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Search results for: ROTORS
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The methods of technological machines’ rotors balance
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Product development using rapid prototyping for pump rotors
PublicationW artykule zaprezentowano zastowanie techniki szybkiego prototypowania do wytwarzania fizycznych modeli produktów i ich części składowych oraz prototypów funkcjonalnych, technicznych i wizualnych z pominięciem tradycyjnych technologii mechanicznych jak odlewanie, skrawanie czy też obróbko elektroerozyjna. Przedstawione studium przypadku oparto na rozwoju konstrukcji wirnika pompy począwszy od etapu projektowania poprzez wytwarzanie...
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DYNWIR S-70 program for modal analysis of multisupported and multimass rotors
PublicationThe article provides a brief description of the program Dynwir-S-70 (currently being developed in the Rotor Dynamics and Slide Bearings Department in the Institute of Fluid-Flow Machinery Polish Academy of Sciences in Gdansk) which is a program for analysis of multi-supported and multi-mass rotors. Used algorithms and the construction of mass and stiffness matrix were presented. Damping matrix structure based on Rayleigh damping...
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Possibilities of using SVC compensators for synchronous generators rotors oscillations damping.
PublicationThe article presents the idea of using static var compensators (SVC) for damping generators rotors oscillations. A novel SVC controller structure is proposed to provide better dynamic performance of the power system. A tests results are shown for proposed controller structure, that was carried out in a three-machine power system model as well as in multi-machine model of Polish Power System.
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Experimental Research Concerning Hydrodynamic Clutches Controlled by Increasing Distance Between Rotors
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Some problems of self-excited vibrations of turbine rotors. Part I: The theoretical method
PublicationPrzedstawiono teoretyczną metodę określania uszczelnienia nadbandażowego lub dławicy zupełnej, które odgrywa największą rolę w generowaniu samowzbudnych drgań typu aerodynamicznego wirników turbinowych. Drgania harmoniczne układu wirnika turbiny opisane są macierzowym równaniem, a wymuszenia aerodynamiczne określane metodą współczynników wpływu.
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Study on the Influence of an Axial Distance Between Rotors on a Performance of a Small Counter-Rotating Wind Turbine
PublicationIn this paper, results of the investigation on the performance of a small counter-rotating wind turbinehas been presented. Computational Fluid Dynamics methodshave been used forwind turbine simulations. Rotors representation were introduced into computational domain by means of Actuator Line Model. Influence of an axial distance of CRWTrotorshas been investigated. In all studied configurations rotors were counter-rotating...
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Contr-rotating eccentric-mass rotors used as exciters of sinusoidal forces applied to elastically supported bodies
PublicationThe work focuses on aspects of multibody dynamics. Investigated object is a mass driven by rotations of an inertial shaker. Resulting vibrational set consists of two counter-rotating identically-unbalanced rotors. Since the mass centres of the rotors do not coincide with the axes of their rotations, significant centrifugal forces arise during rotations. As both rotors are identically unbalanced, the inter-axial force components...
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Steroidal Molecular Rotors with 1,4-Diethynylphenylene Rotators: Experimental and Theoretical Investigations Toward Seeking Efficient Properties
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Some problems of self-excited vibrations of turbine rotors. Part II: Experimental identification of rotordynamic coefficients
PublicationPrzedstawiono wyniki eksperymentalnego wyznaczania współczynników sił aerodynamicznych generowanych w uszczelnieniu nadbandażowym, które powodują drgania wirników turbinowych. Badania przeprowadzono na powietrznej turbinie modelowej dla różnej częstości obrotów wału i różnego obciążenia turbiny.
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Dependence of Power Characteristics on Savonius Rotor Segmentation
PublicationSavonius rotors are large and heavy because they use drag force for propulsion. This leads to a larger investment in comparison to horizontal axis wind turbine (HAWT) rotors using lift forces. A simple construction of the Savonius rotor is preferred to reduce the production effort. Therefore, it is proposed here to use single-segment rotors of high elongation. Nevertheless, this rotor type must be compared with a multi-segment...
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Numerical investigation on the performance of a small counter-rotating wind turbine
PublicationThe article presents the results of the investigation on the performance of a small counter-rotating wind turbine. The wind turbine has been simulated using Computational Fluid Dynamics methods. Actuator Line Model has been successfully used to represent rotors in the computational domain. A parametric study has been carried out, taking into account changes in the tip speed ratio of the rotors while maintaining a constant distance...
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Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine
PublicationA small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performancehas been investigated numerically. Results of a parametric study have been presented in this paper.As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected.Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT).Simulations were carried out with Computational Fluids...
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Bezzałogowe środki latające (BSL) w układzie czterowirnikowego helikoptera
PublicationRozwój układów sterowania, kamer pracujących w świetle widzialnym oraz w podczerwieni doprowadził do wzrostu znaczenia bezpilotowych środków latających. Bezpilotowe środki latające wykorzystywane są do realizacji celów zarówno wojskowych, jak i cywilnych. Podstawowymi zaletami bezpilotowych środków latających są: małe wymiary, duża mobilność, niskie koszty wytworzenia i eksploatacji. Użytkowanie bezpilotowych środków latających...
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MODELOWANIE TURBINY WIATROWEJ Z DWOMA PRZECIWBIEŻNIE OBRACAJĄCYMI SIĘ WIRNIKAMI
PublicationW artykule przedstawiono sposoby modelowania dwuwirnikowej turbiny wiatrowej z wykorzystaniem technik Obliczeniowej Mechaniki Płynów. Omówiono uproszczone metody modelowania Actuator Disc i Actuator Line Method oraz aspekty związane z dokładnym odwzorowaniem turbiny na siatce obliczeniowej. Zaprezentowano przykładowe wyniki obliczeń turbiny dwuwirnikowej złożonej z wirników NREL o mocy nominalnej 5 MW każdy. Do wykonania badań...
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Broken Rotor Symptons in the Sensorless Control of Induction Machine
PublicationInverter fed sensorless controlled variable speed drives with induction machine are widely used in the industry applications, also in wind power generation and electric vehicles. On-line self diagnostic systems implementation is needed for early stage fault detection and avoiding a critical fault. Diagnostic algorithms in modern DSP-based controllers can operate simultaneously with control system functions. In the closed-loop controlled...
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Rotational state-changing collisions of C2H− and C2N− anions with He under interstellar and cold ion trap conditions: A computational comparison
PublicationWe present an extensive range of quantum calculations for the state-changing rotational dynamics involving two simple molecular anions that are expected to play some role in the evolutionary analysis of chemical networks in the interstellar environments, C2H− (X1Σ+) and C2N− (X3Σ−), but for which inelastic rates are only known for C2H−. The same systems are also of direct interest in modeling selective photo-detachment experiments...
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Research and applications of active bearings: A state-of-the-art review
PublicationControllable/active bearings are mainly associated with active magnetic bearings (AMBs), whereas active bearing control is also found in many types of bearings, e.g. fluid, gas and hybrid bearings. The article presents a review of the literature describing the structure and results of studies of active bearings. Active control brings a number of benefits resulting in the fact that their use as a support for rotors becomes increasingly...
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Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 2/2
PublicationThe process of conversion of wind kinetic energy into electricity in innovative wind power plant emits practically no harmful substances into the environment. However, the production stage of its components requires a lot of energy and materials. The biggest problem during production plan-ning process of an innovative wind power plant is selection of materials and technologies and, consequently, the waste generated at this stage....
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Comparative Analysis of Unmanned Aerial Vehicles Used in Photogrammetric Surveys
PublicationThere are many manufacturers on the market offering various types of Unmanned Aerial Vehicles (UAV). The multitude of drones available on the market means that the choice of a UAV for a specific application appears to be a decision problem to be solved. The aim of this article is a comparative analysis of drones used in photogrammetric surveys. The criteria for evaluating the UAVs were: availability and product support, payload...
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Axial-Flux Permanent-Magnet Dual-Rotor Generator for a Counter-Rotating Wind Turbine
PublicationCoaxial counter-rotating propellers have been widely applied in ships and helicopters for improving the propulsion efficiency and offsetting system reactive torques. Lately, the counter-rotating concept has been introduced into the wind turbine design. Distributed wind power generation systems often require a novel approach in generator design. In this paper, prototype development of axial-flux generator with a counter-rotating...
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A Highly Sensitive Planar Microwave Sensor for Detecting Direction and Angle of Rotation
PublicationThis article presents a technique based on a modified complementary split-ring resonator (CSRR) to detect angular displacement and direction of rotation with high resolution and sensitivity over a wide dynamic range. The proposed microwave planar sensor takes advantage of the asymmetry of the sensor geometry and measures the angle of rotation in terms of the change in the relative phase of the reflection coefficients. The sensor...
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Modeling by finite element methods of impact of erosion on frequency of normal modes of L-0 blade
PublicationAfter some time of exploitation steam turbine rotors blades in energetic industry they are being eroded and also their frequency of normal modes is changed. Those changes can cause to unwanted shift of blades normal mode frequencies. It is necessary to find quick method of rating changes of frequency in connection of mass loss due erosion. The evaluation of this dependence was made by finite element modeling method using HyperWorks...
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RANS-based design optimization of dual-rotor wind turbines
PublicationPurpose An improvement in the energy efficiency of wind turbines can be achieved using dual rotors. Because of complex flow physics, the design of dual-rotor wind turbines (DRWTs) requires repetitive evaluations of computationally expensive partial differential equation (PDE) simulation models. Approaches for solving design optimization of DRWTs constrained by PDE simulations are investigated. The purpose of this study is to determine...
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Application of sliding switching functions in backstepping based speed observer of induction machine
PublicationThe paper presents an analysis of the speed observer which is based on the backstepping and sliding mode approach. The speed observer structure is based on the extended mathematical model of an induction machine. The observer structure is based on the measured phase stator currents and transformed to ( αβ ) coordinate system. The stator voltage vector components are treated as known values. Additionally, such an observer structure...
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Stability Enhancement of Grid-Connected Wind Power Generation System Using PSS, SFCL and STATCOM
PublicationThe stability related issues may occur in a power system due to disturbances in generating or loading conditions, especially in the presence of distributed generation (DG) based on renewable energy resources (RERs). This paper proposes a novel strategy for the stability enhancement of a wind power generation system (WPGS) by using a combination of three devices, namely, a power system stabilizer (PSS), resistive superconductor...