• Title/Summary/Keyword: Rotor performance

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Speed-sensorless Induction Motor Control System using the Rotor Flux Error (회전자 자속 오차를 이용한 센서리스 유도전동기 제어 시스템)

  • Jeong Gang-Youl
    • Proceedings of the KIPE Conference
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    • 2003.11a
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    • pp.123-126
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    • 2003
  • This paper proposes a speed-sensorless induction motor control system using the rotor flux error. The rotor flux observer uses the reduced- dimensional state estimator technique instead of directly measuring the rotor flux. The estimated rotor speed is obtained directly from the electrical frequency, the slip frequency, and the rotor speed compensation with the estimated q-axis rotor flux. To precisely estimate the rotor flux, the actual value of the stator resistance, whose actual variation is reflected, is derived. For fast calculation and improved performance of the proposed algorithm, all control functions are implemented in software using a digital signal processor (DSP) with its environmental circuits. Also, it is shown through experimental results that the proposed system gives good performance for the speed-sensorless induction motor control.

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An Experimental Study of the Effect of Regeneration Area Ratio on the Performance of Small-Sized Dehumidification Rotor for Residential Usage (재생 면적비가 가정용 소형 제습로터의 성능에 미치는 영향에 관한 실험적 연구)

  • Kim, Nae-Hyun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.5
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    • pp.277-282
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    • 2015
  • During hot and humid weather, air-conditioners consume a large amount of electricity due to the large amount of latent heat. Simultaneous usage of a dehumidifier may reduce latent heat and reduce electricity consumption. In this study, dehumidification performance was measured for a small-sized dehumidification rotor made of inorganic fiber impregnated with metallic silicate within a constant temperature and humidity chamber. Regeneration to dehumidification depends on ratio, rotor speed, room temperature, regeneration temperature, room relative humidity and frontal velocity to the rotor. Results demonstrate an optimum area ratio (1/2), rotor speed (1.0 rpm), and regeneration temperature ($100^{\circ}C$) to achieve a dehumidification rate of 0.0581 kg/s. As the area ratio increases, the optimum rotation speed and the optimum regeneration temperature also increase. Above the optimum rotor speed, incomplete regeneration reduces dehumidification. Above the optimum regeneration temperature, increased temperature variation between regeneration and dehumidification reduces dehumidification. Dehumidification rate also increases with an increase of relative humidity, dehumidification temperature and flow velocity into the rotor.

Effect of Axial Spacing between the Components on the Performance of a Counter Rotating Turbine

  • Subbarao, Rayapati;Govardhan, Mukka
    • International Journal of Fluid Machinery and Systems
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    • v.6 no.4
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    • pp.170-176
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    • 2013
  • Counter Rotating Turbine (CRT) is an axial turbine with a nozzle followed by a rotor and another rotor that rotates in the opposite direction of the first one. Axial spacing between blade rows plays major role in its performance. Present work involves computationally studying the performance and flow field of CRT with axial spacing of 10, 30 and 70% for different mass flow rates. The turbine components are modeled for all the three spacing. Velocity, pressure, entropy and Mach number distributions across turbine stage are analyzed. Effect of spacing on losses and performance in case of stage, Rotor1 and Rotor2 are elaborated. Results confirm that an optimum axial spacing between turbine components can be obtained for the improved performance of CRT.

Design and Optimization Study on the Multi Flight Modes Canard Rotor/Wing Aircraft with Development of Sizing Program (사이징 프로그램 개발을 통한 다중 비행 모드 Canard Rotor/Wing 항공기의 형상 최적설계)

  • Kim, Jong-Hwan;Kim, Min-Ji;Lee, Jae-Woo;Lee, Chang-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.2
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    • pp.22-31
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    • 2005
  • A design study was conducted for a new concept aircraft(Canard Rotor/Wing: CRW) that has the capability of dual mode flight, a rotorcraft and a fixed wing mode. The CRW can show a vertical take off/landing and a high speed/efficiency cruise performance simultaneously. It is not surprising to develop a new sizing code for this class of aircraft because conventional sizing codes developed solely for either the rotary wing or the fixed wing aircraft are not adequate to design a dual mode aircraft operated both by the rotary wing through tip jet effux and the fixed wing lift. Thus, a new design code was developed based on the conventional sizing code by adding some features including rotor performance, duct flow, and engine flow analysis, hence could eventually predict the performance of reaction driven rotor, the flight performance and the flight characteristics. The various design parameters were investigated to find their influences on the flight performance then, a small UAV(Unmanned Aircraft Vehicle) of 1500 lbs class was optimally designed to have minimum weight using the developed sizing code.

Effect of Desiccant and Channel Geometries on the Performance of Desiccant Rotor (제습제와 채널이 제습로터 성능에 미치는 영향)

  • Chung, Jae-Dong;Lee, Dae-Young;Yoon, Seok-Mann
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.8
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    • pp.569-576
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    • 2007
  • The desiccant rotor is the most essential component of desiccant cooling system, but one of its drawbacks to spread out is rotor size. To reduce the size of rotor the analysis of rotor performance is crucial. Systematic examination on the effect of desiccant and channel geometries has been conducted based on the numerical program previously developed. Considered parameters related to channel geometries are channel shape and cross section area of channel, and parameters related to desiccant are mass fraction, heat capacity, density, maximum water uptake and separation factor of isotherm. Considerable reduction of rotor size is expected by adjusting the parameters.

A Study of the Conceptual Design of Medium Size Utility Helicopter Rotor System (중형 헬리콥터 로터 시스템 개념설계 연구)

  • Kim, June-Mo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.3 s.22
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    • pp.33-41
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    • 2005
  • This paper describes the conceptual design of medium size helicopter rotor system. Based on assumed design requirements, trade-off study for rotor configuration has been conducted in terms of rotor tip speed, disk loading, blade area, solidity, etc for estimated primary mission gross weight. For the main rotor, four-blade and five-blade rotors are studied with the conventional tail rotor. The performance analysis for baseline configuration is conducted using a helicopter performance analysis program. The analysis shows design results satisfy the design requirements.

A Study on the Improvement of the Rotor Shape for Improving Performance of Small Wind Turbine with Vertical Axis (수직축 소형 풍력터빈 성능 향상을 위한 로터 형상 개선에 대한 연구)

  • Kim, C.J.;Kim, J.U.;Paek, I.S.;Kim, C.J.
    • Journal of Industrial Technology
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    • v.37 no.1
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    • pp.37-40
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    • 2017
  • This study was carried out to improve the performance of a vertical-axis micro wind turbine. It is unique in that it has two identical generators on both sides of the main shaft. Also it has a C shape frame to fix the generators and the main shaft firmly and to provide a connection to a tower. Performance analysis of the wind turbine rotor was performed using Qblade, which is an analysis program for vertical axis wind turbines and freeware. Based on the analysis results, the blade airfoil, the chord length, and the rotor size were modified to improve the performance of the rotor. The modification was found to increase the performance of the wind turbine and to reach the targeted rated power.

Numerical investigation on effects of rotor control strategy and wind data on optimal wind turbine blade shape

  • Yi, Jin-Hak;Yoon, Gil-Lim;Li, Ye
    • Wind and Structures
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    • v.18 no.2
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    • pp.195-213
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    • 2014
  • Recently, the horizontal axis rotor performance optimizer (HARP_Opt) tool was developed in the National Renewable Energy Laboratory, USA. This innovative tool is becoming more popular in the wind turbine industry and in the field of academic research. HARP_Optwas developed on the basis of two fundamental modules, namely, WT_Perf, a performance evaluator computer code using the blade element momentum theory; and a genetic algorithm module, which is used as an optimizer. A pattern search algorithm was more recently incorporated to enhance the optimization capability, especially the calculation time and consistency of the solutions. The blade optimization is an aspect that is highly dependent on experience and requires significant consideration on rotor control strategies, wind data, and generator type. In this study, the effects of rotor control strategies including fixed speed and fixed pitch, variable speed and fixed pitch, fixed speed and variable pitch, and variable speed and variable pitch algorithms on optimal blade shapes and rotor performance are investigated using optimized blade designs. The effects of environmental wind data and the objective functions used for optimization are also quantitatively evaluated using the HARP_Opt tool. Performance indices such as annual energy production, thrust, torque, and roof-flap moment forces are compared.

Turbine Performance Degradation Due to Blade Surface Roughness (블레이드 표면거칠기에 따른 터빈 성능저하)

  • Park, Il-Young;Yun, Yong-Il;Song, Seung-Jin
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.92-98
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    • 2003
  • Turbine blades experience significant surface degradation with service. This paper presents experimental evidence of blade surface roughness reducing turbine efficiency. Performance tests were conducted in a low speed, single-stage axial flow turbine rig with roughened blade surfaces. Sheets of sandpaper with equivalent sandgrain roughnesses of 106 and $400{\mu}m$ were used to roughen the blades. In these tests, effects of roughened stator vanes and rotor blades were separately evaluated. In the fully rough regime ($k_{s}=400{\mu}m$), the experimental results show an 11 percent decrease in normalized efficiency with roughness only on stator vanes ; an 8 percent decrease with roughness only on rotor blades ; and a 19 percent decrease with roughness on both the stator and rotor blades. In the transitionally rough regime ($k_{s}=106{\mu}m$), the trends are similar approximately 4 percent decrease with either roughened stator or roughened rotor and an 8 percent decrease with roughness on both stator and rotor blades. Thus, roughened stator vanes incur more performance penalty than roughened rotor blades.

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Numerical Study on the Aerodynamic Performance of Asymmetric Vertical Folding Rotor Sail (비대칭 수직 접이식 로터세일의 성능 평가에 관한 수치해석 연구)

  • Jung Yoon Park;Janghoon Seo;Dong-Woo Park
    • Journal of the Society of Naval Architects of Korea
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    • v.61 no.2
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    • pp.68-76
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    • 2024
  • The rotor sail is one of the representative devices in eco-friendly wind-assisted propulsion systems that have been practically applied to commercial ships. The present study proposes an asymmetric vertical folding rotor sail (AFRS) designed for small ships, featuring asymmetric geometry along the vertical direction and the function of vertical folding. To evaluate the aerodynamic performance of rotor sail, the drag, lift and lift-to-drag ratio were derived using computational fluid dynamics. The aerodynamic performance of AFRS was compared with that of normal rotor sail with different aspect ratios and spin ratios. The effect of geometric parameters on the aerodynamic performance of AFRS was assessed by varying the asymmetric diameter ratio. The maximum improvement in lift-to-drag ratio for AFRS was approximately 12% in the considered case. Additionally, the resistance is decreased when AFRS is vertically folded without rotating. Throughout the present study, improved aerodynamic and resistance performances for AFRS were confirmed, which will successfully provide additional propulsion to small ships.