Investigation of problems in modeling critical loads on a composite model of a wind turbine blade

This article deals with the problems of designing and analysis of the deformed state of the wind turbine blade under critical loads. A three-dimensional shell simulation model is built, taking into account the complex curvilinear geometry and the presence of reinforcing internal parts. The determination of the parameters of the stress-strain state under the influence of wind load was carried out on the basis of the finite element method. A shell ten-node isoparametric finite element was used. The constructed finite element model of the blade allows taking into account the composite structure and reproduced the presence of a different number of composite layers along the thickness of the shell, the diversity of fibers on individual layers, in particular, the curvilinear orthotropy of mechanical properties was modeled. The procedure of multi-layer structure setting is presented, which provides for superimposition of layers of composite one on the other in places of joint, which ensures compliance of model with technological peculiarities. Static analysis of structural deformation calculation is carried out taking into account lifting force and air head force. The strength analysis was performed for each of the layers according to the criterion of maximum deformations. Key words: composite material, wind turbine blade, strength, finite-elemental analysis, orthotropy of characteristics.

A comparison between aeroacoustic source mapping techniques for the characterisation of wind turbine blade models with microphone arrays

<p class="Abstract">Characterising the aeroacoustic noise sources generated by a rotating wind turbine blade provides useful information for tackling noise reduction of this mechanical system. In this context, microphone array measurements and acoustic source mapping techniques are powerful tools for the identification of aeroacoustic noise sources. This paper discusses a series of acoustic mapping strategies that can be exploited in this kind of applications. A single-blade rotor was tested in a semi-anechoic chamber using a circular microphone array. <br />The Virtual Rotating Array (VRA) approach, which transforms the signals acquired by the physical static array into signals of virtual microphones synchronously rotating with the blade, hence ensuring noise-source stationarity, was used to enable the use of frequency domain acoustic mapping techniques. A comparison among three different acoustic mapping methods is presented: Conventional Beamforming, CLEAN-SC and Covariance Matrix Fitting based on Iterative Re-weighted Least Squares and Bayesian approach. The latter demonstrated to provide the best results for the application and made it possible a detailed characterization of the noise sources generated by the rotating blade at different operating conditions.</p>

Study on Structural Performance of Horizontal Axis Wind Turbine with Air Duct for Coal Mine

Considering the characteristics of narrow underground space and energy distribution, based on blade element momentum theory, Wilson optimization model and MATLAB programming calculation results, the torsion angle and chord length of wind turbine blade under the optimized conditions were obtained. Through coordinate transformation, the data were transformed into three-dimensional form. The three-dimensional model of the blade was constructed, and the horizontal axis wind turbine blade under the underground low wind speed environment was designed. The static structural analysis and modal analysis were carried out. Structural design, optimization calculation and aerodynamic analysis were carried out for three kinds of air ducts: external convex, internal concave and linear. The results show that the velocity distribution in the throat of linear air duct is relatively uniform and the growth rate is large, so it should be preferred. When the tunnel wind speed is 4.3 m/s and the rated speed is 224 rad/s, the maximum displacement of the blade is in the blade tip area and the maximum stress is at the blade root, which is not easy to resonate. The change rate of displacement, stress and strain of blade is positively correlated with speed. The energy of blade vibration is mainly concentrated in the swing vibration of the first and second modes. With the increase in vibration mode order, the amplitude and shape of the blade gradually transition to the coupling vibration of swing, swing and torsion. The stress and strain of the blade are lower than the allowable stress and strain of glass fiber reinforced plastics (FRP), and resonance is not easy to occur in the first two steps. The blade is generally safe and meets the design requirements.

Perancangan Bilah Turbin Angin Jenis Taperless Untuk Pesisir Pantai Utara Jawa Barat Menggunakan Perangkat Lunak QBlade

Energy needs in Indonesia continue to increase, while the availability of non-renewable energy sources is decreasing and is exacerbated by the increasing use of fuels that are not environmentally friendly, so efforts are needed to find alternative uses of renewable energy that are renewable and environmentally friendly. The Cirebon coast has good wind conditions which can be used to create renewable energy sources through the wind. This study aims to utilize the energy that is already available by designing a horizontal wind turbine blade. The method used starts from literature study, selecting airfoils, analyzing data, selecting the best airfoils, analyzing the best airfoils and ending with design drawings. The initial data used as the initial design is the Cirebon City wind data which has the highest average wind speed of 9 m/s. This study designed a horizontal wind turbine blade using QBlade Software with 3 types of NACA, NACA 4415, 6412 and 6415. NACA 6415 has a power coefficient of 0.40%, the highest coefficient is then obtained NACA 6412 with a coefficient of 0.41%, and The highest power coefficient was obtained by NACA 4415 with a coefficient of 44%

Fluid and Structure Analysis of Wind Turbine Blade with Winglet

One of the succeeded methods to enhance the performance of horizontal axis wind turbine (HAWT) is an attaching a winglet to the blades tip. The current paper study the effect of four key parameters that are used to describe the winglet on the performance of wind turbine which are winglet height H%R, cant angle θ, twist angle β, and taper ratio Λ. A five design cases for each geometric parameters were numerically investigated using computational fluid dynamics (CFD) by ANSYS18.1 software, which totally give a twenty different response. A validation of present computational model with reference experimental results successfully carried out with maximum inconsistency of 3%. A mathematical correlation was established from the CFD results and being used in predicting the turbine power for the different winglet geometric parameters. From CFD and mathematical correlation response, the effect of H and θ were greater than β and Λ on the turbine power. The epoxy E-glass unidirectional material was selected for current study to investigate the effect of winglet on blade structure. The power increases by 2% to 30% due to adding winglet to a wind turbine blade. The maximum power increment corresponds to the design case of W6 with H= 8%R, =30°, β = 3°, and Λ = 0.8. Form the structural analysis the addition of winglet changes the stress distribution over the blade, increasing stresses at the blade root, and achieved the transfer of the maximum deformation from the blade tip to the winglet tip.