefficient of static torque at certain Rotor angles and a negative coefficient of static torque from 135° to 165° and from 315° to 345° in one cycle of 360°. In order to decrease this variation in static torque from 0° to 360°, a helical Savonius Rotor with a twist of 90° is proposed. In this study, tests on helical Savonius Rotors are conducted in an open jet wind tunnel. Coefficient of static torque, coefficient of torque and coefficient of power for each helical Savonius Rotor are measured. The performance of helical Rotor with shaft between the end plates and helical Rotor without shaft between the end plates at different overlap ratios namely 0.0, 0.1 and 0.16 is compared. Helical Savonius Rotor without shaft is also compared with the performance of the conventional Savonius Rotor. The results indicate that all the helical Savonius Rotors have positive coefficient of static torque at all the Rotor angles. The helical Rotors with shaft have lower coefficient of power than the helical Rotors without shaft. Helical Rotor without shaft at an overlap ratio of 0.0 and an aspect ratio of 0.88 is found to have almost the same coefficient of power when compared with the conventional Savonius Rotor. Correlation for coefficient of torque and power is developed for helical Savonius Rotor for a range of Reynolds numbers studied.
Ujjwal K. Saha - One of the best experts on this subject based on the ideXlab platform.
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Determining the Optimal Location of Vent Augmenters in an Elliptical-Bladed Savonius Rotor
Volume 2: Combustion Fuels and Emissions; Renewable Energy: Solar and Wind; Inlets and Exhausts; Emerging Technologies: Hybrid Electric Propulsion and, 2019Co-Authors: Nur Alom, Ujjwal K. SahaAbstract:Abstract The Savonius wind turbine Rotor, or simply Savonius Rotor is gaining importance throughout the globe as a device to produce electric power without donating much to global warming. Although this type of conventional Rotor suffers from lower efficiency, it has many important rewards like simplicity, easier manufacturability, and lower maintenance cost. This has attracted the researcher’s attention towards improving its design further. To improve the Savonius Rotor performance, several blade profiles/shapes and augmentation techniques have been evolved. In this study, an effort has been made to investigate the performance of a novel elliptical blade profile by incorporating the vent-augmentation technique. The prime objective is to decrease the negative thrust of the Rotor by locating the vents optimally on the blade concave surface. In view of this, the vents are created at three different positions on the blade concave surfaces. Two-dimensional (2D) unsteady simulations are performed around the vented blade profiles of the Savonius Rotor using SST k-ω turbulence model by FVM based solver ANSYS Fluent. The torque and power coefficients (CT and CP) are calculated at the revolving environments. The total pressure and velocity contours are obtained and analyzed. For a direct judgement, the results are also generated for the blade profiles without vent-augmenters. The study reveals an enhancement in performance of the vent-augmented elliptical blade profile of the Savonius Rotor.
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an insight into the drag and lift characteristics of modified bach and benesh profiles of Savonius Rotor
Energy Procedia, 2018Co-Authors: Nur Alom, Bastav Borah, Ujjwal K. SahaAbstract:Abstract This investigation is focused on studying the flow physics around a modified Bach and Benesh profiles of Savonius Rotor. A considerable amount of research has been done on improving the efficiency of Savonius Rotors by optimizing the various design parameters. But most of these studies concentrate on power and torque coefficients. Deeper investigation of drag and lift characteristics could result in refining the efficiency. In view of this, 2D unsteady simulations are conducted using multi-physics CFD solver to find the instantaneous forces (drag and lift) acting on the Rotors. The shear stress transport (SST) k-ω turbulence model is used for solving 2D unsteady Reynolds Averaged Navier-Stokes (RANS) equations. The total pressure, velocity magnitude and turbulence intensity contours are created at various angle of Rotor rotation. The investigation shows that the drag coefficient (CD) for the modified Bach profile is higher than the Benesh profile. The results obtained are compared with those of semicircular-profile at the identical conditions.
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Aerodynamic Performance of an Elliptical-Bladed Savonius Rotor Under the Influence of Number of Blades and Shaft
Volume 2: Structures and Dynamics; Renewable Energy (Solar Wind); Inlets and Exhausts; Emerging Technologies (Hybrid Electric Propulsion UAV ...); GT , 2017Co-Authors: Nur Alom, Nitish Kumar, Ujjwal K. SahaAbstract:In the past, various influencing parameters of the conventional semicircular-bladed Savonius Rotor such as overlap ratio, aspect ratio, number of Rotor blades have been optimized through numerical and experimental investigations to improve its performance. Furthermore, the Rotor performance under the influence of various blade profiles, shaft, endplates, and augmentation techniques has also been studied. Recent rudimentary studies with an elliptical-bladed Savonius Rotor have demonstrated its potential to harness the wind energy more efficiently; however, its influencing parameters have not been thoroughly studied and therefore they need to be optimized to arrive at a suitable design configuration. In view of this, the objective of the present investigation is to optimize the number of elliptical blades on the Rotor and then to find the influence of shaft with the optimized number of blades on the Rotor performance. For this, 2D unsteady simulation is carried out with different combinations of blades, and after having optimized the number of blades, the influence of shaft on the Rotor performance is studied. The continuity, unsteady Reynolds-Averaged Navier-Stokes (RANS) equations, and two equation eddy viscosity SST (Shear Stress transport) k-ω model are solved by using the commercial FVM based solver ANSYS Fluent. The torque and power coefficients are calculated as a function of tip speed ratio (TSR) and at rotating conditions. The total pressure, velocity magnitude, turbulence intensity and streamline patterns are obtained and analyzed to arrive at the intended objective. The numerical investigation demonstrates an improved flow characteristics and performance coefficients of the 2-elliptical-bladed profile without shaft.
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Arriving at the Optimum Overlap Ratio for an Elliptical-Bladed Savonius Rotor
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy, 2017Co-Authors: Nur Alom, Ujjwal K. SahaAbstract:The Savonius Rotor appears to be particularly promising for the small-scale applications because of its design simplicity, good starting ability, and insensitivity to wind directions. There has been a growing interest in recent times to harness wind energy in an efficient manner by developing newer blade profiles of Savonius Rotor. The overlap ratio (OR), one of the important geometric parameters, plays a crucial role in the turbine performance. In a recent study, an elliptical blade profile with a sectional cut angle (θ) of 47.5° has demonstrated its superior performance when set at an OR = 0.20. However, this value of OR is ideal for a semicircular profile, and therefore, requires further investigation to arrive at the optimum overlap ratio for the elliptical profile. In view of this, the present study attempts to make a systemic numerical study to arrive at the optimum OR of the elliptical profile having sectional cut angle, θ = 47.5°. The 2D unsteady simulation is carried out around the elliptical profile considering various overlap ratios in the range of 0.0 to 0.30. The continuity, unsteady Reynolds Averaged Navier-Stokes (URANS) equations and two equation eddy viscosity SST (Shear Stress transport) k-ω model are solved by using the commercial finite volume method (FVM) based solver ANSYS Fluent. The torque and power coefficients are calculated as a function of tip speed ratio (TSR) and at rotating conditions. The total pressure, velocity magnitude and turbulence intensity contours are obtained and analyzed to arrive at the intended objective. The numerical simulation demonstrates an improved performance of the elliptical profile at an OR = 0.15.
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review of experimental investigations into the design performance and optimization of the Savonius Rotor
Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2013Co-Authors: Ujjwal K. SahaAbstract:The Savonius Rotor is a drag-based vertical axis wind turbine and is used as an alternative source in small-scale energy generation. Design simplicity, low-cost, easy installation, good starting ability, relatively low operating speed and independent to wind directions are the main advantages of this Rotor. However, because of its low efficiency and high negative torque produced by the returning blade, this Rotor concept rarely gained popularity. Over the last few decades, although a number of investigations around the world have reported performance gains of the Savonius Rotor, the available technical design is still not able to fulfill the demand of efficient small-scale wind energy converter at low wind speeds. Until now, various design changes have been proposed to meet a growth in power output through optimization of influencing variables like aspect ratio, overlap ratio, blade material, and so forth. Investigations have also been carried out by installing additional devices like curtain design, defl...
Rajat Gupta - One of the best experts on this subject based on the ideXlab platform.
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Performance Analysis of the Helical Savonius Rotor Using Computational Fluid Dynamics
2020Co-Authors: Pinku Debnath, Rajat Gupta, Krishna Murari PandeyAbstract:The helical Savonius Rotor has a high starting torque and reasonable efficiency at low rotational speeds during start-up and is able to provide a positive coefficient of static torque at all Rotor angles. In order to improve the power and torque coefficients, a helical Savonius Rotor at different twist angles mainly 60°, 90° and 120° -is proposed. For this purpose, a helical Savonius Rotor with a shaft of 40 cm in height and 24 cm in diameter and with 60°, 90° and 120° helix angles was designed in Gambit 2.3.16. In this paper, CFD analysis of the helical shape Rotor using FLUENT 6.3 was used to predict performances such as power coefficient and torque coefficient at different tip speed ratios. Furthermore, two-bladed and threebladed helical Savonius Rotor performances were compared at 30°, 90° and 180° Rotor angles and at 0.392, 0.523, 0.785, 1.57 and 2.09 tip speed ratios. A three-dimensional unstructured grid was developed to give the best meshing accuracy as well as computational results. An RNG k-e turbulence model was used for pressure and velocity contour analysis with a standard wall function. It was con-cluded from the analysis that the highest power coefficient and torque coefficient values were obtained from a two-bladed 90° twist helical Savonius Rotor.
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experimental analysis of a 20 twist helical Savonius Rotor at different overlap conditions
Applied Mechanics and Materials, 2014Co-Authors: Rajat Gupta, Rahul Dev MisraAbstract:Wind power is a major source of sustainable energy and can be harvested using both horizontal and vertical axis wind turbines. Vertical axis wind turbines (VAWTs) accrue more popularity due to its self-starting characteristics and Omni directional in nature. Out of which Savonius Rotor is the most popular drag-based VAWT which is having lower efficiencies but having good self-starting characteristics. In order to improve the performance, helix in the tip of the blade is targeted which reduces the negative torque coefficient of the Rotor thereby could improve the performance of the Rotor. Therefore, in this paper the power coefficients of a two-bucket helical Savonius Rotor at different overlap ratios (from 0.0% to 19.76%) with helix twist angle of 20° are investigated experimentally. The investigations mainly concentrate to find out the optimum overlap ratio which is responsible for generation of maximum aerodynamic power. It is seen from the results that the power coefficient of the Rotor increases with the increase in overlap ratio up to a certain limit, and further increase of the same decreases the power coefficients. The maximum power coefficient Cp of 0.289 is obtained at an optimum overlap ratio of 12.76 %.
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Experimental Analysis of a 20° Twist Helical Savonius Rotor at Different Overlap Conditions
Applied Mechanics and Materials, 2014Co-Authors: Rajat Gupta, Rahul Dev MisraAbstract:Wind power is a major source of sustainable energy and can be harvested using both horizontal and vertical axis wind turbines. Vertical axis wind turbines (VAWTs) accrue more popularity due to its self-starting characteristics and Omni directional in nature. Out of which Savonius Rotor is the most popular drag-based VAWT which is having lower efficiencies but having good self-starting characteristics. In order to improve the performance, helix in the tip of the blade is targeted which reduces the negative torque coefficient of the Rotor thereby could improve the performance of the Rotor. Therefore, in this paper the power coefficients of a two-bucket helical Savonius Rotor at different overlap ratios (from 0.0% to 19.76%) with helix twist angle of 20° are investigated experimentally. The investigations mainly concentrate to find out the optimum overlap ratio which is responsible for generation of maximum aerodynamic power. It is seen from the results that the power coefficient of the Rotor increases with the increase in overlap ratio up to a certain limit, and further increase of the same decreases the power coefficients. The maximum power coefficient Cp of 0.289 is obtained at an optimum overlap ratio of 12.76 %.
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performance measurement of a two stage two bladed Savonius Rotor
International Journal of Renewable Energy Research, 2014Co-Authors: Kaushal Kumar Sharma, Rajat Gupta, Agnimitra BiswasAbstract:Conventional Savonius Rotor is the ancient form of Vertical Axis Wind Turbines (VAWT) Rotor which has many advantages such as self-starting, omni-directional, less noisy, suitability for applications like pumping, grinding, sailing etc. However, its efficiency is only in the range of 15%-21%. Investigations are being conducted to improve its efficiency by controlling its design parameters. In this paper the performance of a two-stage two-bladed configuration of the Savonius Rotor has been investigated. Experiments are conducted in a subsonic wind tunnel available in the department. The parameters studied are overlap, tip speed ratio, power coefficient (Cp) and torque coefficient (Ct). Overlap ratio of the design was optimized to generate maximum performance of the Rotor. The study showed that a maximum Cp of 0.517 was obtained at 9.37% overlap condition. Thus Cp of the Rotor is much higher than the conventional Savonius Rotor.
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performance measurement of a three bladed combined darrieus Savonius Rotor
International Journal of Renewable Energy Research, 2013Co-Authors: Kaushal Kumar Sharma, Agnimitra Biswas, Rajat GuptaAbstract:Combination of Savonius and Darrieus type Vertical Axis Wind Turbine (VAWT) Rotors possess many advantages over their individual designs, like low starting torque, high power coefficient, low cut-in wind speed etc. However, there is still a need to do more research on such combination of Rotors for their viability in the built environment where wind speed is low. In this paper, an attempt is made to measure the performance of a three-bladed combined Darrieus-Savonius Rotor, with Darrieus mounted on top of Savonius Rotor, for overlap variations from 10.8% to 25.8%. Power coefficients (C p ) and torque coefficients (C t ) were calculated in a low range of Tip Speed Ratio for each overlap condition. It is found that C p increases with the increase of overlap. However, there is an optimum value of overlap for which, C p is maximum, beyond this, C p starts decreasing. The similar trend is observed for C t as well. The maximum C p of 0.53 is obtained at 0.604 Tip Speed Ratio (TSR) for an optimum 16.8% overlap. The performance of the Rotor is also compared with another version of this hybrid design with Savonius mounted on top of Darrieus Rotor. The present Darrieus-Savonius Rotor can be suitably placed in the built environment where it can harness more power from wind and, at the same time, would self-start in low wind condition prevalent in such environment.
S B Kedare - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigations on single stage modified Savonius Rotor
Applied Energy, 2020Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Conventional Savonius or modified forms of the conventional Savonius Rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the Rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius Rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius Rotor without central shaft between the two end plates is tested in an open jet wind tunnel. investigation is undertaken to study the effect of geometrical parameters on the performance of the Rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius Rotor with an overlap ratio of 0.0, blade arc angle of 124 degrees and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius Rotor (0.19). Correlation is developed for a single stage modified Savonius Rotor for a range of Reynolds numbers studied. (C) 200
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review on Savonius Rotor for harnessing wind energy
Wind Engineering, 2012Co-Authors: Kailash Golecha, M A Kamoji, S B Kedare, S V PrabhuAbstract:Wind machines convert kinetic energy of the wind into usable form of mechanical energy or electrical energy. The Savonius Rotor is a vertical axis wind machine which is simple in design. High starting torque characteristics make it suitable for standalone power generation as well as water pumping applications. This paper reviews the literature on the performance characteristics of the Savonius Rotor. Multi-bladed Rotor, multistage Rotor, shape of the blade, use of deflecting plate, guide vanes and nozzle augmentation are several ways to enhance the performance characteristics. This review would help an engineer in building an improved Savonius Rotor for a given application.
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experimental investigations on two and three stage modified Savonius Rotor
Wind Engineering, 2011Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Single stage modified Savonius Rotor (without shaft) is having higher coefficient of power (0.21) compared to single stage conventional Savonius Rotor (0.17). Coefficient of static torque is negative for a 1/6th of a cycle from Rotor angle 135° to 165° and from 315° to 345°. There is a large variation in the coefficient of static torque in a cycle of 180° from a peak of 0.44 at 30° to a lowest value of -0.21 at 165°. Multi-staging provides positive coefficient of static torque at all Rotor angles and reduces large variations in a cycle. Wind tunnel tests were conducted to assess the aerodynamic performance of two and three stage modified Savonius Rotors without shaft in between the end plates at different Rotor aspect ratios and stage aspect ratios. The coefficient of static torque variations decrease with the increase in the number of stages. However, the coefficient of power decreases with the increase in the number of stages. The effect of intermediate plates on the performance of Rotors is also studie...
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experimental investigations on single stage modified Savonius Rotor
Applied Energy, 2009Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:Conventional Savonius or modified forms of the conventional Savonius Rotors are being investigated in an effort to improve the coefficient of power and to obtain uniform coefficient of static torque. To achieve these objectives, the Rotors are being studied with and without central shaft between the end plates. Tests in a closed jet wind tunnel on modified form of the conventional Savonius Rotor with the central shaft is reported to have a coefficient of power of 0.32. In this study, modified Savonius Rotor without central shaft between the two end plates is tested in an open jet wind tunnel. Investigation is undertaken to study the effect of geometrical parameters on the performance of the Rotors in terms of coefficient of static torque, coefficient of torque and coefficient of power. The parameters studied are overlap ratio, blade arc angle, aspect ratio and Reynolds number. The modified Savonius Rotor with an overlap ratio of 0.0, blade arc angle of 124° and an aspect ratio of 0.7 has a maximum coefficient of power of 0.21 at a Reynolds number of 1,50,000, which is higher than that of conventional Savonius Rotor (0.19). Correlation is developed for a single stage modified Savonius Rotor for a range of Reynolds numbers studied.
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experimental investigations on single stage two stage and three stage conventional Savonius Rotor
International Journal of Energy Research, 2008Co-Authors: M A Kamoji, S B Kedare, S V PrabhuAbstract:The performance of single stage (Rotor aspect ratio of 1.0), two stage Savonius Rotor with Rotor aspect ratios of 1.0 and 2.0 (stage aspect ratios of 0.50 and 1.0) and three stage Savonius Rotor with Rotor aspect ratios of 1.0 and 3.0 (stage aspect ratios of 0.33 and 1.0) are studied at different Reynolds numbers and compared at the same Reynolds number. The results show that the coefficient of power and the coefficient of torque increase with the increase in the Reynolds numbers for all the Rotors tested. The coefficient of static torque is independent of the Reynolds number for all the Rotors tested. The performance of two stage and three stage Rotors remains the same even after increasing the stage aspect ratio and the Rotor aspect ratio by a factor of two and three, respectively. For the same Rotor aspect ratio of 1.0, by increasing the number of stages (stage aspect ratio decreases), the performance deteriorates in terms Cp and Ct. However, at the same stage aspect ratio of 1.0 and same Reynolds number, two and three stage Rotors show the same performance in terms of coefficient of power and coefficient of torque. The variation in coefficient of static torque is lower for a three stage Rotor when compared with the variation of coefficient of static torque for two stage or single stage Rotor. Copyright © 2008 John Wiley & Sons, Ltd.
