Genetic Algorithm Based Optimization Technique for Savonius-Style Wind Turbine

2021 ◽  
Author(s):  
Diplina Paul ◽  
Abhisek Banerjee
Keyword(s):  
Numerical Simulation ◽  
Genetic Algorithm ◽  
Flow Field ◽  
Wind Turbine ◽  
Fitness Function ◽  
Optimization Technique ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Speed Ratio ◽  
Two Dimensional

Abstract In this article, authors have studied genetic algorithm-based optimization technique to optimize rotor profile for elliptic shaped Savonius-style wind turbine with an aim to maximize the coefficient of performance. Genetic algorithm has been used to optimize design variables having distinct values and discontinuous and nondifferentiable objective functions. Optimization procedure using genetic algorithm uses the following steps: initialization, assessment, assortment, crossover and lastly alteration. Once the genetic algorithm is initialized, then the evaluation process trails, where each parametric value is evaluated based on the fitness function stated as objective function. Then the GA operators i.e assortment, cross over and alteration are applied. At the end of GA operation procedure, a new set of values of design parameter is generated. This procedure is endlessly iterated until the convergence criteria is met. Then the optimized and non-optimized profiles are studied using numerical simulation. Initially a two-dimensional numerical model is developed and validated against experimental results. The two-dimensional analysis is conducted using k-ω shear stress transport model. Unsteady Reynold’s Averaged Navier Stoke’s equations have been solved to simulate the flow field of a Savonius-style rotor. This analysis has been executed using finite volume approach in Fluent 17.2 version. Grid independence study is performed to curtail the effect of grid size on the flow field portrayals. The optimization technique implemented on the Savonius-style wind turbine, generated design parameters that were able to yield a coefficient of performance value of 0.398. The coefficient of torque and coefficient of performance values are studied for both optimized and non-optimized profile as a function of tip speed ratio. Numerical simulation predicted a maximum gain of 41% for coefficient of performance at TSR = 1.0 over for optimized profile over the non-optimized profile.

scholarly journals Optimization of Biofilter Size for Aquaponics Using Genetic Algorithm

2021 ◽  
Vol 25 (5) ◽  
pp. 632-638
Author(s):  
Amir A. Bracino ◽  
Jason L. Española ◽  
Argel A. Bandala ◽  
Elmer P. Dadios ◽  
Edwin Sybingco ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Loading Rate ◽  
Fitness Function ◽  
Optimization Technique ◽  
Water Flow Rate ◽  
Nitrifying Bacteria ◽  
Design Parameters ◽  
Heuristic Solution ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading

Unlike a media-filled aquaponic system, the nutrient film technique (NFT) and deep water culture (DWC) require the installation of an external biofilter to provide sufficient area for nitrifying bacteria colonization, which is essential for the conversion of toxic ammonia from fish waste into nitrate that is easily assimilated by plants. Given the importance of biofilters, it is imperative to properly design this tank to effectively support the nitrification process. Several factors need to be considered for the biofilter design. Thus, an optimization algorithm can be used to obtain combinations of the design parameters. The genetic algorithm (GA) is a heuristic solution search or optimization technique based on the Darwinian principle of genetic selection. The main goal of this study was to obtain the optimal biofilter size for a given fishpond volume and the amount of ammonia to be treated. The conversion coefficient in the Michaelis–Menten equation was used as the fitness function in this study. The parameters optimized using GA include the hydraulic loading rate, height of the biofilter, and predicted ammonia concentration. For the given assumption of a 60 kg feed introduced to the system and a 1500 L fishpond, the hydraulic loading rate, biofilter height, and final concentration of ammonia were 0.17437 m, 0.58585 m, and 0.01026 ppm, respectively. Using the values obtained from running the GA, the optimum biofilter volume for the system was 0.4608 m3, whereas the water flow rate was 0.03 L/min. For recommendations, multiple objective GAs can be used to add cost-related variables in the optimization because they have not yet been considered in the computation.

scholarly journals Numerical Simulation and Wind Tunnel Investigation on Static Characteristics of VAWT Rotor Starter with Lift-Drag Combined Structure

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6167
Author(s):  
Fang Feng ◽  
Guoqiang Tong ◽  
Yunfei Ma ◽  
Yan Li
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Speed Ratio ◽  
Static Characteristics ◽  
Torque Coefficient ◽  
Starting Characteristics ◽  
Static Torque

In order to get rid of the impact of the global financial crisis and actively respond to global climate change, it has become a common choice for global economic development to develop clean energy such as wind energy, improve energy efficiency and reduce greenhouse gas emissions. With the advantages of simple structure, unnecessary facing the wind direction, and unique appearance, the vertical axis wind turbine (VAWT) attracts extensive attention in the field of small and medium wind turbines. The lift-type VAWT exhibits outstanding aerodynamic characteristics at a high tip speed ratio, while the starting characteristics are generally undesirable at a low wind speed; thus, how to improve the starting characteristics of the lift-type VAWT has always been an important issue. In this paper, a lift-drag combined starter (LDCS) suitable for lift-type VAWT was proposed to optimize the starting characteristics of lift-type VAWT. With semi-elliptical drag blades and lift blades equipped on the middle and rear part outside the starter, the structure is characterized by lift-drag combination, weakening the adverse effect of the starter with semi-elliptical drag blades alone on the output performance of the original lift-type VAWT and improving the characteristics of the lift-drag combined VAWT. The static characteristic is one of the important starting characteristics of the wind turbine. The rapid development of computational fluid dynamics has laid a solid material foundation for VAWT. Thus the static characteristics of the LDCS with different numbers of blades were investigated by conducting numerical simulation and wind tunnel tests. The results demonstrated that the static torque coefficient of LDCS increased significantly with the increased incoming wind speed. The average value of the static torque coefficient also increased significantly. This study can provide guidelines for the research of lift-drag combined wind turbines.

scholarly journals Direct Numerical Simulation in Two Dimensional Homogeneous Isotropic Turbulence Using Spectral Method

2013 ◽  
Vol 5 (3) ◽  
pp. 435-445
Author(s):  
M. S. I. Mallik ◽  
M. A. Uddin ◽  
M. A. Rahman
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Flow Field ◽  
Direct Numerical Simulation ◽  
Spectral Method ◽  
Isotropic Turbulence ◽  
Qualitative Behavior ◽  
Two Dimensional ◽  
Homogeneous Isotropic Turbulence ◽  
Decaying Turbulence

Direct numerical simulation (DNS) in two-dimensional homogeneous isotropic turbulence is performed by using the Spectral method at a Reynolds number Re = 1000 on a uniformly distributed grid points. The Reynolds number is low enough that the computational grid is capable of resolving all the possible turbulent scales. The statistical properties in the computed flow field show a good agreement with the qualitative behavior of decaying turbulence. The behavior of the flow structures in the computed flow field also follow the classical idea of the fluid flow in turbulence. Keywords: Direct numerical simulation, Isotropic turbulence, Spectral method. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi:http://dx.doi.org/10.3329/jsr.v5i3.12665 J. Sci. Res. 5 (3), 435-445 (2013)  

scholarly journals Numerical simulation of flow field in umbrella wind turbine

2018 ◽  
Vol 153 ◽  
pp. 052062
Author(s):  
Bao Daorina ◽  
Wang Xiaoxue ◽  
Shang Wei ◽  
Liu Yadong ◽  
Bao Daorina ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Wind Turbine

Numerical Simulation of the Aerodynamic Performance of a H-Type Wind Turbine during Self-Starting

2014 ◽  
Vol 529 ◽  
pp. 296-302 ◽  
Author(s):  
Wei Zuo ◽  
Shun Kang
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Pitch Angle ◽  
Turbulence Modeling ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Time Dependent ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Sst Turbulence Model

The aerodynamic performance and the bypass flow field of a vertical axis wind turbine under self-starting are investigated using CFD simulations in this paper. The influence of pitch angle variations on the performance of the wind turbine during self-starting is presented. A two-dimensional model of the wind turbine with three blades is employed. A commercial software FlowVision is employed in this paper, which uses dynamic Cartesian grid. The SST turbulence model is used for turbulence modeling, which assumes the flow full turbulent. Based on the comparison between the computed time-dependent variations of the rotation speed with the experimental data, the time-dependent variations of the torque are presented. The characteristics of self-starting of the wind turbine are analyzed with the pitch angle of 0o、-2oand 2o. The influence of pitch angle variations on two-dimensional unsteady viscous flow field through velocity contours is discussed in detail.

scholarly journals Numerical Analysis of Design Parameters With Strong Influence on the Aerodynamic Efficiency of a Small-Scale Self-Pitch VAWT

2015 ◽  
Author(s):  
Carlos Xisto ◽  
José Páscoa ◽  
Michele Trancossi
Keyword(s):  
Wind Turbine ◽  
Strong Influence ◽  
Vertical Axis ◽  
Periodic Variation ◽  
Numerical Approach ◽  
Design Parameters ◽  
Speed Ratio ◽  
Small Scale ◽  
Vertical Axis Wind Turbine ◽  
Four Bar Linkage

In the paper, four key design parameters with a strong influence on the performance of a small-scale high solidity variable pitch VAWT (Vertical Axis Wind Turbine), operating at low tip-speed-ratio (TSR) are addressed. To this aim a numerical approach, based on a finite-volume discretization of two-dimensional Unsteady RANS equations on a multiple sliding mesh, is proposed and validated against experimental data. The self-pitch VAWT design is based on a straight blade Darrieus wind turbine with blades that are allowed to pitch around a feathering axis, which is also parallel to the axis of rotation. The pitch angle amplitude and periodic variation are dynamically controlled by a four-bar-linkage system. We only consider the efficiency at low and intermediate TSR, therefore the pitch amplitude is chosen to be a sinusoidal function with a considerable amplitude. The results of this parametric analysis will contribute to define the guidelines for building a full size prototype of a small scale turbine of increased efficiency.

scholarly journals Fractional Dynamics of Genetic Algorithms Using Hexagonal Space Tessellation

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
J. A. Tenreiro Machado
Keyword(s):  
Genetic Algorithm ◽  
Distance Measure ◽  
Dimensional Space ◽  
Fitness Function ◽  
Operating Conditions ◽  
Model Parameters ◽  
Fractional Dynamics ◽  
Fourier Domain ◽  
Two Dimensional ◽  
Percolation Phenomena

The paper formulates a genetic algorithm that evolves two types of objects in a plane. The fitness function promotes a relationship between the objects that is optimal when some kind of interface between them occurs. Furthermore, the algorithm adopts an hexagonal tessellation of the two-dimensional space for promoting an efficient method of the neighbour modelling. The genetic algorithm produces special patterns with resemblances to those revealed in percolation phenomena or in the symbiosis found in lichens. Besides the analysis of the spacial layout, a modelling of the time evolution is performed by adopting a distance measure and the modelling in the Fourier domain in the perspective of fractional calculus. The results reveal a consistent, and easy to interpret, set of model parameters for distinct operating conditions.

Prediction of Aerodynamic Noise Radiated From a Vertical-Axis Wind Turbine

2003 ◽  
Author(s):  
Akiyoshi Iida ◽  
Akisato Mizuno ◽  
Kyoji Kamemoto
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Sound Source ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Unsteady flow field and flow induced noise of vertical axis wind turbine are numerically investigated. The flow field is numerically calculated by the vortex method with core-spreading model. This simulation obtains aerodynamic performance and aerodynamic forces. Aerodynamic noise is also simulated by using Ffowcs Williams-Hawkings equation with compact body and low-Mach number assumptions. Tip speed of rotor blades are not so high, then the contribution of the moving sound source is smaller than that of the dipole sound source. Since the maximum power coefficient of VAWT can be obtained at lower tip-speed ratio compared to the conventional, horizontal axis wind turbines, the aerodynamic noise from vertical axis wind turbine is smaller than that of the conventional wind turbines at the same aerodynamic performance. This result indicates that the vertical axis wind turbines are useful to develop low-noise wind turbines.

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