Estimation of wind turbine blade aerodynamic performances computed using different numerical approaches

Although much employed, wind energy systems still present an open, contemporary topic of many research studies. Special attention is given to precise aerodynamic modeling performed in the beginning since overall wind turbine performances directly depend on blade aerodynamic performances. Several models different in complexity and computational requirements are still widely used. Most common numerical approaches include: i) momentum balance models, ii) potential flow methods and iii) full computational fluid dynamics solutions. Short explanations, reviews and comparison of the existing computational concepts are presented in the paper. Simpler models are described and implemented while numerous numerical investigations of isolated horizontal-axis wind turbine rotor consisting of three blades have also been performed in ANSYS FLUENT 16.2. Flow field is modeled by Reynolds Averaged Navier Stokes (RANS) equations closed by two different turbulence models. Results including global parameters such as thrust and power coefficients as well as local distributions along the blade obtained by different models are compared to available experimental data. Presented results include fluid flow visualizations in the form of velocity contours, sectional pressure distributions and values of power and thrust force coefficients for a range of operational regimes. Although obtained numerical results vary in accuracy, all presented numerical settings seem to slightly under-or over-estimate the global wind turbine parameters (power and thrust force coefficients). Turbulence can greatly affect the wind turbine aerodynamics and should be modeled with care

Optimization and integration of an electric ducted fan propulsion system

Rastući trend u pogledu istraživanja vezana za električni pogon nije zaobi- šao vazduhoplovnu granu industrije. Poslednjih godina, veliki broj svetskih kompanija i istraživačkih centara pokušava da razvije “zelen” pogon letelica. Takođe, ubrzanim razvojem električnih energetskih komponenti (elektromotori sa stalnim magnetima, litijum-polimerne baterije, mosfet tranzistori i sl.) stvorila se velika zastupljenost električnih vazduhoplovnih pogona u oblasti malih bespilotnih letelica. U skladu sa ovim trendom predmet istraživanja ove disertacije predstavljaju elektroventilatorski sistemi propulzora. U okviru istraživanja izvršen je detaljan pregled literature vezane za ventilatorske propulzore nakon čega su predstavljeni matematički modeli pojedinih komponen- ti sistema propulzora. Takođe su predstavljene i metode parametrizacije geomet- rijskog oblika propulzora B splajnovima i CST metodom kao i metaheuristički metodi optimizacije: genetski algoritmi i metod roja čestica. Pomoću definisanih modela i metoda razvijena je metodologija optimizaci- je elektroventilatorskog sistema propulzora koja je predstavljena kroz tri poje- dinačna primera kao i kroz integrisani primer optimizacije i integracije pro- pulzora na malu bespilotnu VTOL letelicu. Optimizacijom postojećeg propulzo- ra ukazano je na mogućnost poboljšanja njegovih performansi za određeni režim rada a razvijena je i metodologija za višekriterijumsku optimizaciju propulzora pogonjenim električnim pogonom za čije potrebe je stvorena i baza komercijalno dostupnih komponenata.The growing trend in terms of electric drive research did not bypass the aerospace industry. In recent years, a large number of world companies and research centers have been trying to develop a “green” aircraft propulsion system. Also, with the rapid development of electric power components (permanent magnet motors, lithium-polymer batteries, MOSFET transistors etc.) there is a large representation of electric aircraft propulsion in the field of small UAVs. In line with this trend the subject of research of this dissertation are electric ducted fan propulsion systems. Within the research a detailed review of literature considering fan propulsion systems is done after which the mathematical models of the propulsion system individual components are presented. Also, the methods for geometric shape parameterization via B-Splines and CST as well as the metaheuristic optimization methods: genetic algorithms and particle swarm optimization are presented. Using the defined methods and models an electric ducted fan optimization methodology is developed which is presented through three individual examples as well as an integral example of a small VTOL aircraft propulsion system optimization and integration. By the optimization of an existing propulsor the possibility of improving its performance for a certain design point is shown while a multiobjective optimization methodology of a propulsion system which is electrically driven is also developed for whose needs a database of commercially available components was created. For the purpose of experimental investigation, a propulsion test rig was developed with which the influence of the inlet geometry on a commercially available fan is examined and a numerical analysis via the finite volume method was done in order to obtain a qualitative insight in the propulsion system performance

VAWT optimization using genetic algorithm and CST airfoil parameterization

Vetroturbina sa vertikalnom osom Dareiusovog tipa optimizovana je primenom genetskih algoritama (GA). Oblik aeroprofila parametrizovan je pomoću Klasa-Oblik transformacionog (CST) metoda. Metod dvojne višestrujne cevi sa Gormont modifikacijom za dinamički slom uzgona je kori-ćen za određivanje performansi vetroturbine sa vertikalnom osom. Kad su numerički kodovi validirani sa dostupnim eksperimentalnim rezultatima, parametri aeroprofila su varirani kako bi se postigla optimalna vrednost funkcije cilja genetskog algoritma. PR Projekat Ministarstva nauke Republike Srbije, br. 35035.Darrieus type vertical axis wind turbine (VAWT) is optimized using the genetic algorithm (GA). The airfoil shape is parameterized using the Class-Shape Transformation (CST) method. The double multiple stream tube (DMST) method with the Gormont dynamic stall modification is used for the calculation of the VAWT performance parameters. Once the numerical codes are validated using available experimental results, the airfoil parameters are varied as to achieve the optimum value of the genetic algorithm fitness function

Influence of selected turbulence model on the optimization of a class-shape transformation parameterized airfoil

An airfoil was parameterized using the class-shape transformation technique and then optimized via genetic algorithm. The aerodynamic characteristics of the airfoil were obtained with the use of a CFD software. The automated numerical technique was validated using available experimental data and then the optimization procedure was repeated for few different turbulence models. The obtained optimized airfoils were then compared in order to gain some insight on the influence of the different turbulence models on the optimization result

Multi-objective constrained optimizations of VAWT composite blades based on FEM and PSO

Vetroturbine sa vertikalnom osom obrtanja predstavljaju privlačno oruđe za iskorišćenje energije vetra, naročito pogodno za male potrošače ili nepristupačne terene. Iako su jednostavne geometrije (ovde su pretpostavljene prave lopatice konstantnog aeroprofila), njihova aerodinamička analiza može biti izrazito složena. Metode proračunske mehanike fluida iskorišćene su za procenu aerodinamičkih performansi rotora. Rad daje pregled i ocenu mogućih strategija za izvršenje višekriterijumskih optimizacija tokom projektovanja lopatice vetroturbine sa vertikalnom osom obrtanja laminatne strukture koje se odnose na njene glavne strukturne parametre: redosled ređanja i broj slojeva laminata. Brojni proračuni strukture kompozitnih lopatica vetroturbine izvedeni su metodom konačnih elemenata. Višekriterijumske ograničene optimizacije rojem čestica, evolutivnim metodom, izvršene su u odnosu na: ukupnu masu lopatice, najveće pomeranje strukture lopatice pri statičkom opterećenju, proračunate sopstvene frekvencije i kriterijum loma po lopatici. Kombinacijom različitih ulaznih i izlaznih parametara (ciljnih funkcija i ograničenja) moguće je definisati veliki broj prihvatljivih, poboljšanih rešenja.Vertical-axis wind turbines (VAWTs) are attractive tools for wind energy extraction particularly suitable for small consumers or off-grid areas. Although their geometry is simple (here, rectangular blade of constant airfoil is assumed), aerodynamic analysis may be quite complex. Computational fluid dynamics (CFD) approach is employed for the estimation of rotor aerodynamic performances. This paper provides a review of possible multi-objective optimization strategies for the design of small-scale VAWT laminate blades in terms of its main structural parameters: ply-order and ply-number. Numerous structural analyses of the composite turbine blades were performed by finite element method (FEM). Multi-criteria constrained optimizations, by an evolutionary method - particle swarm optimization (PSO), were performed with respect to blade total mass, maximum blade tip deflection under static loading, computed natural frequencies and failure index along the blade. By combining different input and output parameters (cost functions and constraints) a large variety of feasible solutions can be achieved

Multi-objective constrained optimizations of VAWT composite blades based on FEM and PSO

Vetroturbine sa vertikalnom osom obrtanja predstavljaju privlačno oruđe za iskorišćenje energije vetra, naročito pogodno za male potrošače ili nepristupačne terene. Iako su jednostavne geometrije (ovde su pretpostavljene prave lopatice konstantnog aeroprofila), njihova aerodinamička analiza može biti izrazito složena. Metode proračunske mehanike fluida iskorišćene su za procenu aerodinamičkih performansi rotora. Rad daje pregled i ocenu mogućih strategija za izvršenje višekriterijumskih optimizacija tokom projektovanja lopatice vetroturbine sa vertikalnom osom obrtanja laminatne strukture koje se odnose na njene glavne strukturne parametre: redosled ređanja i broj slojeva laminata. Brojni proračuni strukture kompozitnih lopatica vetroturbine izvedeni su metodom konačnih elemenata. Višekriterijumske ograničene optimizacije rojem čestica, evolutivnim metodom, izvršene su u odnosu na: ukupnu masu lopatice, najveće pomeranje strukture lopatice pri statičkom opterećenju, proračunate sopstvene frekvencije i kriterijum loma po lopatici. Kombinacijom različitih ulaznih i izlaznih parametara (ciljnih funkcija i ograničenja) moguće je definisati veliki broj prihvatljivih, poboljšanih rešenja.Vertical-axis wind turbines (VAWTs) are attractive tools for wind energy extraction particularly suitable for small consumers or off-grid areas. Although their geometry is simple (here, rectangular blade of constant airfoil is assumed), aerodynamic analysis may be quite complex. Computational fluid dynamics (CFD) approach is employed for the estimation of rotor aerodynamic performances. This paper provides a review of possible multi-objective optimization strategies for the design of small-scale VAWT laminate blades in terms of its main structural parameters: ply-order and ply-number. Numerous structural analyses of the composite turbine blades were performed by finite element method (FEM). Multi-criteria constrained optimizations, by an evolutionary method - particle swarm optimization (PSO), were performed with respect to blade total mass, maximum blade tip deflection under static loading, computed natural frequencies and failure index along the blade. By combining different input and output parameters (cost functions and constraints) a large variety of feasible solutions can be achieved

Numerical analysis of a hypersonic turbulent and laminar flow using a commercial cfd solver

Computational fluid dynamics computations for two hypersonic flow cases using the commercial ANSYS FLUENT 16.2 CFD software were done. In this paper, an internal and external hypersonic flow cases were considered and analysis of the hypersonic flow using different turbulence viscosity models available in ANSYS FLUENT 16.2 as well as the laminar viscosity model were done. The obtained results were after compared and commented upon

Analysis of TRWP particle distribution in urban and suburban landscapes, connecting real road measurements with particle distribution simulation

This article deals with methods and measurements related to environmental pollution and analysis of particle distribution in urban and suburban landscapes. Therefore, an already-invented sampling method for tyre road wear particles (TRWP) was used to capture online emission factors from the road. The collected particles were analysed according to their size distribution, for use as an input for particle distribution simulations. The simulation model was a main traffic intersection, because of the high vehicle dynamic related to the high density of start–stop manoeuvres. To compare the simulation results (particle mass (PM) and particle number (PN)) with real-world emissions, measuring points were defined and analysed over a measuring time of 8 h during the day. Afterwards, the collected particles were analysed in terms of particle shape, appearance and chemical composition, to identify the distribution and their place of origin. As a result of the investigation, the appearance of the particles showed a good correlation to the vehicle dynamics, even though there were a lot of background influences, e.g., resuspension of dust. Air humidity also showed a great influence on the recorded particle measurements. In areas of high vehicle dynamics, such as heavy braking or accelerating, more tyre and brake particles could be found

Production process of composite propeller for multirotor UAV

The application of composite materials in the aerospace industry has begun since the middle of the 20th century. Their use in various elements of aircraft constructions has extended over time. Primary load carrying elements of some aircraft constructions are made of composite materials due to their excellent mechanical properties as well as the good strength-to-weight ratio. Propellers and fan blades of jet engines are increasingly made of high-quality composite materials. Besides the mechanical properties of the material, production technology has a great impact on composite structure quality. The production process of two-bladed composite propeller is presented in this paper. Manufacturing of composite propeller for multirotor UAV application with suitable technology and relatively cheap materials is the main motive of this work. According to this motive, both (upper and lower) shells of the propeller are made of balanced plain weave glass fiber with epoxy matrix. The vacuum infusion process is used for shell manufacturing. After the polymerization process of shells (24h, 25°C), unidirectional carbon fabric reinforcements in the root zone and expanding polyurethane core are added during the bonding process. Then, the bonded propeller was cured 4h at 70°C. The high production process quality of the two-bladed propeller with the previously described technology is partly confirmed in this paper. Namely, the checking of propeller geometry and comparison with the CAD model was performed. Results of that comparison showed that a high degree of agreement between produced and CAD model was obtained. Comparison of static test and numerical structural analysis could be subjects of future work. That would provide the final validation of manufacturing technology quality which is described in this paper

Modeling, simulation and control of propeller driven seesaw system with asymmetric geometry using PID controller

Various algorithms are used to control modern unmanned aerial systems. However, thanks to the simplicity of application, the most commonly used control algorithm for aircraft but also for other dynamic systems in various industries is the PID (Proportional, Integral, Derivative) controller. For the proper response of the system and fast stabilization during the action of certain disturbances during its operation, it is necessary to precisely adjust the parameters of the PID controller. This paper presents a mathematical model of a seesaw system for which a PID control simulation was performed for different asymmetric geometries. Asymmetric geometry implies different positions of the rotor relative to the axis of system rotation, as well as when the rotor disks do not lie in the same plane, which simulates the influence of inaccuracy in the construction of multi-rotor UAVs. The control simulation shows the possibility of compensating for the mentioned geometric irregularities to ensure the appropriate behavior of the system. The limit values of this influence are also shown, at which the PID control algorithm cannot adequately perform the correction and ensure the correct response of the system. The obtained simulation results would be verified by making an adequate physical model and obtaining experimental results for the same input parameters, which may be the subject of future research work