In this study,the performance of a contra rotating vertical-axis tidal-current turbine was investigated.The incompressible unsteady Reynolds-averagedNavier-Stokes(U-RANS)equations were solved via two-dimensional(2D)nu...In this study,the performance of a contra rotating vertical-axis tidal-current turbine was investigated.The incompressible unsteady Reynolds-averagedNavier-Stokes(U-RANS)equations were solved via two-dimensional(2D)numerical simulation using ANSYS Fluent computational fluid dynamics(CFD)code.An algorithm known as SIMPLE from the CFD code was used to calculate the pressure-velocity coupling and second-order finite-volume discretization for all the transport equations.The base turbine model was validated using the available experimental data.Three given scenarios for the contra rotating turbine were modeled.The contra rotating turbine performs better in a low tip speed ratio(TSR)than in a high TSR operation.In a high TSR operation,the contra rotating turbine inefficiently operates,surviving to rotate in the chaotic flow distribution.Thus,it is recommended to use contra rotating turbine as a part of new design to increase the performance of a vertical-axis tidal-current turbine with a lower TSR.展开更多
The instantaneous angle of attack on the blade has a significant effect on the hydrodynamic performance of a vertical-axis tidal-current turbine with straight blades. This paper investigates the influence of different...The instantaneous angle of attack on the blade has a significant effect on the hydrodynamic performance of a vertical-axis tidal-current turbine with straight blades. This paper investigates the influence of different preset angles of attack on the hydrodynamic performance of a three-bladed, vertical-axis, tidal-current turbine both experimentally and numerically. Experiments are carried out in a towing tank. This tested turbine＇s solidity is 0.1146. The preset angles of attack on the blade are -3°, 0°, 3°, and 5°, in the experiments. Experimental results show that with the increase of the preset angle of attack from -3°, to 5°, the hydrodynamic performance of the turbine is improved significantly with the power coefficients being increased from 15.3% to 34.8%, respectively. Compared to the result of a 0° preset angle of attack, the performance of the turbine with positive preset angles of attack is experimentally demonstrated to be beneficial. This performance improvement is also shown by numerical simulations based on the Unsteady Reynolds Averaged Navier-Stokes （URANS） equations. In addition, the numerical results show that the optimal positive preset angle of attack is 7° for the turbine studied. The corresponding power coefficient is 38%. Beyond this optimal preset angle of attack, the hydrodynamic performance of the turbine decreases. Therefore, due to the dynamic stall phenomenon, an optimal preset angle of attack exists for any vertical-axis turbine. This value should be considered in the design of a vertical-axis tidal-current turbine. words：展开更多
为解决海上风力发电不稳定的问题,并为借助海上风电的带动效应推动潮流能发电从示范应用阶段迈向产业化发展新阶段,本文基于地理信息系统(Geographic information system,GIS)、改进的多准则决策(Multi-criteria decision-making,MCDM)...为解决海上风力发电不稳定的问题,并为借助海上风电的带动效应推动潮流能发电从示范应用阶段迈向产业化发展新阶段,本文基于地理信息系统(Geographic information system,GIS)、改进的多准则决策(Multi-criteria decision-making,MCDM)方法,提出并构建了风-流联合开发区划框架。该框架包括可开发区域确定和开发适宜性评价两阶段,并设立排除指标集和评价指标集。为降低决策过程中的主观偏差,同时充分发挥多领域专家评价的优势,本文提出群体模糊层次分析(Group fuzzy analytic hierarchy process,GFAHP)法,并用来计算指标权重。此外,综合考虑方案相对接近度和属性值的变化态势,本文利用灰色接近理想点(Grey relation analysis-technique for order preference by similarity to an ideal solution,GRA-TOPSIS)法来计算适宜性指数。最后,将此决策框架应用于山东省海域,旨在为山东省风-流联合开发提供参考依据。展开更多
基金funded by the Directorate General of Resources for Science,Technology and Higher Education,Ministry of Research,TechnologyHigher Education of Republic Indonesia under a scheme called The Education of Master DegreeLeading to Doctoral Program for Excellent Graduates(PMDSU)undercontract number 135/SP2H/LT/DRPM/IV/2017
文摘In this study,the performance of a contra rotating vertical-axis tidal-current turbine was investigated.The incompressible unsteady Reynolds-averagedNavier-Stokes(U-RANS)equations were solved via two-dimensional(2D)numerical simulation using ANSYS Fluent computational fluid dynamics(CFD)code.An algorithm known as SIMPLE from the CFD code was used to calculate the pressure-velocity coupling and second-order finite-volume discretization for all the transport equations.The base turbine model was validated using the available experimental data.Three given scenarios for the contra rotating turbine were modeled.The contra rotating turbine performs better in a low tip speed ratio(TSR)than in a high TSR operation.In a high TSR operation,the contra rotating turbine inefficiently operates,surviving to rotate in the chaotic flow distribution.Thus,it is recommended to use contra rotating turbine as a part of new design to increase the performance of a vertical-axis tidal-current turbine with a lower TSR.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.DUT13JN10)the Doctoral Starting Up Funds of Liaoning Province(Grant No.20111029)
文摘The instantaneous angle of attack on the blade has a significant effect on the hydrodynamic performance of a vertical-axis tidal-current turbine with straight blades. This paper investigates the influence of different preset angles of attack on the hydrodynamic performance of a three-bladed, vertical-axis, tidal-current turbine both experimentally and numerically. Experiments are carried out in a towing tank. This tested turbine＇s solidity is 0.1146. The preset angles of attack on the blade are -3°, 0°, 3°, and 5°, in the experiments. Experimental results show that with the increase of the preset angle of attack from -3°, to 5°, the hydrodynamic performance of the turbine is improved significantly with the power coefficients being increased from 15.3% to 34.8%, respectively. Compared to the result of a 0° preset angle of attack, the performance of the turbine with positive preset angles of attack is experimentally demonstrated to be beneficial. This performance improvement is also shown by numerical simulations based on the Unsteady Reynolds Averaged Navier-Stokes （URANS） equations. In addition, the numerical results show that the optimal positive preset angle of attack is 7° for the turbine studied. The corresponding power coefficient is 38%. Beyond this optimal preset angle of attack, the hydrodynamic performance of the turbine decreases. Therefore, due to the dynamic stall phenomenon, an optimal preset angle of attack exists for any vertical-axis turbine. This value should be considered in the design of a vertical-axis tidal-current turbine. words：
文摘为解决海上风力发电不稳定的问题,并为借助海上风电的带动效应推动潮流能发电从示范应用阶段迈向产业化发展新阶段,本文基于地理信息系统(Geographic information system,GIS)、改进的多准则决策(Multi-criteria decision-making,MCDM)方法,提出并构建了风-流联合开发区划框架。该框架包括可开发区域确定和开发适宜性评价两阶段,并设立排除指标集和评价指标集。为降低决策过程中的主观偏差,同时充分发挥多领域专家评价的优势,本文提出群体模糊层次分析(Group fuzzy analytic hierarchy process,GFAHP)法,并用来计算指标权重。此外,综合考虑方案相对接近度和属性值的变化态势,本文利用灰色接近理想点(Grey relation analysis-technique for order preference by similarity to an ideal solution,GRA-TOPSIS)法来计算适宜性指数。最后,将此决策框架应用于山东省海域,旨在为山东省风-流联合开发提供参考依据。
