Numerical Predictions and Experimental Verifications for Hydrodynamic Performance of Tidal Stream Turbine

2013 ◽  
Vol 694-697 ◽  
pp. 630-634 ◽  
Author(s):  
Bin Guo ◽  
Da Zheng Wang ◽  
Jun Wei Zhou
Keyword(s):  
Water Channel ◽  
Hydrodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Circulating Water ◽  
Numerical Predictions ◽  
Ansys Cfx ◽  
Tidal Stream ◽  
Tidal Stream Turbine

Blade element momentum (BEM) theory is used to design the tidal stream turbine in this paper. ANSYS-CFX and numeca are used to predict the hydrodynamic performance of the turbine. The power coefficient of the turbine obtained by CFD is 39.36% at the design tip speed ratio. A 300mm diameter scale turbine has been built, and the tests were carried out in the circulating water channel, the power coefficient can reach 40.5% at the design tip speed ratio. Through the comparisons between experimental results and CFD results, it proves the application of the numerical method for blade design, and the distributions of the pressure and axial velocity near the blade are analyzed at the end of the paper.

Numerical Predictions and Verifications for Hydrodynamic Performance of Bidirectional Tidal Stream Turbine

2012 ◽  
Vol 229-231 ◽  
pp. 2478-2480
Author(s):  
Bin Guo ◽  
Da Zheng Wang ◽  
Jun Wei Zhou
Keyword(s):  
Hydrodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Numerical Predictions ◽  
Ansys Cfx ◽  
Tidal Stream ◽  
Cfd Method ◽  
Tidal Stream Turbine ◽  
Bem Theory ◽  
Blade Element

In this paper, the tidal stream turbine blade is designed by using blade element momentum (BEM) theory. The bidirectional airfoil is created derived from NACA airfoil. Ansys-CFX is used to predict the hydrodynamic performance of this bidirectional airfoil, and it turns out that the bidirectional airfoil works well at both of the tidal current directions. A test turbine named rotor 2 is used, and a comparison is made between experimental results of the test turbine and numerical prediction results to prove the correctness of the numerical method. The power coefficient of bidirectional tidal stream turbine obtained by CFD method is 39.36% at the design tip speed ratio.

6-DOF Numerical Simulation of the Vertical-Axis Water Turbine

2011 ◽  
Author(s):  
Xin Wang ◽  
Xianwu Luo ◽  
Baotang Zhuang ◽  
Weiping Yu ◽  
Hongyuan Xu
Keyword(s):  
Vertical Axis ◽  
Hydrodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Test Model ◽  
Tip Speed Ratio ◽  
Water Turbine ◽  
Tidal Stream ◽  
Static Head ◽  
Tidal Stream Turbine

Recent years, the vertical-axis water turbine (VAWT) is widely used for converting the kinetic energy of the moving water in open flow and with low static head like river and tidal sites. Conventional numerical methods such as disk-stream tube method and vortex panel method have some drawbacks to predict the behaviors and characteristics of the vertical-axis tidal stream turbine. This paper had treated the hydrodynamic performance of a VAWT model experimentally and numerically. Based on the present research, a 6-DOF method coupled with CFD suitable to simulate the rotor movement and predict the hydraulic performance for a VAWT was proposed. Compared with the experiments, the numerical results for the performance of the VAWT model were reasonable. It is also noted that there is a maximum power coefficient near tip speed ratio of 2.5 for the test model.

Vertical Axis Current Turbine (VACT) and its Efficiency

2013 ◽  
Author(s):  
Antonio Carlos Fernandes ◽  
Ali Bakhshandeh Rostami ◽  
Lucas Gomes Canzian ◽  
Sina Mirzaei Sefat
Keyword(s):  
Angular Velocity ◽  
Flat Plate ◽  
Water Channel ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Circulating Water ◽  
Property Changes ◽  
Current Turbine

This study examines the efficiency of a vertical axis current turbine (VACT) according to various non-dimensional mass moments of inertia. The vertical axis current turbine of drag force type with flat plate-shaped blade is tested. From experiments in a circulating water channel the angular velocity, the power coefficient and tip speed ratio of the vertical axis current turbine are obtained. The property changes for various conditions give the relationships between efficiency-related parameters. The maximum power coefficients of experiments occur at the tip speed ratio of approximately 0.35∼0.40. From the experiments, turbine is found to give a 7% power coefficient which related to I* = 0.52.

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

scholarly journals Study on Hydrodynamic Configuration Parameters of Vertical-Axis Tidal Turbine

2020 ◽  
Vol 27 (1) ◽  
pp. 116-125
Author(s):  
Li Guangnian ◽  
Qingren Chen ◽  
Yue Liu ◽  
Shanqiang Zhu ◽  
Qun Yu
Keyword(s):  
Vertical Axis ◽  
Hydrodynamic Performance ◽  
Numerical Code ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Variation Principle ◽  
Tip Speed Ratio ◽  
Tidal Turbines ◽  
Tidal Turbine ◽  
Vertical Axis Tidal Turbine

AbstractIn this paper, a numerical code for predicting the hydrodynamic performance of vertical-axis tidal turbine array is developed. The effect of the tip speed ratio, solidity, and preset angle on the hydrodynamic performance are discussed using a series of calculations. The load principle of the rotor and the variation principle of the turbine power coefficient are studied. All these results can be considered as a reference for the design of vertical-axis tidal turbines.

scholarly journals Performance assessment and optimization of a helical Savonius wind turbine by modifying the Bach’s section

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
M. Niyat Zadeh ◽  
M. Pourfallah ◽  
S. Safari Sabet ◽  
M. Gholinia ◽  
S. Mouloodi ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Performance Assessment ◽  
Turbulent Flows ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Basic Model ◽  
Turbine Performance ◽  
Primary Model ◽  
Savonius Wind Turbine

AbstractIn this paper, we attempted to measure the effect of Bach’s section, which presents a high-power coefficient in the standard Savonius model, on the performance of the helical Savonius wind turbine, by observing the parameters affecting turbine performance. Assessment methods based on the tip speed ratio, torque variation, flow field characterizations, and the power coefficient are performed. The present issue was stimulated using the turbulence model SST (k- ω) at 6, 8, and 10 m/s wind flow velocities via COMSOL software. Numerical simulation was validated employing previous articles. Outputs demonstrate that Bach-primary and Bach-developed wind turbine models have less flow separation at the spoke-end than the simple helical Savonius model, ultimately improving wind turbines’ total performance and reducing spoke-dynamic loads. Compared with the basic model, the Bach-developed model shows an 18.3% performance improvement in the maximum power coefficient. Bach’s primary model also offers a 12.4% increase in power production than the initial model’s best performance. Furthermore, the results indicate that changing the geometric parameters of the Bach model at high velocities (in turbulent flows) does not significantly affect improving performance.

Numerical Research on the Characteristics of Lift-Drag Type Vertical Axis Wind Turbine

2012 ◽  
Vol 189 ◽  
pp. 448-452
Author(s):  
Yan Jun Chen ◽  
Guo Qing Wu ◽  
Yang Cao ◽  
Dian Gui Huang ◽  
Qin Wang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Chord Length ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Middle Range ◽  
Parabolic Form ◽  
Cfd Method

Numerical studies are conducted to research the performance of a kind of lift-drag type vertical axis wind turbine (VAWT) affected by solidity with the CFD method. Moving mesh technique is used to construct the model. The Spalart-Allmaras one equation turbulent model and the implicit coupled algorithm based on pressure are selected to solve the transient equations. In this research, how the tip speed ratio and the solidity of blade affect the power coefficient (Cp) of the small H-VAWT is analyzed. The results indicate that Cp curves exhibit approximate parabolic form with its maximum in the middle range of tip speed ratio. The two-blade wind turbine has the lowest Cp while the three-blade one is more powerful and the four-blade one brings the highest power. With the certain number of blades, there is a best chord length, and too long or too short chord length may reduce the Cp.

scholarly journals Experimental Investigation of Helical Cross-Flow Axis Hydrokinetic Turbines, Including Effects of Waves and Turbulence

2011 ◽  
Author(s):  
Peter Bachant ◽  
Martin Wosnik
Keyword(s):  
Cross Flow ◽  
Surface Flow ◽  
Frame Rate ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Grid Turbulence ◽  
Flow Axis ◽  
Power Extraction ◽  
Tip Speed Ratio ◽  
Hydrokinetic Turbines

The performance characteristics of two cross-flow axis hydrokinetic turbines were evaluated in UNH’s tow and wave tank. A 1m diameter, 1.25m (nominal) height three-bladed Gorlov Helical Turbine (GHT) and a 1m diameter, four-bladed spherical-helical turbine (LST), both manufactured by Lucid Energy Technologies, LLP were tested at tow speeds up to 1.5 m/s. Relationships between tip speed ratio, solidity, power coefficient (Cp), kinetic exergy efficiency, and overall streamwise drag coefficient (Cd) are explored. As expected, the spherical-helical turbine is less effective at converting available kinetic energy in a relatively low blockage, free-surface flow. The GHT was then towed in waves to investigate the effects of a periodically unsteady inflow, and an increase in performance was observed along with an increase in minimum tip speed ratio at which power can be extracted. Regarding effects of turbulence, it was previously documented that an increase in free-stream homogenous isotropic turbulence increased static stall angles for airfoils. This phenomenon was first qualitatively investigated on a smaller scale with a NACA0012 hydrofoil in a UNH water tunnel, using an upstream grid turbulence generator and using high frame-rate PIV to measure the flow field. Since the angle of attack for a cross-flow axis turbine blade oscillates with higher amplitude as tip speed ratio decreases, any delay of stall should allow power extraction at lower tip speed ratios. This hypothesis was tested experimentally on a larger scale in the tow tank by creating grid turbulence upstream of the turbine. It is shown that the range of operable tip speed ratios is slightly expanded, with a possible improvement of power coefficient at lower tip speed ratios. Drag coefficients at higher tip speed ratios seem to increase more rapidly than in the non-turbulent case.

A Study on Water Pumping by Using a Small Multi-Blades Windmill for Used in a Remote Area

2013 ◽  
Vol 724-725 ◽  
pp. 527-530
Author(s):  
Yuttachai Keawsuntia
Keyword(s):  
Wind Velocity ◽  
Life Time ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Pump System ◽  
Tip Speed Ratio ◽  
Water Pumping ◽  
Overall Efficiency ◽  
Water Base ◽  
Rotor Model

The objective of this research is to study the small multi-blades windmill for water pumping by using a studying performance of windmill which has a curvature plate ratio of 0.07 and determine overall efficiency and evaluate economic of the system. The results from the test run of windmill rotor model in the wind tunnel at a wind velocity of 3 m/s, the windmill give maximum power coefficient of 0.296 at a tip speed ratio of 1.18. The results from the test run of the windmill-pump system at 2 m head have an overall efficiency of 0.239 at the wind velocity of 1.2 m/s. The output of 2.38 L/min, which implies a rate of return for water pumping at 0.038 USD per cubicmetre of water base on 10 year-life time of windmill.

Numerical Modeling of Vertical Axis Wind Turbines

2014 ◽  
Author(s):  
Teresa Parra-Santos ◽  
Armando Gallegos-Muñoz ◽  
Miguel A. Rodriguez-Beneite ◽  
Cristobal Uzarraga-Rodriguez ◽  
Francisco Castro-Ruiz
Keyword(s):  
Mechanical Energy ◽  
Vertical Axis ◽  
The Self ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Vertical Axis Wind Turbines ◽  
Selection Of ◽  
Rotor Axis

This paper aims to predict the performance of Vertical Axis Wind Turbine (VAWT), hence the modeling of kinetic energy extraction from wind and its conversion to mechanical energy at the rotor axis, is carried out. The H-type Darrieus turbine consists of three straight blades with shape of aerofoil attached to a rotating vertical shaft. The criterion on the selection of this kind of turbines, despite its reduced efficiency, is the easy manufacture in workshops. A parametric study has been carried out to analyze the camber effect on the non dimensional curves of power coefficient so that the self starting features as well as the range of tip speed ratio of operation could be predicted.

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