scholarly journals PENELITIAN KARAKTERISTIK AERODINAMIKA AEROFOIL SUDU SKEA NELAYAN NILA 80

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Sulistyo Atmadi

An economical electric-small-scale wind turbine is intended for an alternative source of energy for fishermans. For the power requirment of wind turbine with the wind condition in Indonesia, an aerofoil research is needed, in particular for the case of SKEA Nelayan Nila 80, with unknown aerofoil data. The focus of the research concentrated on finding aerodynamics characteristic Cl, Cd and Cm for angle of attack regime from 4 to 16 degrees. The result would be used in the modification of existing wind turbine. With limited engineering data, several integrated softwares had been used such as AutoCad 2004, Gambit and fluent 5.2.1 AutoCad was used to digitise aerofoil geometry, gambit was used for grid generation wich then fed into Fluent 5.2.1. for load analysis. The result was quite similiar to N-60 which gives stall angle at around 13 degree-15 degree and Cl per Cd maximum equal 16.

2019 ◽  
Vol 8 (4) ◽  
pp. 9557-9562

Wind energy is one of the most viable options for clean and sustainable energy production. In Malaysia where wind source has been considered scarce, the capacity of installed wind energy production is very low. However, studies have shown that it is worthwhile to produce wind energy at several potential sites in this country. For this purpose, it is crucial that the designed turbine blade gives the highest possible blade power efficiency while structure wise, the turbine blade need to be effective in terms of avoiding possible failures. The maximum power efficiency means the blade does not only provide profile that gives maximum sliding ratio but also it must operate at the corresponding angle of attack, 𝜶𝒎𝒂𝒙 that gives this ratio. At the same time, the blade must be small enough to have low weight to allow it to self-start in the low wind region. In this paper, the study is focused on the aerodynamic aspect of the design of wind turbine blade that will give the maximum power efficiency. Four factors that determine aerodynamic performance of the turbine blades are discussed: the wind condition, the airfoil profile, the blade geometry and the losses. In most of the factor, adjustments are made such that the blade operates at around the 𝜶𝒎𝒂𝒙 so that the sliding ratio and thus power coefficient are maximum.


2014 ◽  
Vol 624 ◽  
pp. 308-314
Author(s):  
Ming Xue Liu ◽  
Ye Fa Hu ◽  
Ru Hao Dong ◽  
Shi Min Peng ◽  
Hua Chun Wu

To effectively reduce friction torque and start-up wind speed, magnetic bearing was applied to the small-scale wind turbine. Load analysis is the primary task of the design for magnetic bearing in wind turbine. Based on a typical blade model, the aerodynamic performance of the impeller was simulated using Computational Fluid Dynamics (CFD) method. The characteristics and differences of the impeller’s aerodynamic performance under different wind speeds were analyzed and the aerodynamic loads were calculated as well. Moreover, the bearing capacity of magnetic bearing was calculated according to the forces on the spindle. A kind of permanent magnetic bearing (PMB) was designed for the radial supporting of the spindle in wind turbine. A prototype of the small-scale maglev wind turbine (SMWT) was presented, which provides some basis for the application of magnetic bearings in wind turbines.


2020 ◽  
Vol 17 (2) ◽  
pp. 833-839
Author(s):  
Muhamad Fadhli Ramlee ◽  
Ahmad Fazlizan ◽  
Sohif Mat

Among renewable energy resources, wind energy is one of the best alternative for power generation. Recently, vertical axis wind turbine (VAWT) received renewed interest as small-scale wind energy converter due to its suitability for urban application, where the wind condition is known to be unsteady and turbulence. Amongst various type of VAWTs, H-type Darrieus rotor has become more popular, thanks to its simple construction features, resulting to low manufacturing and installation cost. The aim of this paper is to evaluate numerically the power performance of straight-bladed Darrieus VAWT with different turbine solidity using computational fluid dynamic (CFD) technology. A series of two-dimensional CFD simulations of a three-bladed H-type Darrieus rotor were performed with 3 different solidities, σ (0.3, 0.5 and 0.7) to evaluate their power performance. Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations were used to calculate the instantaneous moment coefficient, Cm and power coefficient, Cp over a range of tip speed ratio, λ (0.5–4.5) with a free stream velocity of 8.0 m/s. The simulation results show that high solidity turbine performed well at low values of λ while turbine with low solidity has a wider operating range of λ and performed better at λ > 3.0 due to less blade-wake interactions between upstream and downstream halves of the turbine and lower blockage effect. The findings lend substantially to our understanding of physics flow around blades and turbine in order to optimize the power performance of small scale straight-bladed Darrieus VAWT operating in unsteady and turbulence wind condition.


Author(s):  
Salete Alves ◽  
Luiz Guilherme Vieira Meira de Souza ◽  
Edália Azevedo de Faria ◽  
Maria Thereza dos Santos Silva ◽  
Ranaildo Silva

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 592 ◽  
Author(s):  
Abraham M. Abraham ◽  
Reem M. Alnemari ◽  
Jana Brüßler ◽  
Cornelia M. Keck

Antioxidants are recommended to prevent and treat oxidative stress diseases. Plants are a balanced source of natural antioxidants, but the poor solubility of plant active molecules in aqueous media can be a problem for the formulation of pharmaceutical products. The potential of PlantCrystal technology is known to improve the extraction efficacy and antioxidant capacity (AOC) of different plants. However, it is not yet proved for plant waste. Black tea (BT) infusion is consumed worldwide and thus a huge amount of waste occurs as a result. Therefore, BT waste was recycled into PlantCrystals using small-scale bead milling. Their characteristics were compared with the bulk-materials and tea infusion, including particle size and antioxidant capacity (AOC) in-vitro. Waste PlantCrystals possessed a size of about 280 nm. Their AOC increased with decreasing size according to the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity) assays. The AOC of the waste increased about nine-fold upon nanonization, leading to a significantly higher AOC than the bulk-waste and showed no significant difference to the infusion and the used standard according to DPPH assay. Based on the results, it is confirmed that the PlantCrystal technology represents a natural, cost-effective plant-waste recycling method and presents an alternative source of antioxidant phenolic compounds.


2020 ◽  
Vol 37 ◽  
pp. 63-71
Author(s):  
Yui-Chuin Shiah ◽  
Chia Hsiang Chang ◽  
Yu-Jen Chen ◽  
Ankam Vinod Kumar Reddy

ABSTRACT Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3598
Author(s):  
Sara Russo ◽  
Pasquale Contestabile ◽  
Andrea Bardazzi ◽  
Elisa Leone ◽  
Gregorio Iglesias ◽  
...  

New large-scale laboratory data are presented on a physical model of a spar buoy wind turbine with angular motion of control surfaces implemented (pitch control). The peculiarity of this type of rotating blade represents an essential aspect when studying floating offshore wind structures. Experiments were designed specifically to compare different operational environmental conditions in terms of wave steepness and wind speed. Results discussed here were derived from an analysis of only a part of the whole dataset. Consistent with recent small-scale experiments, data clearly show that the waves contributed to most of the model motions and mooring loads. A significant nonlinear behavior for sway, roll and yaw has been detected, whereas an increase in the wave period makes the wind speed less influential for surge, heave and pitch. In general, as the steepness increases, the oscillations decrease. However, higher wind speed does not mean greater platform motions. Data also indicate a significant role of the blade rotation in the turbine thrust, nacelle dynamic forces and power in six degrees of freedom. Certain pairs of wind speed-wave steepness are particularly unfavorable, since the first harmonic of the rotor (coupled to the first wave harmonic) causes the thrust force to be larger than that in more energetic sea states. The experiments suggest that the inclusion of pitch-controlled, variable-speed blades in physical (and numerical) tests on such types of structures is crucial, highlighting the importance of pitch motion as an important design factor.


Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 622
Author(s):  
Yasser Elhenawy ◽  
Yasser Fouad ◽  
Haykel Marouani ◽  
Mohamed Bassyouni

This study aims to evaluate the effect of functionalized multi-walled carbon nanotubes (MWCNTs) on the performance of glass fiber (GF)-reinforced polypropylene (PP) for wind turbine blades. Support for theoretical blade movement of horizontal axis wind turbines (HAWTs), simulation, and analysis were performed with the Ansys computer package to gain insight into the durability of polypropylene-chopped E-glass for application in turbine blades under aerodynamic, gravitational, and centrifugal loads. Typically, polymer nanocomposites are used for small-scale wind turbine systems, such as for residential applications. Mechanical and physical properties of material composites including tensile and melt flow indices were determined. Surface morphology of polypropylene-chopped E-glass fiber and functionalized MWCNTs nanocomposites showed good distribution of dispersed phase. The effect of fiber loading on the mechanical properties of the PP nanocomposites was investigated in order to obtain the optimum composite composition and processing conditions for manufacturing wind turbine blades. The results show that adding MWCNTs to glass fiber-reinforced PP composites has a substantial influence on deflection reduction and adding them to chopped-polypropylene E-glass has a significant effect on reducing the bias estimated by finite element analysis.


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