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.

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.

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.

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.

Numerical Investigation of an Optimised Horizontal Axis Tidal Stream Turbine

2019 ◽  
Author(s):  
Hassan El Sheshtawy ◽  
Ould el Moctar ◽  
Thomas E. Schellin ◽  
Satish Natarajan
Keyword(s):  
Output Power ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Navier Stokes Equations ◽  
Tidal Turbines ◽  
Tidal Turbine ◽  
Sst Turbulence Model ◽  
Tidal Stream ◽  
Tidal Stream Turbine

Abstract A tidal stream turbine was designed using one of the optimised hydrofoils, whose lift-to-drag ratio at an angle of attack of 5.2 degrees was 4.5% higher than that of the reference hydrofoil. The incompressible Reynolds-averaged Navier Stokes equations in steady state were solved using k-ω (SST) turbulence model for the reference and optimised tidal stream turbines. The discretisation errors and the effect of different y+ values on the solution were analysed. Thrust and power coefficients of the modelled reference turbine were validated against experimental measurements. Output power and thrust of the reference and the optimised tidal turbines were compared. For a tip speed ratio of 3.0, the output power of the optimised tidal turbine was 8.27% higher than that of the reference turbine of the same thrust.

scholarly journals Comparative Numerical Analysis on Vertical Wind Turbine Rotor Pattern of Bach and Benesh Type

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2311 ◽  
Author(s):  
Fanel Dorel Scheaua
Keyword(s):  
Numerical Analysis ◽  
Classical Model ◽  
3D Models ◽  
Turbine Rotor ◽  
Point Of View ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Ansys Cfx ◽  
Torque Coefficient ◽  
Bladed Rotor

In this work, 3D models in classic configuration of Bach and Benesh rotor type, as well as models with modified blade pattern geometry were analyzed from the air circulation point of view inside the rotor enclosure in order to identify the operating parameters differences according to rotor geometric modified configuration. Constructive design aspects are presented, as well as results obtained from the virtual model analysis in terms of circulation velocity and pressure values which enhance rotor operation related to torque and power coefficients. The rotors design pattern is made according to previous results obtained by different researchers who have performed numerical analysis on virtual models and tests on the experimental rotor models using the wind tunnel. The constructive solutions are describing two-bladed rotor models, in four new designed constructive variants and analyzed using ANSYS CFX. The air velocity specific values, static and total pressure recorded at the rotor blade level are highlighted, that influence the obtaining of rotor shaft torque and power. Also torque coefficient (CT) and power coefficient (CP) values according with specific values of tip speed ratio (TSR) are presented for each analyzed case. The analysis results show higher power coefficient values for analyzed Bach V2 and Benesh V2 rotor modified models compared to the classic Bach and Benesh models for 0.3 TSR of 0.11–012 CP, 0.4 TSR of 0.18 CP (Benesh V2 model) and 0.27 CP at 0.6 TSR (Bach V2). The resulted values confirm that Benesh V2 model offers higher CP up to 5% at TSR 0.3, 2% at TSR 0.6 and 3% at TSR 0.4 compared to the Benesh classical model. The Bach V2 model offers 4% higher CP compared to the classic Bach model at TSR 0.6. Based on these results it is intended the further analytical and experimental research in order to obtain optimal rotor pattern.

scholarly journals Numerical Model Analysis of Myring–Savonius wind turbines

2019 ◽  
Vol 4 (1) ◽  
pp. 180-185
Author(s):  
M. Saleh ◽  
Ferenc Szodrai
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Primary Objective ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Energy Potential ◽  
Cross Sectional ◽  
Tip Speed Ratio ◽  
Savonius Wind Turbine ◽  
Cfd Method

Nowadays the importance of renewable energy is growing, and the utilization of the low wind energy potential is getting crucial. There are turbines with low and high tip speed ratio. Turbines with low tip speed ratio such as the Savonius wind turbine can generate adequate amount of torque at low wind velocities. These types of turbines are also called drag machines. The geometry of the blade can greatly influence the efficiency of the device. With Computational Fluid Dynamics (CFD) method, several optimizations can be done before the production. In our paper the Savonius wind turbine blade geometry was based on the so-called Myring equation. The primary objective of this paper was to increase the power coefficient by modelling the effect of the wind on the turbine blade. For the sake of simplicity, a 2D cross-sectional area was investigated in the simulation with ANSYS CFX 19.1.

scholarly journals Performance evaluation of high-lift hydrofoils with a flap used in the design of horizontal-axis hydrokinetic turbines

2021 ◽  
Vol 19 ◽  
pp. 391-395
Author(s):  
A. Rubio-Clemente ◽  
◽  
J. Aguilar ◽  
E. Chica
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Cfd Simulation ◽  
Horizontal Axis ◽  
Hydrodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Three Dimensional Model ◽  
High Lift ◽  
Hydrokinetic Turbines

The hydrodynamic performance and the flow field of two horizontal-axis hydrokinetic turbines with and without a high-lift hydrofoil with a flap were investigated using computational fluid dynamics (CFD) simulation. For improving the accuracy of the numerical simulation, the user-defined function (UDF) of 6-degrees of freedom (6-DoF) was used in the Ansys Fluent software. Unsteady Reynolds-averaged Navier–Stokes (URANS) equations coupled to the SST 𝑘 − 𝜔 turbulence model were employed during the simulation. A three-dimensional model of both of the turbines with three blades was conducted for obtaining the performance curve of the power coefficient (𝐶𝑃) versus the tip speed ratio (TSR). The maximum power coefficients (𝐶𝑃𝑀𝑎𝑥) of the hydrokinetic turbines with and without a high-lift hydrofoil arrangement were 0.5050 and 0.419, respectively. Experimental data from the literature were used for the validation of the numerical results, specifically for the case when a rotor with traditional blades is utilized. In general, the simulation results were in good agreement with the experimental data.

Parametric Study of Crowned Blade in Horizontal Axial Turbine

2013 ◽  
Vol 732-733 ◽  
pp. 443-450
Author(s):  
Jun Wei Zhou ◽  
Da Zheng Wang
Keyword(s):  
Design Parameters ◽  
Speed Ratio ◽  
Tip Leakage Flow ◽  
Axial Turbine ◽  
Tip Speed Ratio ◽  
Turbine Efficiency ◽  
Tidal Stream ◽  
Blade Tip ◽  
Design Value ◽  
Cfd Method

The horizontal axial turbine could extract kinetic energy from both wind and tidal stream. In this paper, a type of horizontal axial turbine was designed with a crown stalled on the blade tip and the turbine was analyzed in a tidal stream. Several turbines with different geometries of the crowns were compared, whose power coefficients were numerically simulated by the CFD method. Effects of the crown design parameters, such as crown setting directions and different widths on turbine efficiency were discussed. Furthermore, when the turbine worked at different tip speed ratio, the results were discussed, either. By analysis of the results, it is could be concluded that a circular crown was sufficient to eliminate blade tip loss caused by tip leakage flow. The upstream semicircle crown modified the corresponding side foil pressure distribution to the design value, and so did the downstream semicircle crown. In the ellipse crowns testing, turbine efficiency was approximately in line with the value of crowns width. When the turbine with the circular crown worked at a little higher tip speed ratio than the design value, the crown was effective as before.

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