Vertical Axis Of Rotation Research Articles

SHAFT BEARING OF WIND TURBINE WITH VERTICAL AXIS OF ROTATION

This article describes a new design solution for a hybrid bearing intended for use in prosumer wind turbines with a vertical axis of rotation of the turbine rotor. The automatic rotational speed-dependent load-switching, lubrication and cooling systems applied in the hybrid bearing ensure a particularly long service life and highly quiet running while maintaining high energy efficiency over the full rotational speed range of shafts with turbine rotors. The hybrid bearing design has been adapted to the use of lubricating fluids with the lowest possible viscosity, including oil-water emulsions and even water itself. The use of water as a lubricant makes the bearing system highly environmentally friendly and completely fire-safe.

Virtual Reality, Autostereoscopy, and Physical Models for Learning Anatomy: Performance Comparisons

IntroductionTraditional anatomical education relies on textbooks, physical models, and cadaveric specimens. Advances in technology have provided other display modalities including virtual reality (VR), and autostereoscopic displays. VR uses head‐mounted displays (HMDs) for an interactive experience and autostereoscopic screens, like AlioscopyTM, offer a stereoscopic but HMD‐free environment. Current research shows contradictory results on the efficacy of VR compared to physical models, and there appears to be no data on the efficacy of autostereoscopic displays in learning anatomy. The purpose of this study is to determine whether VR, AlioscopyTM, or physical models yield the best performance for anatomical education.MethodsStudents at McMaster University without prior anatomy training will learn nominal skeletal anatomy in three different modalities: VR (Oculus Quest 2TM), AlioscopyTM, or a physical 3D‐printed bone model. Each of the environments will be as identical as possible (i.e, the VR environment is a rendering of the exact room and set‐up used for testing the physical bone models). Participants will be randomized to one of three interventions where they will study ten bony landmarks on either the human hemipelvis, zygomatic bone, or calcaneus in a distinct modality. Participants will be seated and use an XboxTM controller to rotate the bone along the vertical axis of rotation. After four minutes, an untimed, recognition‐based test will be administered, where participants will be given a 3D‐printed bone identical to the one used in the learning phase, with randomized landmarks and word bank of landmarks learnt. Performance will be evaluated based on landmarks correctly identified on the recognition‐based test.ResultsBased on the current literature, we hypothesize that the physical models will be a superior learning environment compared to the VR environment. However, significant improvements in the HMD of the Oculus Quest 2 may have ameliorated previous issues with the VR environment. There is no data available on the efficacy of AlioscopyTM and while the absence of an HMD is appealing, its narrow viewing angle compared to the immersive VR environment may be problematic.ConclusionWith the push to increase accessibility and decrease costs associated with anatomical education with the help of digital modalities, the findings from this study are critical to informing teaching practices, and technology use in anatomy education.

EXPERIMENTAL STUDY OF AERODYNAMIC CHARACTERISTICS AND EVALUATION OF WIND FLOW CONCENTRATOR EFFICIENCY

An experimental study of the wind flow concentrator of a new design using the wind tunnel of subsonic speeds was carried out. Experimental studies in the wind tunnel were performed at an air flow velocity of 1 m/s. The fields of velocity and pressure distribution in the areas in front of the wind flow concentrator and in its central part are obtained. Based on the obtained data in the Mathcad, contour graphs are constructed, which show the distribution of wind flow velocities and pressures in the investigated part of the wind flow concentrator. As a result, it was obtained that in the area of the wind turbine blades there is an increase in the velocity of air masses by 4 times compared to the air velocity at the entrance to the wind flow concentrator. The proposed design of the wind flow concentrator makes it possible to increase the efficiency of the wind turbine and receive electric energy at low wind speeds, when the bladed wind turbines do not generate electricity. Verification of experimental data with data of numerical modeling of hydrodynamics in the wind flow concentrator is carried out. The evaluation of the use of wind flow concentrator to increase the efficiency of wind turbines with a vertical axis of rotation is carried out.

Still room for improvement in traditional 3D interaction: selecting the fixed axis in the virtual trackball

Virtual trackball techniques are widely used when 3D interaction is performed through interfaces with a reduced number of degrees of freedom such as mice and touchscreens. For decades, most implementations fix a vertical axis of rotation, which is a suitable choice when the vertical axis should indeed be fixed, according to some mental model of the user. We conducted an experiment involving the use of a mouse and a touch device to study usability in terms of performance, perceived usability and mental workload when selecting different fixed axes in accordance with the user’s mental model. The results we obtained indicate that the consistency between the axis fixed by the technique and the object’s intrinsic axis has a positive effect on usability. We believe that implementations that allow to select different fixed axis for each specific object should be considered when designing future reduced-DoF interaction interfaces.

Optimization of a vertical axis wind turbine with a deflector under unsteady wind conditions via Taguchi and neural network applications

Vertical axis wind turbines (VAWTs), so named because of their vertical axis of rotation, are a sustainable, opportune, and versatile means of producing energy. Their operation is not dependent on wind direction, making them suitable for use in settings with turbulent and inconsistent winds (e.g., urban locations), and they can be installed at the bottom of towers for easier installation and maintenance. However, unsteady wind may cause a vertical axis wind turbine (VAWT) to operate under drag-controlled conditions and reduce its performance. The power coefficient of a VAWT under unsteady wind conditions is heavily impacted by the tip speed ratio (TSR). Understanding and optimizing TSR is critical to making VAWTs a more viable and attractive option for sustainable energy production. Deflectors have been shown to improve the aerodynamic performance of wind turbines. In the present study, the Taguchi method is used in the experimental design, and a high-fitting neural network (NN) model based on computational fluid dynamics (CFD) data is adopted to predict the optimal mean TSR for a VAWT operation with a deflector. The amplitude and frequency fluctuations of the mean inlet velocity are used to specify the unsteady wind conditions. The results show that the imposed unsteady wind reduces the average power coefficient (Cp-) of the VAWT. By applying the Taguchi method and NN analysis to the impact of unsteady wind conditions, it is found that the mean TSR (TSRmean) is the factor producing the greatest impact on Cp-. The optimal TSRmean is evaluated by the NN model. In light of the recommendation from the NN predictions, the Cp- value from CFD can be improved by up to 3.58 folds under the optimal TSRmean. Furthermore, the relative errors of predicted Cp- values between the NN and CFD simulation are less than 4%, showing the reliability of predictions of the developed NN model in efficiently calculating the optimal operation for a VAWT.

Application Use of the HP Multijet Fusion Technology in the Rapid Prototyping of Wind Turbines with a Vertical Axis of Rotation

Abstract The article presents steps to be taken when designing a wind turbine with a vertical axis of rotation, based on the modification of the Savonius engine structure. The HP MultiJet Fusion additive manufacturing technology was used and discussed to generate experimental models. The results of numerical and experimental studies of the analyzed geometry of wind turbines, carried out at the Rapid Prototyping Laboratory and the Laboratory of Energy Machines, at the Department of Mechanics and Fundamentals of Machine Design, University of Warmia and Mazury in Olsztyn are presented.

Development of the Design of the Working Body of a Rotary Tiller with a Vertical Rotation Axis

Development of the Design of the Working Body of a Rotary Tiller with a Vertical Rotation Axis

To the Question of Fastening Active Working Bodies to the Rotors of Milling Cutters with a Vertical Rotation Axis

To the Question of Fastening Active Working Bodies to the Rotors of Milling Cutters with a Vertical Rotation Axis

Assessment of natural resource potential of territories disturbed by mining works in the context of effective use of post-technogenic landscape

In the article, the concepts of natural resource potential, post-technogenic landscape, and anthropogenic transformation are defined. The difference between quantitative and qualitative changes in the natural ecological system is considered. The types of resource waste and natural resources promising for use are analyzed. An assessment of the natural resource potential of the territories affected by mining operations is presented. The assessment is carried out on the example of the Kryvyi Rih iron ore complex. The use of renewable energy sources is considered as the most important prospects for the development of post-technogenic landscapes in mining regions, the main advantages of using renewable energy sources are determined. In the context of the effective use of post-technogenic landscapes, the potential of solar energy and wind power plants (wind turbines) was investigated. Calculations of the efficiency of the use of renewable energy sources in the territories disturbed by mining operations are given. A comparison of the efficiency of wind turbines (electricity production) in the conditions of Kryvbas dump sites with vertical and horizontal wind power plants is made taking into account the height of the location. Evidence is presented regarding the feasibility of using windmills with a vertical axis of turbine rotation. It is established that vertical wind power plants can produce electricity 7 times more than traditional (horizontal) ones. The main factors that determine the need for the development of non-traditional sources of energy in Ukraine are determined. The possibility of using post-technogenic landscapes for nature conservation, recreational and tourist purposes is considered. Examples of the use of the natural resource potential of territories disturbed by mining operations during open-pit mining operations are given, and the use of disturbed lands in the coal industry is discussed. Possibilities of involving post-technogenic landscapes in the economic activity of mining regions are considered. In the article, the authors prove that the degree of transformation of the natural resource potential of territories disturbed by mining operations determines the possibility of reclamation or use of these territories for the needs of society. Keywords: natural resource potential, territories affected by mining operations, landscape transformation, renewable energy sources, solar energy, wind power plants, vertical windmills, horizontal windmills, reclamation of territories, use of post-technogenic landscapes, man-made landscape.

П Р О М Ы С Л О В Ы Е В Е Т Р Я Н Ы Е Э Л Е К Т Р О С ТА Н Ц И И ДЛЯ ДОБЫЧИ ТЯЖЕЛОЙ НЕФТИ И ПРИРОДНЫХ БИТУМОВ

Available oil fields are being depleted. But explored reserves of heavy oil and natural bitumen in the world are known to be at least 5.6 trillion barrels, which is about 2 times more than discovered reserves of conventional oil. To produce these hy- drocarbons, the formation must be heated to greatly reduce the viscosity of heavy oil and bitumen. Existing methods use superheated steam to heat the formation for 2-6 months. Steam is generated using natural gas and clean water. This leads to the release of carbon dioxide into the atmosphere and to the deple- tion of rivers. To reduce the damage to nature, it is proposed to heat the formation simultaneously with steam and electrical current passing through the formation. It is proposed to use the electricity of the field wind farms designed with a vertical axis of rotation of the turbine. The design scheme of the station pro- vides stability in storm winds without a foundation, it can be mounted in 3-4 days, it is transportable and much less expensive than turbines with a horizontal axis of rotation. The technical characteristics of such field wind farms are discussed.

КИНЕМАТИЧЕСКОЕ ИССЛЕДОВАНИЕ САДОВОЙ ПОЧВООБРАБАТЫВАЮЩЕЙ ФРЕЗЫ С ПЛАНЕТАРНЫМ ПРИВОДОМ

It has been established that cutters with a vertical rotation axis meet the mentioned requirements. As a result of their updating, a cutting machine with planetary mechanism with external gearing is recommended, which provides a large rotation number of the knife disk at low rotor speeds. Kinematic analysis of the transmission mechanism has been carried out, analytical expressions have been derived to determine the trajectory, speed, acceleration of the knife depending on the rotor frequency and gear ratio of the mechanism.

Improving the efficiency of carousel wind turbine using aerodynamic shield

The problem of increasing the efficiency of using the oncoming air flow for a wind wheel with a vertical axis of rotation, which is a mechanical drive of the wind heat generator, is considered. It is proposed to increase the efficiency of the device by installing an aerodynamic shield for the air flow oncoming the wind wheel. Such a shield is a cylindrical body in which a heat generator is placed. The shield creates an effect of confuser, leading to an increase in the speed and, consequently, in the kinetic energy of the air flow acting on the rotor blades. It is shown experimentally that the presence of an aerodynamic shield under the conditions of the experiments carried out at an incoming air flow velocity of ~ 1 m/s leads to a practical doubling of the wind wheel torque.

GENERALIZED MATHEMATICAL MODEL OF VIBRATIONS OF A VERTICAL AXIS ROTARY SYSTEM

The rotor’s response to dynamic actions depends on its physical parameters and the parameters of the supporting structure. The vibration measured on the bearings or on the rotor shaft, in addition to the physical properties of the rotor, also depends on the value of the unbalance, its distribution along the rotor axis, as well as on the rotational speed. These factors influence the choice of the balancing method. This article proposes a dynamic model of a rotary machine with a vertical axis of rotation and six degrees of freedom. Differential equations of free and forced oscillations of the rotor system are compiled. It is shown that when considering the general case of oscillations of the rotor system, there is a high connectivity of oscillations along all generalized coordinates. Based on the analysis of differential equations, ways of reducing vibration activity and connectivity of machine vibrations are shown, which provide for: reduction of the center of mass of the platform to the axis of rotation of the rotor; alignment of the center of stiffness of the elastic support system with the center of gravity of the platform, and the main axes of stiffness and constant viscous friction of dampers with the main central axes of inertia of the platform; the use of vertical suspensions for the oscillating system in the construction of the machine; replacement of the elastic sealing diaphragm of the rotor with a non-rigid one. The above measures to reduce the connectivity of vibrations and vibration activity do not completely eliminate the vibrations of the machine caused by stochastic, variable imbalances. Therefore, a further decrease in the vibration activity of the machine can be associated with the use of auto-ballasting devices, which make it possible to reduce the disturbing forces by reducing the magnitude of the stochastic imbalances of the rotary machine.

The comparison of dual axis photovoltaic tracking system using artificial intelligence techniques

<span>In this paper, the efficiency of photovoltaic panels is improved by adding a sun tracking system. The solar tracking system is used for tracking the sun so that photovoltaic always faces the sun. This system uses a dual axis consisting of horizontal rotation axis and a vertical rotation axis. The horizontal rotational axis motion is to follow the azimuth angle of the sun from north to south. Then, to follow the sun's azimuth angle from east to west is the vertical axis motion. Both types of movements are controlled using a PID controller that is optimized with an artificial intelligence approach, namely particle swarm optimization (PID-PSO), firefly algorithm (PID-FA), imperialist competitive algorithm (PID-ICA), bat algorithm (PID-BA), and ant colony optimization (PID-ACO). Experiments of various approaches were carried out and the corresponding performance compared. The experimental results show that PID-BA performs best in terms of settling time and overshoot. The results also allow the comparison of different PID controller and the calculation of the fastest completion time.</span>

Microstructure and Crystallographic Preferred Orientations of an Azimuthally Oriented Ice Core from a Lateral Shear Margin: Priestley Glacier, Antarctica

A 58 m long azimuthally oriented ice core has been collected from the floating lateral sinistral shear margin of the lower Priestley Glacier, Terra Nova Bay, Antarctica. The crystallographic preferred orientations (CPO) and microstructures are described in order to correlate the geometry of anisotropy with constrained large-scale kinematics. Cryogenic Electron Backscatter Diffraction analysis shows a very strong fabric (c-axis primary eigenvalue ∼0.9) with c-axes aligned horizontally sub-perpendicular to flow, rotating nearly 40° clockwise (looking down) to the pole to shear throughout the core. The c-axis maximum is sub-perpendicular to vertical layers, with the pole to layering always clockwise of the c-axes. Priestley ice microstructures are defined by largely sub-polygonal grains and constant mean grain sizes with depth. Grain long axis shape preferred orientations (SPO) are almost always 1–20° clockwise of the c-axis maximum. A minor proportion of “oddly” oriented grains that are distinct from the main c-axis maximum, are present in some samples. These have horizontal c-axes rotated clockwise from the primary c-axis maximum and may define a weaker secondary maximum up to 30° clockwise of the primary maximum. Intragranular misorientations are measured along the core, and although the statistics are weak, this could suggest recrystallization by subgrain rotation to occur. These microstructures suggest subgrain rotation (SGR) and recrystallization by grain boundary migration recrystallization (GBM) are active in the Priestley Glacier shear margin. Vorticity analysis based on intragranular distortion indicates a vertical axis of rotation in the shear margin. The variability in c-axis maximum orientation with depth indicates the structural heterogeneity of the Priestley Glacier shear margin occurs at the meter to tens of meters scale. We suggest that CPO rotations could relate to rigid rotation of blocks of ice within the glacial shear margin. Rotation either post-dates CPO and SPO development or is occurring faster than CPO evolution can respond to a change in kinematics.

HYBRID SYSTEM OF DUAL AXIS PHOTOVOLTAIC TRACKING SYSTEM USING PID-CES-ACO

In this paper, the efficiency of photovoltaic panels is improved by adding two solar tracking systems. The solar tracking system is used to track the sun so that the photovoltaic always faces the sun. This system uses a dual axis consisting of a horizontal rotation axis and a vertical rotation axis. The motion of the horizontal axis of rotation follows the sun's azimuth angle from north to south. The motion of the vertical axis of rotation following the sun's azimuth angle from east to west is the vertical axis motion. Both types of movement are controlled using PID and Fuzzy controllers which are optimized with an artificial intelligence approach, namely Ant Colony Optimization (ACO). Experiments with PID control approach and CES control were optimized using the ACO method (Hybrid PID-CES-ACO method). In this research, PID-CES-ACO was the best model, obtained on the horizontal axis of overshot 1328 pu, the smallest undershot was 0.116, and the fastest settling time was 0.183 s, on the vertical axis the smallest overshot was 1.246 pu, the smallest undershot was 0.044, the fastest settling time was 0.163 s

An innovative technical solution to the issue of conditioning forage grasses

Acceleration of wilting of forage grasses treated during mowing by the working bodies of dynamic conditioners installed on disc mowers is a prerequisite for improving the quality of forage, primarily in terms of the concentration of high-quality protein, vitamins and other biologically active substances, as well as energy. The main working body of modern conditioning devices is a horizontal shaft rotating at a speed of 18-29 m / s with hinged beaters of various configurations placed on its surface, which ensure grass dragging along the surface of corrugated decks, through combs, etc. [1]. Such devices significantly increase the weight of the mowers, which increases their cost by about 1/3, and the use of an additional drive of the conditioner shaft leads to operational difficulties. In this regard, the search for innovative technical solutions aimed at improving this situation is a very urgent task. The article describes the design and principle of operation of a rotary conditioner with a vertical axis of rotation developed in Federal Williams Research Center of Forage Production & Agroecology for the KR-2.1M mower of the “Agramak” company, the articulated beams of which are installed directly on its discs. The mower with an innovative conditioner was tested on a mixture of reed fescue with clover of the first cut and on tetraploid meadow fescue of the second. The yield of green mass, the composition of the herbage, its height and lodging, as well as the phase of development were determined in accordance with the guidelines for conducting field experiments with forage crops. The work of the mower was evaluated according to GOST 28722-90. The article presents data on the degree of damage to treated plants and the dynamics of the rate of their dehydration.

Experimental investigation of the wake characteristics behind twin vertical axis turbines

Vertical axis wind and tidal turbines are a promising technology, well suited to harness kinetic energy from highly turbulent environments such as urban areas or rivers. The power density per occupied land area of two or three vertical axis rotors deployed in close proximity can notably exceed that of their horizontal axis counterparts. Using acoustic Doppler velocimetry, the three-dimensional wake developed downstream of standalone and twin vertical axis turbines of various shaft-to-shaft distances and rotational direction combinations was characterised in terms of mean velocity and turbulence statistics, with their impact on momentum recovery quantified. Results show that the wake hydrodynamics were more impacted by turbine rotational direction than lateral distance between devices for the range of lateral spacing considered. In the cases with turbines operating in a counter-rotating forward configuration, the wake mostly expanded laterally and attained the largest velocities that exceeded those in the single turbine case, with full momentum recovery at 5 turbine diameters downstream. The wake developed by the counter-rotating backward setup notably extended over the vertical direction, whilst devices rotating in the same direction featured the greatest lateral wake expansion with reduced velocities. Linear wake superposition of the single turbine wake provided a good representation of the mean velocity field behind twin-turbine setups. The presented results indicate that, in the design of twin-turbine arrays moving in counter-rotating forward direction, a lateral spacing of, at least, two turbine diameters should be kept as this allows the kinetic energy in the wake to be fully recovered by five turbine diameters downstream.

CFD МОДЕЛЮВАННЯ АЕРОДИНАМІЧНОГО ПОТОКУ У ВІТРЯНІЙ ТУРБІНІ З ВЕРТИКАЛЬНОЮ ВІССЮ ОБЕРТАННЯ І КОНЦЕНТРАТОРОМ ВІТРОВОГО ПОТОКУ

In order to improve the aerodynamic characteristics by increasing the energy of the wind flow of wind turbines with a vertical rotational axis, a special device - wind flow concentrator was proposed. The concentrator contains channels with a curved contour, which are installed around the rotor. To study the hydrodynamic parameters of the wind flows concentrator depending on the ratio between the input and output geometric characteristics of the channels, as well as the angles of entry and exit methods of mathematical modeling are used. Based on the method of quadratic rotational design of orthogonal combinations, using three-dimensional numerical simulation, the aerodynamic characteristics of the wind flow concentrator for a vertical axis wind turbine were investigated.

Measurement of surface deformation and cohesion of a granular pile under the effect of centrifugal force

An experimental apparatus measuring free-surface deformation of a centrifuged granular pile is developed. By horizontally rotating a quasi two-dimensional granular pile whose apex is located at the vertical rotation axis, the resultant force of gravity and centrifuge yields the deformation of the granular pile. In this setup, centrifugal force depends on distance from the rotation axis whilst gravitational force is constant everywhere. Therefore, free-surface deformation by various centrifuge degrees can be systematically examined using this apparatus. In the system, a small unit consisting of a camera and computer is rotated with the granular sample to record the rotation-induced deformation. To evaluate the validity of the system, deformation of a rotated water surface is first measured and analyzed. The obtained data are properly explained by the theoretical parabolas without any fitting parameter. Next, we measure the deformation of non-cohesive and cohesive granular piles using the developed apparatus. Both granular samples show the significant deformation of granular pile and finally develop steep granular slopes on the side walls. However, details of the deformation processes depend on the cohesion strength. To quantitatively characterize the difference, the effective strength by cohesion and granular local-slope variations are analyzed based on the experimental results.