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In this study, the meteorological statistics recorded of seven-year wind speed data of the capital city of Jordan, Amman at height 10 m is utilized to assess the potential of wind energy. Also, statistical assessment of wind characteristics is evaluated by the two-parameter Weibull function. Monthly and annual wind speed variation is also analyzed. The study shows that Amman city is more suitable for small-scale wind turbine farms with the current wind speeds. The values of the shape Parameter K, and scale Parameter c show a various ranges between (1-1.5) and (1.5 m/s-3.5 m/s), respectively. It was also noticed that the annual mean wind speed v̅ is between 2.2 and 3.02 m/s. Results also showed that the highest wind power density is in June whereas the lowest is in October. In wind direction estimation, it was found that most of wind direction for the seven-years is between the southwest and the northwest, i.e. (135°-215°).

No abstract

The Savonius wind turbine is considered as one of the best vertical axis wind turbines for harvesting the kinetic energy from the wind in the urban areas, due to magnificent features such as high starting torque, low construction and maintenance costs, simple design, and self-starting ability especially at low wind speed. However, the conventional style of the Savonius rotor suffers from low efficiency. Consequently, modifying the configuration of the rotor may be an appropriate solution for providing electricity to the communities with no access to the power grid. Thus, this study aims to enhance the performance of the conventional Savonius rotor with an external overlap by adding an inner blade to the rotor configuration. Hence, a comparison study between five new arrangements against the conventional rotor in terms of power coefficient (Cp) and torque coefficient (Ct) is performed through a two-dimensional simulation by using ANSYS Fluent 19.2. The k-ε/Realizable turbulence model is employed in the simulation. Results conclude that inner blade with an angle of 120° increases the power coefficient by 41%, 39%, and 7% at tip speed ratio (TSR) = 0.7, 0.6, and 0.5, respectively.

The Savonius wind turbine is considered as one of the solutions for harvesting the kinetic energy from the wind in the urban areas, due to magnificent features such as, low construction cost, high starting torque, and self-starting ability especially at low wind speed. However, the conventional rotor suffers from low efficiency. Thus, modifying the configuration of the rotor may be an effective solution for providing electricity to the communities with no access to the power grid. Thus, this investigation aims to study numerically the effect of adding two inner blades on the performance of the Savonius wind rotor at low tip speed ratios (TSRs). The simulations are carried out using the two-dimensional simulation with the assist of ANSYS software. For turbulence modelling, the K-ε/realizable model was adopted in this study. Power coefficient (C p ) and torque coefficient (C t ) at various TSRs for the rotor are determined under a constant external overlap of 0.018 m. Furthermore, the effect of space between the inner blades was also investigated using three values of spacing. The simulation results show that the rotor with two inner blades performs better than the same rotor without inner blades at all tested TSRs expect at low considered values of 0.2 and 0.25. The heights Cp was 0.188 with 17.1% performance improvement at TSR = 0.4. Furthermore, the numerical results show that C p values decrease with the decrease of the space between the blades.

No abstract

Wind power is one of the green energies that could be used for meeting these energy demands. This is attributed to the fact that such a source of power is free and widely available. Savonius wind rotor can work at low wind speeds which fits well the rural areas. Despite its cheap, robust, and simple design, the Savonius rotor has some negatives such as relatively low efficiency and high fluctuations of static torque. Given this, the main goal of this research is to improve the output power of the Savonius wind rotor by varying the blade thickness using numerical simulation. Investigation methods based on the rotational speed of the rotor tip, wind field characterizations, torque, and power coefficients are conducted. The K-Ɛ/realizable model was utilized for simulating the rotor at 9 m/s wind speed via Ansys Fluent software. Results demonstrate that the newlydeveloped rotor with varying blade thickness has a less wind wake on the internal surface of the returning blade. Moreover, the suction vortices have a higher velocity for the new configuration causing a reduction in pressure on the outer side of the returning rotor which indicates less negative torque. Compared with the traditional Savonius blades, the new model shows a 40% performance enhancement in the maximum power coefficient. The maximum power coefficient is found to be 0.20. This configuration can be useful for small-scale electricity generation in urban areas.

The performance of the single and double blade Savonius rotors are numerically analyzed using the K-ε/realizable turbulence model. The computations are implemented at different values of tipspeed ratio from 0.2 to 0.4 with a step of 0.05. Both rotors have the same dimensions with an external overlap between their blades equals 0.02 m. The results indicate that the double blade rotor performs better than the single blade rotor in terms of power coefficient. In addition, the torque coefficient is improved at all tested values of tip-speed ratio. Furthermore, the results of the simulation show that the maximum power coefficient was 0.163 at tip-speed ratio = 0.4 for the double blade rotor, whereas the maximum improvement of the double blade rotor occurs at tipspeed ratio = 0.2 with a percentage of 11.86% compared to the single blade rotor. Moreover, the highest value of the torque coefficient was 0.524 at tip-speed ratio = 0.2 for the double blade rotor.