scholarly journals Experimental Study of Darrieus-Savonius Water Turbine with Deflector: Effect of Deflector on the Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Kaprawi Sahim ◽  
Kadafi Ihtisan ◽  
Dyos Santoso ◽  
Riman Sipahutar
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Performance Characteristics ◽  
Power Coefficient ◽  
Irrigation Canal ◽  
Savonius Rotor ◽  
Water Turbine ◽  
Darrieus Rotor ◽  
Deflector Plate

The reverse force on the returning blade of a water turbine can be reduced by setting a deflector on the returning blade side of a rotor. The deflector configuration can also concentrate the flow which passes through the rotor so that the torque and the power of turbine can be considerably increased. The placing of Savonius in Darrieus rotor is carried out by setting the Savonius bucket in Darrieus rotor at the same axis. The combination of these rotors is also called a Darrieus-Savonius turbine. This rotor can improve torque of turbine. Experiments are conducted in an irrigation canal to find the performance characteristics of presence of deflector and Savonius rotor in Darrieus-Savonius turbine. Results conclude that the single deflector plate placed on returning blade side increases the torque and power coefficient. The presence of Savonius rotor increases the torque at a lower speed, but the power coefficient decreases. The torque and power coefficient characteristics depend on the aspect ratio of Savonius rotor.

scholarly journals Performance Study of Modified Savonius Water Turbine with Two Deflector Plates

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Golecha Kailash ◽  
T. I. Eldho ◽  
S. V. Prabhu
Keyword(s):  
Driving Force ◽  
Lower Cost ◽  
Vertical Axis ◽  
Performance Study ◽  
Optimal Position ◽  
Savonius Rotor ◽  
Optimum Position ◽  
Water Turbine ◽  
Deflector Plate ◽  
Positive Force

Savonius rotor is a vertical axis rotor with simple in design and easy to fabricate at lower cost. The rotation of the rotor is due to the drag difference between the advancing blade and returning blade. Net driving force can be increased by reducing the reverse force on the returning blade or increasing the positive force on the advancing blade. Former can be realized by providing a flow obstacle to the returning blade and latter can be realized by concentrating the flow towards the advancing blade. The objective of the present work is to identify the optimal position of the deflector plate (on advancing blade side) placed upstream to the flow which would result in increase in power generated by the rotor. Tests are conducted to identify the optimum position of the deflector plate on the advancing blade side in the presence of a deflector plate on the returning blade side at its optimum position. Results suggest that two deflector plates placed at their optimal positions upstream to the flow increase the coefficient of power to 0.35. This is significantly higher than the coefficient of power of 0.14 observed for the rotor without deflector plates.

scholarly journals Performance of Combined Water Turbine with Semielliptic Section of the Savonius Rotor

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Kaprawi Sahim ◽  
Dyos Santoso ◽  
Agus Radentan
Keyword(s):  
Stream Flow ◽  
Free Stream ◽  
Irrigation Canal ◽  
Savonius Rotor ◽  
Important Variation ◽  
Turbine Performance ◽  
Water Turbine ◽  
Naca 0015 ◽  
Starting Torque ◽  
Suitable Power

The Darrieus turbine is a suitable power generation in free stream flow because it is simple in construction, but it has the disadvantage of its small starting torque. The Savonius turbine has a high starting torque but the efficiency is smaller than that of Darrieus turbine. To improve the starting torque of Darrieus turbine, the Savonius buckets are introduced into the Darrieus turbine and the combined turbine is called Darrieus-Savonius turbine. In this study, three semielliptic sections of aspect ratio 0.8 were used for Savonius bucket while the Darrieus blade used three wings of airfoil NACA 0015. The Darrieus-Savonius turbine’s performances were studied experimentally in an irrigation canal of South Sumatera, Indonesia. The results show that the distance of Savonius buckets from the shaft centre influences performance of combined turbine, and the attachment angle of Savonius rotor made important variation of turbine performance.

scholarly journals Numerical study of savonius water turbine performance by adding deflector to advancing blade side

2018 ◽  
Author(s):  
Priyo Agus Setiawan ◽  
Anda Iviana Juniani ◽  
Adi Wirawan Husodo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Study ◽  
Renewable Energy Sources ◽  
Power Coefficient ◽  
Turbine Performance ◽  
Water Turbine ◽  
Unsteady Rans ◽  
Deflector Plate ◽  
Coarse To Fine

As one of the best renewable energy sources, hydropower becomes more predictable sourcecompared to wind energy and Savonius which its performance does not contingent to fluid flowdirection. In this present, computational Fluid Dynamics acomplished by Finite Volume Methodand unsteady RANS equation were applied to analyze the numerical simulation. The presentstudy investigated the performance of Savonius Turbine by adding deflector plate installed toadvancing blade side at 5, 10, 15, 30 and 45 of deflector angles in the direction of the fluid flow.The viscous turbulence model used realizable k-epsilon (RKE) and its descritization usedsecond order upwind. The type of mesh was made from coarse to fine meshing with 8 (eight)types of meshing and the grid independency of the numerical simulation had been validated bythe publish experimental data at TSR of 1,078. Grid independency occured at meshing G withthe error lower than 5 % compared to published experimental data. The result of this studyshows that the performance of Savonius turbine increased by adding deflector in advancingblade side with the maximum torque and power coefficient at 30 of deflector angle.

scholarly journals Computational Optimization of Adaptive Hybrid Darrieus Turbine: Part 1

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 90 ◽  
Author(s):  
Palanisamy Mohan Kumar ◽  
Mohan Ram Surya ◽  
Krishnamoorthi Sivalingam ◽  
Teik-Cheng Lim ◽  
Seeram Ramakrishna ◽  
...  
Keyword(s):  
Numerical Study ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Small Scale ◽  
Past Study ◽  
Savonius Rotor ◽  
Computational Optimization ◽  
Darrieus Rotor ◽  
Low Efficiency ◽  
The Impact

Darrieus-type Vertical Axis Wind Turbines (VAWT) are promising for small scale decentralized power generation because of their unique advantages such as simple design, insensitive to wind direction, reliability, and ease of maintenance. Despite these positive aspects, poor self-starting capability and low efficiency in weak and unsteady winds deteriorate further development. Adaptive Hybrid Darrieus Turbine (AHDT) was proposed by the author in the past study as a potential solution to enhance low wind speed characteristics. The objective of the current research is to optimize the parameters of AHDT. AHDT integrates a dynamically varying Savonius rotor with a Darrieus rotor. A fully detailed 2D numerical study employing Reynold-Averaged Navier Stokes (RANS) is carried out to investigate the impact of the Darrieus rotor diameter (DR) on the Savonius rotor (DT) with regard to hybrid turbine performance. The power coefficient of the Darrieus rotor is evaluated when the Savonius rotor is in the closed condition (cylinder) of various diameters. The influence of Reynolds number (Re) on the torque coefficient is examined. Power loss of 58.3% and 25% is reported for DR/DT ratio of 1.5 and 2 respectively for AHDT with solidity 0.5 at 9 m/s. The flow interaction between the Savonius rotor in closed configuration reveals the formation of von Karman vortices that interact with Darrieus blades resulting in flow detachment. An optimum diametrical ratio (DR/DT) of 3 is found to yield the maximum power coefficient of the Darrieus rotor.

Experimental Study of CD Variation With Aspect Ratio

1999 ◽  
Author(s):  
Jack Williams ◽  
Jewel Barlow ◽  
Robert Ranzenbach
Keyword(s):  
Experimental Study ◽  
Aspect Ratio

NUMERICAL AND EXPERIMENTAL STUDY ON FREE VIBRATION OF DELAMINATED WOVEN FIBER GLASS/EPOXY COMPOSITE PLATES

2012 ◽  
Vol 12 (02) ◽  
pp. 377-394 ◽  
Author(s):  
J. MOHANTY ◽  
S. K. SAHU ◽  
P. K. PARHI
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Natural Frequencies ◽  
Numerical Study ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Fiber Glass ◽  
Number Of Layers

This paper presents a combined experimental and numerical study of free vibration of industry-driven woven fiber glass/epoxy (G/E) composite plates with delamination. Using the first-order shear deformation theory, an eight-noded two-dimensional quadratic isoparametric element was developed, which has five degrees of freedom per node. In the experimental study, the influence of various parameters such as the delamination size, boundary conditions, fiber orientations, number of layers, and aspect ratio on the natural frequencies of delaminated composite plates are investigated. Comparison of the numerical results with experimental ones shows good agreement. Fundamental natural frequencies are found to decrease with the increase in the delamination size and fiber orientation and increases with the increase in the number of layers and aspect ratio of delaminated composite plates. The natural frequency of the delaminated composite plate varies significantly for different boundary conditions.

Performance study of twisted Darrieus hydrokinetic turbine with novel blade design

2021 ◽  
pp. 1-37
Author(s):  
Mabrouk Mosbahi ◽  
Mouna Derbel ◽  
Mariem Lajnef ◽  
Bouzid Mosbahi ◽  
Zied Driss ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Maximum Power ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Small Scale ◽  
Performance Study ◽  
Hydrokinetic Turbine ◽  
Blade Shape ◽  
Water Turbine ◽  
Water Canals

Abstract Twisted Darrieus water turbine is receiving growing attentiveness for small-scale hydropower generation. Accordingly, the need for raised water energy conversion incentivizes researchers to focalise on the blade shape optimization of twisted Darrieus turbine. In view of this, an experimental analysis has been performed to appraise the efficiency of a spiral Darrieus water rotor in the present work. To better the performance parameters of the studied water rotor with twisted blades, three novel blade shapes, namely U-shaped blade, V-shaped blade and W-shaped blade, have been numerically tested using a computational fluid dynamics three-dimensional numerical model. Maximum power coefficient of Darrieus rotor reaches 0.17 at 0.63 tip-speed ratio using twisted blades. Using V-shaped blades, maximum power coefficient has been risen up to 0.185. The current study could be practically applied to provide more effective employment of twisted Darrieus turbines and to improve the generated power from flowing water such as river streams, tidal currents, or other man made water canals.

Yacht Keels - An Experimental Study

1975 ◽  
Author(s):  
Pierre DeSaix
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Center Of Gravity ◽  
Full Scale ◽  
Optimum Size ◽  
Hull Form ◽  
Size And Shape ◽  
Aspect Ratios ◽  
Current Design ◽  
Lateral Area

Model tests are presented for a series of nine keels; three aspect ratios, three sweep angles; all at constant lateral area, taper ratio and thickness ratio. The series is shown to bracket current design trends. These keels are all tested on the same canoe body, over a range of heel angles, lee-ways, and speeds. The results are presented in terms of full-scale sailing performance with due allowance for a reasonable ballast ratio and resulting vertical center of gravity for each keel. Optimum sweep angles for each aspect ratio are found. A second series of three keels, geometrically similar but varying in lateral area, is provided. Predictions of windward performance demonstrate the effect of keel size. An optimum size is found for three wind strengths. The results are for one hull form only. However, a method is suggested for estimating the effect of keel size and shape for any proposed design.

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