scholarly journals Design and Optimization of a Multi-Element Hydrofoil for a Horizontal-Axis Hydrokinetic Turbine

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4679
Author(s):  
Jonathan Aguilar ◽  
Ainhoa Rubio-Clemente ◽  
Laura Velasquez ◽  
Edwin Chica
Keyword(s):  
Lift Coefficient ◽  
Electrical Energy ◽  
Chord Length ◽  
Horizontal Axis ◽  
Low Flow ◽  
Main Element ◽  
Water Current ◽  
Electric Generator ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine

Hydrokinetic turbines are devices that harness the power from moving water of rivers, canals, and artificial currents without the construction of a dam. The design optimization of the rotor is the most important stage to maximize the power production. The rotor is designed to convert the kinetic energy of the water current into mechanical rotation energy, which is subsequently converted into electrical energy by an electric generator. The rotor blades are critical components that have a large impact on the performance of the turbine. These elements are designed from traditional hydrodynamic profiles (hydrofoils), to directly interact with the water current. Operational effectiveness of the hydrokinetic turbines depends on their performance, which is measured by using the ratio between the lift coefficient (CL) and the drag coefficient (CD) of the selected hydrofoil. High lift forces at low flow rates are required in the design of the blades; therefore, the use of multi-element hydrofoils is commonly regarded as an adequate solution to achieve this goal. In this study, 2D CFD simulations and multi-objective optimization methodology based on surrogate modelling were conducted to design an appropriate multi-element hydrofoil to be used in a horizontal-axis hydrokinetic turbine. The Eppler 420 hydrofoil was utilized for the design of the multi-element hydrofoil composed of a main element and a flap. The multi-element design selected as the optimal one had a gap of 2.825% of the chord length (C1), an overlap of 8.52 %C1, a flap deflection angle (δ) of 19.765°, a flap chord length (C2) of 42.471 %C1, and an angle of attack (α) of –4°.

scholarly journals Design and hydrodynamic analysis of horizontal-axis hydrokinetic turbines with three different hydrofoils by CFD

2020 ◽  
Vol 18 (4) ◽  
pp. 529-536
Author(s):  
Betancur Diego ◽  
Ardila Gonzalo ◽  
Chica Lenin
Keyword(s):  
Social Impact ◽  
Numerical Study ◽  
Electrical Energy ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Hydrodynamic Analysis ◽  
Hydrokinetic Turbines ◽  
Shaft Power ◽  
Grid Convergence Index ◽  
Control Volumes

The conversion of kinetic energy that comes from low-head water currents to electrical energy has gained importance in recent years due to its low environmental and social impact. Horizontal axis hydrokinetic turbines are one of the most used devices for the conversion of this type of energy [1], being an emerging technology more studies are required to improve the understanding and functioning of these devices. In this context, the hydrodynamic study to obtain the characteristic curves of the turbines are fundamental. This article presents the design and hydrodynamic analysis for three horizontal axis tri-blade hydrokinetic turbine rotors with commercial profiles (NACA 4412, EPPLER E817 and NRELS802). The Blade Element Momentum (BEM) was used to design three rotors. The DesignModeler, Meshing and CFX modules from the ANSYS® commercial package were used to discretize the control volumes and configure the numerical study. In addition, Grid Convergence Index (GCI) analysis was performed to evaluate the precision of the results. The computational fluid dynamics (CFD) was used to observe the behavior of the fluid by varying the speed of rotation of the turbines from 0.1 rad s-1 to 40 rad s-1, obtaining power coefficient of 0.390 to 0.435. For a maximum shaft power of 105W. In addition, it is evident that for the same conditions the rotor designed with the EPPLER E817 profile presents better performance than built with the NACA4412 and NREL S802.

scholarly journals TRANSIENT MODELING OF A SMALL HYDROKINETIC TURBINE

2015 ◽  
Vol 14 (2) ◽  
pp. 63
Author(s):  
J. R. P. Vaz ◽  
T. H. S. Moreira ◽  
D. T. Brandão ◽  
J. J. A. Lopes ◽  
S. W. O. Figueiredo ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Clean Energy ◽  
Power Coefficient ◽  
Efficient Design ◽  
Electric Generator ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine ◽  
Mass Moment ◽  
Clean Energy Technology ◽  
Drive Train Model

In recent years, great attention has been given to the study of hydrokinetic turbines for power generation. Such importance is due to the use of clean energy technology by using renewable sources. Therefore, this work aims to present a relevant methodology for the efficient design of horizontal-axis hydrokinetic turbines with variable rotational speed. This methodology includes the Blade Element Method (BEM) for determining the turbine power coefficient, since BEM is widely used in the hydrokinetic turbine design due to its good agreement with experimental data. In addition, the dynamic equation of the driveline is used, taking into account the BEM to provide the rotor hydrodynamic torque coupled with the drive train model, including the multiplier and the electric generator. In this case, the modeling of the whole system comprises the hydrodynamic information of the rotor, the mass-moment of inertia, frictional losses and electromagnetic torque imposed by the generator. The theoretical results were obtained for the transient rotational speed and compared with field data measured from small hydrokinetic turbine installed at the Arapiranga-Açu creek, which is located in the city of Acará, Pará, Brazil.

Passive Pitch Control of Horizontal Axis Marine Hydrokinetic Turbine Blades

2014 ◽  
Author(s):  
Michael R. Motley ◽  
Ramona B. Barber
Keyword(s):  
Alternative Energy ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Pitch Control ◽  
Fluid Forces ◽  
Hydrokinetic Turbines ◽  
Energy Technologies ◽  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic

As the need for clean and renewable energy becomes greater, alternative energy technologies are becoming more and more prevalent. To that end, there has been a recent increase in research on marine hydrokinetic turbines to assess their potential as a reliable source of energy production and to expedite their implementation. These turbines are typically constructed from fiber reinforced composites and are subject to large, dynamic fluid forces. One of the benefits of composite materials is that the bend-twist deformation behavior can be hydroelastically tailored such that the blades are able to passively change their pitch to adapt to the surrounding flow, creating a nearly instantaneous control mechanism that can improve system performance over the expected range of operating conditions. These improvements include increasing energy capture, reducing instabilities, and improving structural performance. Practical constraints, however, lead to limitations in the scope of these performance enhancements and create tradeoffs between various benefits that can be achieved. This paper presents a numerical investigation into the capability of passive pitch control and combined active/passive pitch control to modify the performance of horizontal axis marine turbines with proper consideration of practical restrictions.

scholarly journals Marine current energy assessment and the hydrodynamic design of the hydrokinetic turbine for the Moroccan Mediterranean Coast

2021 ◽  
pp. 014459872098662
Author(s):  
Salma Hazim ◽  
Abdelouahab Salih ◽  
Mourad Taha Janan ◽  
Ahmed El Ouatouati ◽  
Abdellatif Ghennioui
Keyword(s):  
Electrical Energy ◽  
Mediterranean Coast ◽  
Electricity Production ◽  
Blade Element Theory ◽  
Hydrokinetic Turbine ◽  
Marine Current ◽  
Current Resource ◽  
Suitable Area ◽  
The Impact ◽  
Current Energy

Generating electricity through renewable energies is growing increasingly to reduce the huge demand on electricity and the impact of fossil energies on the environment, the most common sources forms used are: the wind, the sun, the photovoltaic and the thermal, without forgetting hydropower by the bays of dams. Fortunately, 70% of our planet is covered by the seas and oceans, this area constitutes a huge potential for electricity production to be exploited. The scientific advances of recent years allow a better exploitation of these resources especially the marine current due to its reliability and predictability. The marine current energy is extracted using a hydrokinetic turbine (HKT) which transform the kinetic energy of water into an electrical energy. The exploitation of this resource needs in the first step the assessment of marine currents in the study area for implementing the HKT, and the second step is designing an adequate technology. The main goal of this study is the assessment of the marine current resource on the Moroccan Mediterranean coast to evaluate the suitable area to implement the HKT, and to determine the marine current speed intensities at different depths. As well as, to estimate an average potential existing in the site. Moreover, we will conduct a study based on the results of the assessment that was made to design a horizontal axis marine current turbine (HAMCT). Two hydrofoil profile were considered to design a HAMCT using the Blade Element Theory (BEM) and calculating their performances adapted to the site conditions Naca4415 and s8052. In addition, a comparison was made between this two HAMCT hydrofoil profile for deciding the best one for implementing in the studied area.

scholarly journals Numerical investigation of stall characteristics for winglet blade of a horizontal axis wind turbine

2021 ◽  
Vol 321 ◽  
pp. 03004
Author(s):  
Shalini Verma ◽  
Akshoy Ranjan Paul ◽  
Anuj Jain ◽  
Firoz Alam
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Numerical Investigation ◽  
Turbulence Intensity ◽  
Geometric Modeling ◽  
Cfd Simulation ◽  
Lift Coefficient ◽  
Horizontal Axis ◽  
Renewable Energy Resources ◽  
Horizontal Axis Wind Turbine

Wind energy is one of the renewable energy resources which is clean and sustainable energy and the wind turbine is used for harnessing energy from the wind. The blades are the key components of a wind turbine to convert wind energy into rotational energy. Recently, wingtip devices are used in the blades of horizontal axis wind turbine (HAWT), which decreases the vortex and drag, while increases the lift and thereby improve the performance of the turbine. In the present study, a winglet is used at the tip of an NREL phase VI wind turbine blade. Solidworks, Pointwise, and Ansys-Fluent are used for geometric modeling, computational grid generation, and CFD simulation, respectively. The computational result obtained using SST k-ω turbulence modeling is well validated with the experimental data of NREL at 5 and 7 m/s of wind speeds. Numerical investigation of stall characteristics is carried out for wingleted blade at higher turbulence intensity (21% and 25%) and angle of attack (00 to 300 at 50 intervals) at 7 m/s wind speed. The result found that wingletd blade delay stall to 150 for both the cases of turbulence intensity. Increasing the turbulence intensity increases the lift coefficient at stall angle but drag coefficient also increases and thus a lower aerodynamic performance (CL/CD ratio = 13) is obtained. Wingleted blade improves the performance as the intensity of vortices is smaller compared to baseline blade

scholarly journals Numerical Simulation of the Anti-Icing Performance of Electric Heaters for Icing on the NACA 0012 Airfoil

Aerospace ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 123
Author(s):  
Sho Uranai ◽  
Koji Fukudome ◽  
Hiroya Mamori ◽  
Naoya Fukushima ◽  
Makoto Yamamoto
Keyword(s):  
Numerical Simulation ◽  
Lift Coefficient ◽  
Heating Surface ◽  
Leading Edge ◽  
Simulation Method ◽  
Chord Length ◽  
Ice Accretion ◽  
Suction Surface ◽  
Edge Surface ◽  
Naca 0012

Ice accretion is a phenomenon whereby super-cooled water droplets impinge and accrete on wall surfaces. It is well known that the icing may cause severe accidents via the deformation of airfoil shape and the shedding of the growing adhered ice. To prevent ice accretion, electro-thermal heaters have recently been implemented as a de- and anti-icing device for aircraft wings. In this study, an icing simulation method for a two-dimensional airfoil with a heating surface was developed by modifying the extended Messinger model. The main modification is the computation of heat transfer from the airfoil wall and the run-back water temperature achieved by the heater. A numerical simulation is conducted based on an Euler–Lagrange method: a flow field around the airfoil is computed by an Eulerian method and droplet trajectories are computed by a Lagrangian method. The wall temperature distribution was validated by experiment. The results of the numerical and practical experiments were in reasonable agreement. The ice shape and aerodynamic performance of a NACA 0012 airfoil with a heater on the leading-edge surface were computed. The heating area changed from 1% to 10% of the chord length with a four-degree angle of attack. The simulation results reveal that the lift coefficient varies significantly with the heating area: when the heating area was 1.0% of the chord length, the lift coefficient was improved by up to 15%, owing to the flow separation instigated by the ice edge; increasing the heating area, the lift coefficient deteriorated, because the suction peak on the suction surface was attenuated by the ice formed. When the heating area exceeded 4.0% of the chord length, the lift coefficient recovered by up to 4%, because the large ice near the heater vanished. In contrast, the drag coefficient gradually decreased as the heating area increased. The present simulation method using the modified extended Messinger model is more suitable for de-icing simulations of both rime and glaze ice conditions, because it reproduces the thin ice layer formed behind the heater due to the runback phenomenon.

scholarly journals Potential of the Lower Daugava for Siting Hydrokinetic Turbines / Daugavas Lejteces Enerģētiskais Potenciāls Hidrokinētisko Turbīnu Izmantošanai

2013 ◽  
Vol 50 (2) ◽  
pp. 3-14 ◽  
Author(s):  
A. Kalnach ◽  
J. Kalnach ◽  
A. Mutule ◽  
U. Persis
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Electricity Generation ◽  
Flow Characteristics ◽  
Water Density ◽  
Energy Potential ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine

The article outlines the requirements and criteria for the hydrokinetic turbine site and determines the water flow characteristics based on which the energy potential of such a turbine is calculated for lower reaches of the River Daugava. The changes in the energy potential caused by fluctuations in the water density and flow rate are evaluated. Two investigated spans (total > 22 km) are split into ten smaller subregions with similar characteristics and comparatively evaluated regarding their suitability for electricity generation by hydrokinetic turbines.

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