• Title/Summary/Keyword: Axial Gap

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An Experimental Study of 3-D Axial Type Turbine Performance with Various Axial Gaps between the Rotor and Stator (축류형 터빈에서 정${\cdot}$동익 축방향 거리의 변화에 대한 실험적 연구)

  • Kim Jong-Ho;Kim Eun-Jong;Cho Soo-Yong
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.541-544
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    • 2002
  • The turbine performance test of an axial-type turbine is carried out with various axial gap distances between the stator and rotor. The turbine is operated at the low pressure and speed, and the degree of reaction is 0.373 at the mean radius. The axial-type turbine consists of ons-stage and 3-dimensional blades. The chord length of rotor is 28.2mm and mean diameter of turbine is 257.56mm. The power of turbo-blower for input power is 30kW and mass flow rate is $340m^3/min\;at\;290mmAq$ static-pressure. The RPM and output power are controlled by a dynamometer connected directly to the turbine shaft. The axial gap distances are changed from a quarter to two times of stator axial chord length, and performance curves are obtained with 7 different axial gaps. The efficiency is dropped about $5{\%}$ of its highest value due to the variation of axial gap on the same non-dimensional mass flow rate and RPM, and experimental results show that the optimum axial gap is 1.0-1.5Cx.

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Optimal Performance Characteristic of Axial Flux Motor by Controlling Air Gap (공극 제어에 의한 Axial Flux Motor의 최적 운전 특성)

  • 오성철
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.11
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    • pp.535-540
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    • 2003
  • Since axial flux motor has an advantage over more conventional radial flux type motor such as high power density, it can be used as a power train for hybrid electric vehicle and electric vehicle. Also operating range can be extended and efficiency can be improved by changing air gap. Optimal operating air gap is estimated based on the measured efficiency at different air gap. Motor model is developed based on estimated optimal air gap and efficiency. Motor/controller performance is analyzed through simulation. Possible application area of axial flux motor was explored through simulation.

High Speed Axial-gap BLDC Mtor Design (고속용 Axial-gap BLDC Motor 설계)

  • Kim, Young-Kwan;Park, Jin-Soo
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.116-118
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    • 1998
  • This paper describes a basic structure, analysis of characteristics and test method for high speed axial-gap BLDC motor. The newly designed axial-gap BLDC motor has 2-stator disks with 3-rotor disks and is easy to increase power capacity by increasing the numbers of stator/rotor disks. For high speed operating, the rotor is composed of light and strong strength material and has several separated magnets to reduce stress concentraction by centrifugal force.

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A Study of the One-Stage Axial Turbine Performance with Various Axial Gap Distances between the Stator and Rotor (정.동익 축방향 간격에 따른 단단 축류터빈의 성능시험에 관한 연구)

  • Kim, Dong-Sik;Cho, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.4
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    • pp.99-105
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    • 2002
  • The performance test of an axial-type turbine is carried out with various axial gap distances between the stator and rotor. The turbine is operated at the low pressure and speed, and the degree of reaction is 0.373 at the mean radius. The axial-type turbine consists of ons-stage and 3-dimensional blades. The chord length of rotor is 28.2mm and mean diameter of turbine is 257.56mm. The power of turbo-blower for input power is 30kW and mass flow rate is $340m^3$/min at 290mmAq static-pressure. The RPM and output power are controlled by a dynamometer connected directly to the turbine shaft. The axial gap distances are changed from a quarter to three times of stator axial chord length, and performance curves are obtained with 9 different axial gaps. The efficiency varies about 8% of its peak value due to the variation of axial gap on the same non-dimensional mass flow rate and RPM, and experimental results show that the optimum axial gap is 1.6-1.9Cx.

A Simplified Method to Calculate the EMF Characteristics of Multi-disk Axial-gap PM Motor using 2-D & 3-D FEM

  • Kim, Young-Kwan;Lee, Ju
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.3
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    • pp.34-39
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    • 2008
  • The purpose of this paper is characteristic analysis of multi-disk axial-gap pm motor for turbo compressor. The axial-gap permanent magnet motor has shown a growing interest in high-speed application for its high-efficiency, compact size and low vibration characteristics due to core-less structure. To achieve high-power, the axial-gap PM motor has multi-disk structure of stator and rotor disk. Because of its complicated magnetic flux path, it is not easy to calculate a dynamic characteristics using finite element analysis. In this paper, the simplified 2-D unfolded model to predict EMF characteristic is presented. To verify thesuggested 2-D unfolded model analysis of back-EMF characteristic was calculated and compared 3-D finite element. Finally the proposed method is verified by experimental results and shows good agreement with test results.

A Study of the Characteristics on the Vacuum Interrupter with Axial Magnetic Field Type using 3 Dimension Finite Element Analysis (3차원 유한요소해석을 이용한 종자게형 진공 인터럽터의 특성고찰)

  • 하덕용;강형부
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.5
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    • pp.460-467
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    • 2002
  • This paper deals with the distribution characteristics of the current density and axial magnetic flux density on the vacuum interrupter with axial magnetic field type using 3 dimension finite element analysis. An axial magnetic field parallel to the current flow in the arc column can improve the current breaking capacity of vacuum interrupter by affecting the arc mode. The axial magnetic flux density on the contact electrode surface is analyzed by inputting external current as a function of the transient time for sine half wave. And it also is analyzed within the gap distance of the contact electrode. The peak value of current but is decreased with the descending current on the contact electrode surface and within the gap distance of the contact electrode. The residual magnetic field is generated on the contact electrode surface and within the gap distance in the instant of zero current, which is due to the influence of eddy currents. The phase shift due to eddy currents, defined as time difference between the maximum value of current and axial magnetic field, is about 1ms in the center point of gap distance.

Numerical Study of The Nozzle-Rotor Axial Gap Effect on the Supersonic Turbine Performance (충동형 초음속 터빈의 노즐-로터 축간극에 따른 성능변화 연구)

  • Jeong, Soo-In;Kim, Kui-Soon;Jeong, Eun-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.160-163
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    • 2010
  • We performed three-dimensional CFD analysis to investigate the effect of the nozzle-rotor axial gap of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for five axial gaps using flow analysis program, $FLUENT^{TM}$. The results show that the axial gap between nozzle and rotor give the effect on the mass flow rates of tip leakage and the flow angle at the rotor outlet.

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The vibration and noise characteristic analysis of the BLDC Axial-gap type motor by using Finite Element Method (FEM 을 이용한 BLDC Axial-gap type 전동기의 진동과 소음 특성 분석)

  • Lee, Taeck-Jin;Park, Jun-Hong;Lee, Sang-Ho;Hong, Jung-Pyo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.943-946
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    • 2007
  • The vibration and noise characteristic of the Axial-gap motor for an air conditioner were analyzed. Experimental Modal Analysis was performed to understand the vibration characteristic of the motor. The noise of motor was measured in a dead room. Finite Element Method was performed to find the vibration characteristic of the motor by using ABAQUS program.

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A Study on the Effect of the Contact Electrode Slits in the Vacuum Interrupter with Axial Magnetic Field Type (종자계형 진공 인터럽터에서 접점전극 슬릿의 영향에 관한 연구)

  • 하덕용;강형부;최승길;최경호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.9
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    • pp.822-829
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    • 2002
  • This paper deals with the distribution characteristics of the current density and axial magnetic flux density for each slits made on the contact electrode in the vacuum interrupter with axial magnetic field type using 3-dimension finite element analysis. It has been known that the presence of an axial magnetic field parallel to the current flow in the arc plasma can increase the high current breaking capacity of vacuum interrupter by carrying out the arc plasma from constricted mode to diffusion mode. The axial magnetic field is created of itself by current flow in the segments of coil electrode behind the contact electrode. The analyzed results show that if the slits are made in the contact electrode, they can increase the current density and axial magnetic flux density in the contact electrode surface and at the gap distance, which is due to decrease the effect of eddy currents flowing in the contact electrode. The phase shift due to eddy currents, defined 3s time difference between the maximum value of current and axial magnetic field, is decreased still more by increasing the number of slits made in the contact electrode at the center point of gap distance. These results demonstrate that 3-dimension finite element analysis has a great deal of merits in the development and evaluation of new electrode at the design of vacuum interrupter.

A Development of Eddy Current Sensor System for An Axial-flow type Blood Pump with The Magnetic Bearing (축류형 인공심장의 자기베어링 제어를 위한 와전류 센서 시스템 개발)

  • Ahn, C.B.;Moon, K.C.;Jeong, G.S.;Nam, K.W.;Lee, J.J.;Sun, K.
    • Journal of Biomedical Engineering Research
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    • v.28 no.2
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    • pp.310-315
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    • 2007
  • The axial-flow type blood pump(XVAD) which has been developed in our group consists of mechanical parts (an impeller, a diffuser and a flow straightener) and electrical parts (a motor and a magnetic bearing). The magnetic bearing system fully levitates the impeller to remove mechanical coupling with other parts of the pump with constant gap, which needs non-contact type gap sensing. Conventional gap sensors are too large to be adopted to the implantable axial -flow type blood pump. Thus, in this paper, the compact eddy current type gap sensor system proper for the implantable axial-flow type blood pump was developed and its performance was evaluated in vitro. The developed eddy current type gap sensor system is a transformer type and has a differential probe. Sensor coil(probe) has small dimensions(6 mm diameter, 2 mm thickness) and its optimal inductance was determined as 0.068 mH for the measurement range of $0\sim3mm$. It could be manufactured with 130 turns of the 0.04 mm diameter copper coil. The characteristics of the developed eddy current type gap sensor system was evaluated by in vitro experiment. At experiment, it showed satis(actory performance to apply to the magnetic bearing system of the XVAD. It could measure the gap up to 3mm, but the linearity was decreased at the range of $1.8\sim3.0mm$. Moreover, it showed no difference in different media such as the water and the blood at the temperature range of $35\sim40^{\circ}C$.