Search

During a turbine's lifetime, minimizing the cost of power production should be the primary aim in addition to attaining high technical efficiency. Thus, this paper was aimed at enhancing the aerodynamic efficiency of a site-specific small wind turbine considering the cost of energy as one of the design parameters. The wind distribution of a specific site was employed to characterize the wind using the Weibull distribution method. The aerodynamics of a typical 5 kW wind turbine blade were investigated by implementing a blade element method (BEM) using a MATLAB code that applied the advancements and improvements with different modifications and which was validated by engaging computational fluid dynamics (Ansys-Fluent). The optimal pitch angle was then employed to further promote the performance characteristics of the blade. The cost of energy was reformulated in terms of rated power considering a cost variation of the main components that deviates with the rated power. Accordingly, the performance parameters were investigated against a varying rated power and the relative cost of energy, achieving a maximum power coefficient of 55.37% at a lower cost of energy. Moreover, annual energy production of approximately 18 MWh with a corresponding capacity factor of approximately 41% was achieved at a lower cost of energy. These findings demonstrate that the selected modelling, analysis procedures, and modifications enhance the aerodynamic performance characteristics and lower the cost of energy of the small wind turbine blade, which promotes the affordability and energy harnessing capability of small wind turbines. [ABSTRACT FROM AUTHOR]

This paper has presented the enhancement of tensile and impact strength of continuously aligned sisal fiber reinforced polyester composites through chemical treatment and hybridization. Sodium hydroxide (NaOH) and baking soda (NaHCO3) were used for sisal fiber treatment. Comparisons on the effect of sodium hydroxide and baking soda treatments on tensile and impact strength of the composites were performed. Unidirectional glass and carbon fibers were selected as hybrid fibers. Nineteen laminates were prepared as per the standards. The laminates were made of pure sisal fiber and hybridized with glass or carbon fibers at different stacking sequence, orientation, and volume fraction. The effects of glass and carbon fibers hybridization on tensile and impact strength of the composites were studied and compared. Further enhancements on the tensile and impact strength of the composites were investigated through alterations on the stacking sequence, orientation, and volume fraction of the hybrid fibers. Symmetric hybrid composites which avoided sisal/sisal plies interface have shown more than 95% and 130% rise in their tensile strength by adding about 8% volume of glass and carbon fibers respectively. Moreover, with only about 8% carbon fiber inclusion in the laminates, almost 60% improvements in the impact strength were discovered. [ABSTRACT FROM AUTHOR]

Mechanical and water-absorption properties of composites made from sisal fiber and polyester matrix have been investigated. Test specimens were prepared with untreated fiber and treated with alkaline solution of sodium hydroxide. The amount of fiber content in the composites varied with values of 10%, 20%, and 30% by volume. The test results indicate that the alkaline treatment has improved the tensile, compressive, and impact strength of the composite with the added benefit of low water absorption. The impact strength is found to increase with an increase in the fiber content. However, the tensile and compressive strengths have decreased; water-absorption rate has increased with an increase in the fiber content. [ABSTRACT FROM AUTHOR]