Design and Performance Testing of a Ducted Savonius Turbine for Marine Current Energy Extraction

2013 ◽  
Author(s):  
Jai N. Goundar ◽  
Deepak Prasad ◽  
Mohammed Rafiuddin Ahmed
Keyword(s):  
Flow Characteristics ◽  
Performance Testing ◽  
Maximum Efficiency ◽  
Speed Ratio ◽  
Stream Velocity ◽  
Water Stream ◽  
Ansys Cfx ◽  
Marine Current ◽  
And Performance ◽  
Current Energy

Marine current energy is a reliable and clean source of energy. Several marine current turbines have been developed over the years, most of the turbines perform well at velocities over 2 m/s and need to be installed at depths of 20–40 m. Placing an appropriately designed duct or shroud around the turbine significantly improves the turbine’s performance. Ducted Savonius turbines can operate at low depths, since large clearance is not required because turbulent flow has little effect on the performance of the Savonius rotor. Ducted Savonius turbine has simple components and can be easily fabricated in Pacific Island Countries (PIC) and other places that do not have advanced manufacturing industries. A ducted Savonius turbine was designed for a location in Fiji, to operate at a rated marine current speed of 1.15 m/s and cut in speed of 0.2 m/s. The model of ducted Savonius turbine, scaled down to 1/20, was fabricated and tested in a water stream with a velocity of 0.6 m/s and was validated with commercial Computational Fluid Dynamics (CFD) code ANSYS-CFX. Finally, a full scale numerical model was constructed to study the flow characteristics and compute the performance. The area ratio of the duct of 2.5:1 (inlet to turbine section) shows significant increase in kinetic energy and an improved turbine performance. The maximum efficiency of the turbine is around 50% at a tip speed ratio (TSR) of 3.5 and the maximum power produced is 10 kW at the rated speed of 1.15 m/s and 63.4 kW at a free-stream velocity of 2.15 m/s.

Design and Optimization of a Ducted Marine Current Savonius Turbine for Gun-Barrel Passage, Fiji

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Jai Nendran Goundar ◽  
M. Rafiuddin Ahmed ◽  
Young-Ho Lee
Keyword(s):  
Flow Characteristics ◽  
Maximum Efficiency ◽  
Speed Ratio ◽  
Water Stream ◽  
Freestream Velocity ◽  
Design And Optimization ◽  
Gun Barrel ◽  
Marine Current ◽  
Ducted Turbine ◽  
Shaft Power

Marine current energy is a reliable and clean source of energy. Many marine current turbines have been designed and developed over the years. Placement of an appropriately designed duct or shroud around the turbine significantly improves the turbine performance. In the present work, a ducted Savonius turbine (DST) is designed and optimized and its performance analysis carried out. The components of DSTs are simple and easily available and can be manufactured in developing countries like Fiji. A scaled-down model of 1/20 of a DST was fabricated and tested in a water stream at a velocity of 0.6 m/s and the results were used to validate the results from a commercial computational fluid dynamics (CFD) code ANSYS-cfx. Finally, a full-scale DST was modeled to study the flow characteristics in the turbine and the performance characteristics. The maximum efficiency of the turbine is around 50% at the tip speed ratio (TSR) of 3.5 and the maximum shaft power obtained is 10 kW at the rated speed of 1.15 m/s and around 65 kW at a freestream velocity of 2.15 m/s. The stress distribution on the ducted turbine was also obtained.

Design of a Ducted Cross Flow Turbine for Fiji

2015 ◽  
Vol 772 ◽  
pp. 561-565
Author(s):  
Jai Nendran Goundar ◽  
Niranjwan Chettiar ◽  
Sumesh Narayan ◽  
Ashneel Deo ◽  
Deepak Prasad
Keyword(s):  
Energy Source ◽  
Alternative Energy ◽  
Fossil Fuel ◽  
Fluid Dynamic ◽  
Cross Flow ◽  
Maximum Efficiency ◽  
Maintenance Cost ◽  
Ansys Cfx ◽  
Marine Current ◽  
Current Energy

Marine current energy is clean and reliable energy source. It can be alternative energy source to produce electricity if tapped with a suitable marine current energy converter. Pacific Island countries (PIC) like Fiji can reduce the amount of Fossil fuel used. However for most energy converters designed perform well at marine current velocities above 2m/s and it needs to be installed at depths of 20 – 40m also installation and the maintenance cost of such devise will be quite high if it needs to be installed in Fiji. Therefore a ducted cross flow turbine was designed, which can give desired output at minimum installation and maintenance cost. A dusted cross flow turbine has been design taking into account for its operating condition. The turbine was modelled and analyzed in commercial; Computational Fluid dynamic (CFD) code ANSYS-CFX. The code was first validated and with experiment results and finally performance analysis of full scale turbine was carried out. The designed turbine can have maximum efficiency of 56% producing rated power of 21kW; it produces 0.77kW at cut in speed of 0.65m/s.

Effect of Diagonal Layout on Efficiency of Twin Vertical Axis Turbine

2013 ◽  
Vol 773 ◽  
pp. 203-206
Author(s):  
Ke Sun ◽  
Shah Khalid Syed ◽  
Liang Zhang ◽  
Sahib Ghazala
Keyword(s):  
Vertical Axis ◽  
Maximum Efficiency ◽  
Incoming Flow ◽  
Tidal Current Energy ◽  
Ansys Cfx ◽  
Tidal Turbine ◽  
Vertical Axis Turbine ◽  
Current Flows ◽  
Vertical Axis Tidal Turbine ◽  
Current Energy

Vertical axis turbine is one of the tools used to extract tidal current energy. The purpose of this study is to show the effect of diagonal layout on the efficiency of vertical axis tidal turbine (VATT), using commercial software ANSYS CFX. For this purpose the angle between the incoming current flows is varied while the distance between the turbines is kept constant. The layout is observed at an angle of 200, 300, 450, 600and 900. From study we observed that when the twin turbines are at angle of 900to the incoming flow, the turbines have maximum efficiency.

A New Device for Increasing Output of Marine Current Energy

2013 ◽  
Vol 291-294 ◽  
pp. 1989-1992
Author(s):  
Zhi Yong Dong ◽  
Xu Zhang ◽  
Li Wang ◽  
Bin Shi
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
Area Ratio ◽  
Diameter Ratio ◽  
Stream Velocity ◽  
New Device ◽  
University Of Technology ◽  
Marine Current Turbine ◽  
Marine Current ◽  
Current Energy

In this paper, a speeding-up inlet was developed to increase the free stream velocity in the marine current in order to increase the input energy of turbine. This study was conducted in the Hydrodynamics Laboratory at Zhejiang University of Technology. By using high-speed camera, acoustic Doppler velocimetry (ADV), the influence of area ratio and length-diameter ratio on rotational speed of the turbine was experimentally investigated. Experimental results showed that both area ratio and length-diameter ratio have significant influences on the rotational speed of marine current turbine.

scholarly journals Validation of a Coupled Electrical and Hydrodynamic Simulation Model for a Vertical Axis Marine Current Energy Converter

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3067 ◽  
Author(s):  
Johan Forslund ◽  
Anders Goude ◽  
Karin Thomas
Keyword(s):  
Experimental Data ◽  
Simulation Model ◽  
Synchronous Generator ◽  
Vertical Axis ◽  
Step Response ◽  
Speed Ratio ◽  
Direct Drive ◽  
Vortex Model ◽  
Marine Current ◽  
Current Energy

This paper validates a simulation model that couples an electrical model in Simulink with a hydrodynamic vortex-model by comparing with experimental data. The simulated system is a vertical axis current turbine connected to a permanent magnet synchronous generator in a direct drive configuration. Experiments of load and no load operation were conducted to calibrate the losses of the turbine, generator and electrical system. The power capture curve of the turbine has been simulated as well as the behaviour of a step response for a change in tip speed ratio. The simulated results agree well with experimental data except at low rotational speed where the accuracy of the calibration of the drag losses is reduced.

scholarly journals PARALLEL DISK CONTINUOUSLY VARIABLE TRANSMISSION (PDCVT):PROTOTYPE DEVELOPMENT AND PERFORMANCE TESTING

2014 ◽  
pp. 213-218
Author(s):  
PRASAD VINAYAK MARULKAR ◽  
S.G. JOSHI
Keyword(s):  
Weight Ratio ◽  
Performance Testing ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Rotating Disks ◽  
Parallel Disk ◽  
Prototype Development ◽  
Variable Transmission ◽  
The Coefficient Of Friction ◽  
And Performance

In this paper, a typical Parallel Disk Continuously Variable Transmission System (PDCVT) is developed in the spirit and approach of Kazerounian and Furu-Szekely. In situations where a speed ratio is required to be changed frequently, continuously variable transmission is one of the desirable solutions. The PDCVT system is one such solution which offers the advantages such as high power to weight ratio and reliability in operation. First of all, the development and manufacturing details of the developed PDCVT system are discussed and experimental and theoretical values of transmission ratios have been determined with different ball diameters and materials. Also, the theoretical and experimental evaluation of transmission torque has been carried out. Experiments have been carried out to determine the system parameters: the stiffness of the spring for preloading mechanism of the system and the area of contact between the balls and rotating disks to determine the coefficient of friction.

scholarly journals Performance Investigation of the Immersed Depth Effects on a Water Wheel Using Experimental and Numerical Analyses

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 982 ◽  
Author(s):  
Mengshang Zhao ◽  
Yuan Zheng ◽  
Chunxia Yang ◽  
Yuquan Zhang ◽  
Qinghong Tang
Keyword(s):  
Water Level ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Maximum Error ◽  
Radius Ratio ◽  
Maximum Efficiency ◽  
Water Volume ◽  
Speed Ratio ◽  
Water Wheel ◽  
Water Volume Fraction

The purpose of this research is to study the effect of different immersed depths on water wheel performance and flow characteristics using numerical simulations. The results indicate that the simulation methods are consistent with experiments with a maximum error less than 5%. Under the same rotational speeds, the efficiency is much higher and the fluctuation amplitude of the torque is much smaller as the immersed radius ratio increases, and until an immersed radius ratio of 82.76%, the wheel shows the best performance, achieving a maximum efficiency of 18.05% at a tip-speed ratio (TSR) of 0.1984. The average difference in water level increases as the immersed radius ratio increases until 82.76%. The water area is much wider and the water volume fraction shows more intense change at the inlet stage at a deep immersed depth. At an immersed radius ratio of 82.76%, some air intrudes into the water at the inlet stage, coupled with a dramatic change in the water volume fraction that would make the flow more complex. Furthermore, eddies are found to gradually generate in a single flow channel nearly at the same time, except for an immersed depth of 1.2 m. However, eddies generate in two flow channels and can develop initial vortexes earlier than other cases because of the elevation of the upstream water level at an immersed radius ratio of 82.76%.

Design of a Ducted Cross-Flow Turbine for Marine Current Energy Extraction

2018 ◽  
Author(s):  
Jai N. Goundar ◽  
Deepak D. Prasad ◽  
Mohammed Rafiuddin Ahmed
Keyword(s):  
Fossil Fuels ◽  
Fluid Dynamic ◽  
Cross Flow ◽  
Clean Energy ◽  
Experimental Results ◽  
Power Coefficient ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Marine Current ◽  
Current Energy

Marine current energy is a clean energy source and is a solution to the problems faced by burning fossil fuels such as global warming and climate change. Once tapped, the useful shaft power can be converted into electrical energy. To make this practical, the designed energy converter should be capable of operating at low marine current velocities, it should be suitable for installation at locations that have low water depths and should have lower manufacturing, installation and maintenance costs. A ducted cross-flow turbine has all the above features and it will be suitable for Pacific Island countries (PICs) for extracting marine current energy. The ducted cross-flow turbine was designed, modelled and analyzed in commercial Computational Fluid dynamic (CFD) code ANSYS-CFX. The inlet and outlet duct sizes were optimized for maximum output. Before the analysis of full model, the CFD results were validated with experimental results. Simulations for the 1:10 ducted cross-flow turbine (having a diameter of 150 mm) were performed with 400,000 nodes, as increase in the grid size did not make much difference other than increasing the simulation time significantly. The maximum difference in the power coefficient between CFD and experimental results was 6%. Simulations were then performed for the full-scale prototype, which has a duct (nozzle) inlet of 3.5 m × 3.5 m and a turbine diameter of 1.5 m, at three freestream velocities of 0.65 m/s, 1.95 m/s and 3.25 m/s. Analysis of the prototype performance showed that the ducted cross-flow turbine can reach a maximum efficiency of 56% and can produce 21.5 kW of power at a current speed of 1.95 m/s and 103.6 kW at 3.25 m/s. The designed cut-off speed was 4 m/s.

scholarly journals Modeling and performance calculation of a horizontal axis wind and hydrokinetic turbine: Numerical study

2018 ◽  
Vol 2 (2) ◽  
pp. 70-79
Author(s):  
Anastas Todorov Yangyozov ◽  
Damjanka Stojanova Dimitrova ◽  
Lazar Georgiev Panayotov
Keyword(s):  
Numerical Study ◽  
Numerical Calculations ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Ansys Cfx ◽  
Hydrokinetic Turbine ◽  
Wide Range ◽  
And Performance ◽  
Performance Calculation

A small turbine, working with air and water to generate electricity, was designed and its performance was reported in this paper. The rotor diameter is 150mm. The numerical calculations of the power coefficient, torque, and tip speed ratio of turbine were carried out for a wide range of inlet velocities. The flow passing through the turbine was investigated with commercial CFD code ANSYS CFX 18

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