Effects of flow parameters on the performance of vertical axis swirling type Savonius wind turbine
30 Dec 2015-International Journal of Automotive and Mechanical Engineering (Universiti Malaysia Pahang)-Vol. 12, pp 2929-2943
TL;DR: In this paper, wind tunnel experiments were carried out on a geometrically optimal swirling Savonius turbine by varying flow parameters to determine their effects on power and torque coefficients.
Abstract: Wind tunnel experiments were carried out on a geometrically optimal swirling Savonius turbine by varying flow parameters to determine their effects on power and torque coefficients. The optimum geometrical configuration used in this experiment was adopted from an earlier study that features 0.20 blade overlap ratio, 195˚ blade arc angle, and 1.06 rotor aspect ratio of a 320 mm diameter rotor with closed top end plate. The parameters considered in this experimental are the hot air temperature, hot air mass flow rate, hot air inlet diameter of swirl chamber, and the free-stream wind velocity. The results indicate that higher hot air temperature and hot air mass flow rate promotes performance of the turbine while power coefficient reached maximum at a certain hot air inlet diameter. Tests on the optimum geometry at four wind velocities revealed that power coefficients are higher in higher wind velocities.
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TL;DR: In this article, a review of the optimization studies of Savonius turbine regarding its probable applications in harnessing hydrokinetic energy is presented, and the studies concerning each of the structural parameters influencing the turbine performance are discussed thoroughly.
31 citations
TL;DR: In this paper, the mean and turbulent flow parameters were investigated using a large eddy simulation for two models i.e. the actual urban area model and the wind tunnel scale (1:1000) model.
Abstract: Wind flow through urban areas is studied either by wind tunnel scale experiments or via computational fluid dynamics simulations through full-scale actual models. The large difference between the Reynolds numbers based on the geometries of actual cities and wind tunnel scale cities makes the dynamic similarity between the two models uncertain. In this study, the mean and turbulent flow parameters were investigated using a large eddy simulation for two models i.e. the actual urban area model and the wind tunnel scale (1:1000) model. Kuala Lumpur City Centre, Malaysia, was considered as the case study of an urban area. Vertical velocity profiles were plotted at five locations representing different building packing densities. The results of wind tunnel scale model largely agreed with the actual model with some discrepancies in the building vicinity and wakes. The dissimilarity of the wake patterns due to the large difference in Re was responsible for the deviations. Largest discrepancies were found in the lateral and wall-normal velocity components and turbulence stresses. The results casted a shadow on the applicability of the conclusions derived from the simulations on wind tunnel scale models to the actual urban environments they represented. The deviation between the two models should be assessed before proceeding with experimental or numerical simulations on small-sized models.
7 citations
TL;DR: In this article, the authors used glass fiber reinforced plastic (GFRP) to construct wind turbine blades and found the tensile strength of wind turbine blade as 3.790 N/cm2 for the calculation and 3.690 N/ cm2 for measurement.
4 citations
TL;DR: In this paper, the authors used large-eddy simulation through both the actual city model and a group of idealised models of different structures but the same average dimensions and building density as the actual urban areas.
Abstract: Many concerns related to natural ventilation in urban areas have been deduced from experimental or computational fluid dynamics simulations on idealised models. However, it is not definite that the flow through these idealised models presents similar characteristics to actual urban areas. The objective of this research is to suggest an approach to close the gap between idealised models and genuine cities; i.e., predict actual urban flow characteristics from the ready data of idealised models. The flow was simulated by large-eddy simulation through both the actual city model and a group of idealised models of different structures but the same average dimensions and buildingpacking-density as the actual city. The numerical setup was validated by comparison with wind tunnel measurements from the literature. It was found that an equivalent to the average velocity profile throughout an idealised model can be achieved by a mix of the “five-point spatial average” and the “four-point spatial average”. The vertical profiles of mean and turbulent windward velocities of the idealised models manifest a general similarity to those of the actual model. On the other hand, the cross-wind and wall-normal components show large discrepancies. In all cases, the idealised models exhibit very narrow atmospheric surface layer heights compared to the actual model. IM-RAN (which represents a structure of semi-random configuration) displayed the closest results to the actual model but condensed in half the actual model surface layer height. A correction formula was devised to close the gap between the two models. The results confirm the ability to utilise idealised models to deliver recommendations regarding urban environment planning; though, attention should be paid to the selection of the idealised model and corrections may be needed.
2 citations
Cites background from "Effects of flow parameters on the p..."
...Along with the persisting attempts to reduce the heat release from burning fossil fuels either by improving the efficiency of industrial equipment [1] or developing clean energy sources [2], scientific research targets planning modern cities of enhanced natural ventilation potentials and minimal solar absorption [3]....
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References
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TL;DR: In this paper, Monte Carlo techniques are used to fit dependent and independent variables least squares fit to a polynomial least-squares fit to an arbitrary function fitting composite peaks direct application of the maximum likelihood.
Abstract: Uncertainties in measurements probability distributions error analysis estimates of means and errors Monte Carlo techniques dependent and independent variables least-squares fit to a polynomial least-squares fit to an arbitrary function fitting composite peaks direct application of the maximum likelihood. Appendices: numerical methods matrices graphs and tables histograms and graphs computer routines in Pascal.
12,737 citations
TL;DR: Numerical methods matrices graphs and tables histograms and graphs computer routines in Pascal and Monte Carlo techniques dependent and independent variables least-squares fit to a polynomial least-square fit to an arbitrary function fitting composite peaks direct application of the maximum likelihood.
Abstract: Uncertainties in measurements probability distributions error analysis estimates of means and errors Monte Carlo techniques dependent and independent variables least-squares fit to a polynomial least-squares fit to an arbitrary function fitting composite peaks direct application of the maximum likelihood. Appendices: numerical methods matrices graphs and tables histograms and graphs computer routines in Pascal.
10,546 citations
"Effects of flow parameters on the p..." refers methods in this paper
...Then, the relative uncertainties of the dependent parameters were estimated based on the functional form of the independent parameters from the general uncertainty formula [26]....
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18 Dec 2009
TL;DR: In this article, a simplified HAWT rotor performance calculation procedure was proposed to evaluate the effect of drag and blade number on the optimum performance of wind turbine rotor performance, considering the Betz limit and the ideal horizontal axis wind turbine with wake rotation.
Abstract: Preface Acknowledgements Introduction: Modern wind energy and its origins Modern wind turbines History of wind energy Wind characteristics and resources Introduction General characteristics of the wind resource Characteristics of the atmospheric boundary layer Wind data analysis and resource estimation Wind turbine energy production estimates using statistical techniques Overview of available resource assessment data Wind measurements and instrumentation Advanced topics Aerodynamics of wind turbines General overview One-dimensional momentum theory and the Betz limit Ideal horizontal axis wind turbing with wake rotation' Airfoils and general concepts of aerodynamics Momentum theory and blade element theory Blade shape for ideal rotor without wake rotation General rotor blade shape performance prediction Blade shape for optimum rotor with wake rotation Generalized rotor design procedure Simplified HAWT rotor performance calculation procedure Effect of drag and blade number on optimum performance Advanced aerodynamic topics Mechanics and dynamics Wind turbine rotor dynamics Detailed and specialized dynamic models Electrical aspects of wind turbines Basic concepts of electric power Power transformers Electrical machines Power converters Ancillary electrical equipment Wind turbine design Design procedure Wind turbine topologies Materials Machine elements Wind turbine loads Wind turbine subsystems and components Design evaluation Power curve prediction Wind turbine loads Wind turbine subsystems and components Design evaluation Power curve prediction Wind turbine control Overview of wind turbine control systems Typical grid-connected turbine operation Supervisory control overview and implementation Dynamic control theory and implementation Wind turbine siting, system design and integration Wind turbine siting Installation and operation issues Wind farms Wind turbines and wind farms in electric grids Offshore wind farms Operation in severe climates Hybrid electrical systems Wind energy system economics Overview of economic assessment of wind energy systems Capital costs of wind energy systems Operation and maintenance costs Value of wind energy Economic analysis methods Wind energy market considerations Wind energy systems: environmental aspects and impacts Avian interaction with wind trubines Visual impact of wind turbines Wind turbine noise Electromagnetic interference effects Land-use environmental impacts Other environmental considerations Nomenclature Problems Index
2,354 citations
TL;DR: Manwell, Manwell, McGowan, and Rogers as discussed by the authors provide a thorough and highly accessible introduction to the cross-disciplinary field of wind energy engineering, including the theory, design, and application.
Abstract: WIND ENERGY EXPLAINED: THEORY, Design, and Application, by J.F. Manwell, J.G. McGowan, and A.L. Rogers, is intended to provide both a thorough and highly accessible introduction to the cross-disciplinary field of wind engineering. The economic viability and political appeal of wind power is on the increase, making this text a timely addition to the literature. It was developed to complement the increasing number of renewable/wind energy courses now available, it includes end-of-chapter tutorial sections, and it combines both academic and industrial experience. Its coverage spans every aspect of wind energy engineering
981 citations
"Effects of flow parameters on the p..." refers background in this paper
...Therefore, it can go beyond the limit of power coefficient (Cp) of purely drag-driven machines, which is 8% [14]....
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TL;DR: In this article, a Savonius rotor wind turbine was tested in the Vought Corporation Systems Division 4.9- x 6.1m Low Speed Wind Tunnel to determine aerodynamic performance.
Abstract: Fifteen configurations of a Savonius rotor wind turbine were tested in the Vought Corporation Systems Division 4.9- x 6.1-m Low Speed Wind Tunnel to determine aerodynamic performance. The range of values of the varied parameters was as follows: number of buckets, 2 and 3; nominal freestream velocity, 7 and 14 m/s; Reynolds number per meter, 4.32 x 10/sup 5/ and 8.67 x 10/sup 5/; rotor height, 1 and 1.5 m; rotor diameter (nominal), 1 m; bucket overlap, 0.0 to 0.1 m. The measured test variables were torque, rotational speed, and tunnel conditions. It is concluded that increasing Reynolds number and/or aspect ratio improves performance. The recommended configuration consists of two sets of two-bucket rotors, rotated 90 deg apart, with each rotor having a dimensionless gap width of 0.1 to 0.15.
381 citations
"Effects of flow parameters on the p..." refers background in this paper
...Among a number of VAWTs, the Savonius turbine is known as the most quiet wind power source as it runs at lowest tipspeed ratio [7]....
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