Computational Fluid Dynamics Investigation of a Novel Multiblade Wind Turbine in a Duct (original) (raw)
Related papers
Towards improving the aerodynamic performance of a ducted wind turbine: A numerical study
Journal of Physics: Conference Series, 2018
This paper aims to study the aerodynamic performance of ducted wind turbines (DWT) using inviscid and viscous flow calculations by accounting for the mutual interaction between the duct and the rotor. Two generalized duct cross section geometries are considered while the rotor is modelled as an actuator disc with constant thrust coefficient. The analysis shows the opportunity to significantly increase the overall aerodynamic performance of the DWT by a correct choice of the optimal rotor loading for a given duct geometry. Present results clearly indicate that the increased duct cross section camber leads to an improved performance for a DWT. Finally, some insights on the changes occurring to the performance coefficients are obtained through a detailed flow analysis.
3-D blade resolved CFD performance analysis of a Ducted Wind Turbine
14th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics
Ducted wind turbines are very promising wind energy concentrator-systems for smallscale applications exhibiting an appreciable power density increase compared with their open rotor competitors. The aim of this work is to build up a robust and automated methodology for the 3D blade-resolved performance analysis of these devices in view of their CFD-aided optimal design. The reliability of this procedure, based on an in-house Python module for the generation of the structured multi-block 3D mesh, is verified by comparing the obtained numerical results with available experimental data. The developed methodology is employed to spotlight the differences in terms of extracted power between open and ducted rotors and to investigate some typically-disregarded aspects playing a key role in the design and analysis of ducted wind turbines. Specifically, it is shown that the shrouding of an existing open rotor leads to a sub-optimal turbine operating condition as well as to a significantly change in the local features of the tip vortex and associated losses.
Effects of the duct thrust on the performance of ducted wind turbines
This work investigates the performance of ducted wind turbines (DWTs) through the axial momentum theory (AMT) as well as through a semi-analytical approach. Although the AMT points out that the duct thrust plays a key role in the enhancement of the power extraction, it does not allow for the evaluation of the flow field around the duct. For this reason, a semi-analytical model is also used to investigate the local and global features of the flow through a DWT. In comparison to the AMT, the proposed semi-analytical method can properly evaluate the performance of the device for each prescribed rotor load distribution and duct geometry. Moreover, in comparison to other linearised methods, this approach fully takes into account the wake rotation and divergence, and the mutual interaction between the turbine and the shroud. The analysis shows the opportunity to significantly increase the power output by enclosing the turbine in a duct and that the growth in the duct thrust has a beneficial effect onto the device performance. Finally, some insights on the changes occurring to the performance coefficients with the rotor thrust and the duct camber are obtained through a close inspection of the local features of the flow field.
Performance analysis of open and ducted wind turbines
In this paper the analysis of the aerodynamic performance of ducted wind turbines is carried out by means of a nonlinear and semi-analytical actuator disk model. It returns the exact solution in an implicit formulation as superposition of ring vortices properly arranged along the duct surface and the wake region. In comparison with similar and previously developed models, the method can deal with ducts of general shape, wake rotation and rotors characterised by radially varying load distributions. Moreover, the nonlinear mutual interaction between the duct and the turbine, and the divergence of the slipstream, which is particularly relevant for heavily loaded rotors, are naturally accounted for. Present results clearly show that a properly ducted wind turbine can swallow a higher mass flow rate than an open turbine with the same rotor load. Consequently, the ducted turbine achieves a higher value of the extracted power. The paper also presents a detailed comparison between the aforementioned nonlinear and semi-analytical actuator disk method and the widely diffused CFD actuator disk method. The latter is based on the introduction of an actuator disk model in a CFD package describing the effects of the rotor through radial profiles of blade forces distributed over a disk surface. A set of reference numerical data, providing the inviscid axisymmetric velocity and pressure field distributions, are generated with controlled accuracy. Owing to an in-depth analysis of the error generated by the semi-analytical method and to the exactness of the solution in its implicit form, the collected data are well-suited for code-to-code validation of existing or newly developed computational methods.
CFD Analysis of Torque and Power for Single Rotor, Dual Rotor, and Ducted Dual Rotor Wind Turbine
International Journal of Engineering and Advanced Technology, 2021
With the present advancement, a wind turbine needs a wind rotor with high torque and power. The present study aims to enhance the torque and power of wind turbine by employing the ducted dual rotor. In this regard, CFD analysis is performed to analyze the torque and power produced for horizontal axis single rotor bare wind turbine, dual rotor wind turbine, and convergent-divergent ducted type dual rotor wind turbine. The comparative study is conducted to enhance the power and torque for the aforementioned rotor type. The results highlight the maximum value of torque for a dual ducted wind turbine is 36.9% more than a dual rotor at 16 m/s of wind velocity and 92.2 % more than a single rotor at 16 m/s of wind velocity, and the maximum value of the power produced for a dual ducted wind turbine is 40.48% more than a dual rotor at 16 m/s of wind velocity and 139.66% more than a single rotor at 16 m/s of wind velocity. Therefore result suggested that a dual ducted wind turbine is better t...
A conceptual design of wind accelerating device is developed for small vertical axis wind turbine (VAWT) with the objective of improving incoming wind speed before reaching and subsequently hitting the turbine blades. Two design concepts which are round and square shape are modeled as a wind accelerating device. The working condition is similar to wind vane and venture effect principle. The performance of the device is analyzed using Computational Fluid Dynamic (CFD) method at various wind speed. The performance on wind speed after the device and power density is investigated. The results report that the device has successfully increased the wind flow speed. Besides that, the square shape design show better performance compare to round shape design in term of wind speed and power density.
Wind Turbine Blade Design with Computational Fluid Dynamics Analysis
2017
Although there are many blade profile have been improved for use in aviation and energy sector, there is still needed blade profiles which have higher performance especially the commercial horizontal axis wind turbine efficiency is taken into account. The purpose of this study is to obtain the new blade profiles which have higher lift (CL) and drag (CD) coefficients for wind turbine making geometric modifications on several NACA wing profile systematically. For this purpose, the performance of NACA and developed new profiles have been compared with each other using computational fluid dynamics analysis and it is seen that the new developed profiles have higher performance than NACA profiles. Later on, according to the Blade Element Momentum Theory (BEM Theory) turbine blades are designed with developed new profiles and 3-dimensional CFD analyses are performed. Increase in torque in the wind turbine is determined.
FLUID DYNAMICS SIMULATION OF A THREE– BLADED HORIZONTAL AXISWIND TURBINE
IAEME PUBLICATION, 2024
In this study, we present a comprehensive analysis utilizing Computational Fluid Dynamics (CFD) simulation techniques to investigate the aerodynamic performance of a three-bladed Horizontal Axis Wind Turbine (HAWT). The aim of this research is to gain insights into the complex flow phenomena and efficiency characteristics associated with the turbine's operation. With the increasing global demand for renewable energy sources, wind turbines have gained prominence as a sustainable solution for electricity generation. The aerodynamic efficiency of the turbine blades plays a crucial role in maximizing energy extraction from the wind flow. A detailed 3D geometry of the HAWT, including therotor blades, nacelle, and tower, is developed and meshed appropriately for an accurate representation of flow. Through systematic simulations, the velocity field, pressure distribution, and turbulence patterns around the wind turbine blades are visualized and analyzed. This study underscores the significance of employing CFD simulations as a valuable tool for evaluating wind turbine performance, thus paving the way for advancements in renewable energy technology through improved turbine design and enhanced energy output.
Coupling Numerical Methods and Analytical Models for Ducted Turbines to Evaluate Designs
Journal of Marine Science and Engineering
Hydrokinetic turbines extract energy from currents in oceans, rivers, and streams. Ducts can be used to accelerate the flow across the turbine to improve performance. The objective of this work is to couple an analytical model with a Reynolds averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) solver to evaluate designs. An analytical model is derived for ducted turbines. A steady-state moving reference frame solver is used to analyze both the freestream and ducted turbine. A sliding mesh solver is examined for the freestream turbine. An efficient duct is introduced to accelerate the flow at the turbine. Since the turbine is optimized for operation in the freestream and not within the duct, there is a decrease in efficiency due to duct-turbine interaction. Despite the decrease in efficiency, the power extracted by the turbine is increased. The analytical model under-predicts the flow rejection from the duct that is predicted by CFD since the CFD predicts separation but the analytical model does not. Once the mass flow rate is corrected, the model can be used as a design tool to evaluate how the turbine-duct pair reduces mass flow efficiency. To better understand this phenomenon, the turbine is also analyzed within a tube with the analytical model and CFD. The analytical model shows that the duct's mass flow efficiency reduces as a function of loading, showing that the system will be more efficient when lightly loaded. Using the conclusions of the analytical model, a more efficient ducted turbine system is designed. The turbine is pitched more heavily and the twist profile is adapted to the radial throat velocity profile.
The computational fluid dynamics performance analysis of horizontal axis wind turbine
International Journal of Power Electronics and Drive Systems (IJPEDS), 2019
Computational fluid dynamics (CFD) simulations were performed in the present study using ANSYS Fluent 18.0, a commercially available CFD package, to characterize the behaviour of the new HAWT. Static three-dimensional CFD simulations were conducted. The static torque characteristics of the turbine and the simplicity of design highlight its suitability for the GE 1.5xle turbine. The major factor for generating the power through the HAWT is the velocity of air and the position of the blade angle in the HAWT blade assembly. The paper presents the effect of The blade is 43.2 m length and starts with a cylindrical shape at the root then transitions to the airfoils S818, S825 and S826 for the root, body and tip respectively. This blade also has pitch to vary as a function of radius, giving it a twist and the pitch angle at the blade tip is 4 degrees. This blade was created to be similar in size to a GE 1.5xle turbine by Cornell University. In addition, note that to represent the blade being connected to a hub, the blade root is offset from the axis of rotation by 1 meter. The hub is not included in our model. The experimental analysis of GE 1.5xle turbine, so that possible the result of CFD analysis can be compared with theoretical calculations. CFD workbench of ANSYS is used to carry out the virtue simulation and testing. The software generated test results are validated through the experimental readings. Through this obtainable result will be in the means of maximum constant power generation from HAWT.