• Title/Summary/Keyword: 터빈 깃

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Design and Analysis of a Radial Turbine for Ocean Thermal Energy Conversion (해양온도차발전용 반경류 터빈의 설계 및 해석)

  • Nguyen, Van Hap;Lee, Geun Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.3
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    • pp.207-214
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    • 2015
  • The preliminary design of a radial inflow turbine using R134a as the working fluid at 5 kW of power for application to ocean thermal energy conversion (OTEC) is performed to obtain the trends for the efficiency and geometrical dimensions of the turbine. Using input conditions that included a turbine inlet temperature of $25^{\circ}C$, an outlet static pressure of 4.9 bar, and a mass flow rate of 1.16 kg/s, the results of a mean flow analysis show the major dimensions of the turbine, along with an angular velocity of 12,820 rpm. Based on these results, a three-dimensional turbine model is constructed for a computational fluid dynamics (CFD) analysis. The flow characteristics inside the turbine, including the volute and nozzle, are investigated using the CFD software ANSYS CFX. For a pertinent number of nozzle guide vanes, ranging from 10 to 15, the turbine efficiency was higher than 80%, with the highest efficiency shown by a nozzle with 15 guide vanes.

Design and Performance Analysis of Steam Turbine for Variations of Degree of Reaction (반동도에 따른 증기터빈의 설계 및 성능해석)

  • Shin, Jung-Ha;Lee, Geun-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.12
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    • pp.1391-1398
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    • 2011
  • Design and performance analysis of a steam turbine for variations of degree of reaction were performed by computer simulation. Design parameters such as blade angles, exit areas, and heights of the nozzle and moving blade were represented as functions of the degree of reaction. The main performance factors such as turbine power, diagram efficiency, and axial thrust were also expressed in terms of the degree of reaction. For further information about the design and performance, the blade angles and main performance factors were investigated as functions of the flow coefficient. The turbine power and diagram efficiency reached a maximum value for a given degree of reaction and flow coefficient, and the symmetric shape of the moving blade showed distortion as the degree of reaction was increased.

Off-design performance analysis of radial inflow turbines with or without variable area guide vane (가변안내깃이 존재하거나 없는 구심터빈의 탈설계 성능해석)

  • 한기수;김광호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.6
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    • pp.2171-2180
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    • 1991
  • An analysis model for off-design performance of radial inflow turbines with or without variable area guide vane is developed, where two important factors in loss models, total pressure ratio between variable area guide vane exit and scroll casing inlet and rotor loss coefficient are determined without experimental data. The analysis results show that the predicted trends with or without variable area guide vane are consistent with the experimental observations. The comparison of present method with the well-known NASA off-design performance analysis program shows that the mass flow rate and static efficiency by present analysis are in good agreement with those by the NASA program. Therefore, this method can be used to predict off-design performance of radial inflow turbines with validity of the loss models used by present analysis.

Aerodynamic Design of 10 kW-level HAWT Rotor Blades (10 kW급 수평축 풍력 터빈 로터 블레이드의 공력 설계)

  • Chang, Se-Myong;Lee, Jang-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.10
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    • pp.884-890
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    • 2007
  • The procedure for the aerodynamic design of the rotor blades for 10 kW-level HAWT (horizontal axis wind turbine) has been investigated to be practiced systematically. The approximately optimal shape was designed using an inverse method based on the momentum theory and the blade element method. The configuration was tested in the wind tunnel of the Korea Air Force Academy, and the data was compared with those obtained from the real system manufactured from the present design. From this research, the authors established the systematic technolo for wind turbine blades, and set up the technical procedure which can be extended for the future design of middle and large sized wind turbines.

A Study on the Blade Load Measurement of Partial-admission Turbine Cascade (충동형 터빈 캐스케이드의 깃 하중 측정에 관한 연구)

  • Lim, Dong-Hwa;Jang, Jin-Man;Lee, Eun-Seok;Kim, Jin-Han;Choi, Jong-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.2
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    • pp.143-148
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    • 2007
  • An impulse turbine, which is a main component of a liquid rocket engine, needs to be a small size with light weight and generate large power. Since the impulse turbine is being operated under complicated supersonic conditions, flow analysis and performance prediction largely depend on CFD technique. In order to increase the reliability of the prediction code, however, it often requires an experimental data to compare. In this research a rotating turbine rotor with multiple blades is simulated with a two-dimensional stationary cascade to check the effect of major flow parameters. Mach number is measured at nozzle exit by using a pitot tube and the blade thrust was also measured with a load cell. The measured thrust coefficient and the power are compared well with the designed conditions, which proves the design procedures are properly taken.

Experimental Study on Effects of the Contoured Endwall on the Three-Dimensional Flow in a Turbine Nozzle Guide Vane Cascade (곡면 끝벽을 갖는 터빈 노즐 안내깃 캐스케이드내 3차원 유동장에 관한 실험적 연구)

  • Yun, Won-Nam;Chung, Jin-Taek
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1975-1980
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    • 2004
  • The three-dimensional flow in a turbine nozzle guide vane passage causes large secondary loss through the passage and increased heat transfer on the blade surface. In order to reduce or control these secondary flows, a linear cascade with a contoured endwall configuration was used and changes in the three-dimensional flow field were analyzed and discussed. Measurements of secondary flow velocity and total pressure loss within the passage have been performed by means of five-hole probes. The investigation was carried out at fixed exit Reynolds number of $4.0{\times}10^5$. The objective of this study is to document the development of the three-dimensional flow in a turbine nozzle guide vane cascade with modified endwall. The results show that the development of passage vortex and cross flow in the cascade composed of one flat and one contoured endwalls are affected by the flow acceleration which occurs in contoured endwall side. The overall loss is reduced near the flat endwall rather than contoured endwall.

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Time Domain Prediction and Analysis of Low Frequency Noise from Wind Turbine using Hybrid Computational Aeroacoustics (CAA) Method (복합 전산 공력음향학(CAA) 방법을 이용한 시간영역 풍력터빈 저주파수 소음 예측과 분석)

  • Lee, Gwang-Se;Cheong, Cheolung;Kim, Hyung-Taek;Joo, Won-Ho
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.5
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    • pp.369-376
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    • 2013
  • Using Lowson's acoustic analogy, low frequency noise of a wind turbine (WT) is predicted in time domain and the noise sources contributing to the low frequency noise is analyzed. To compute averaged pressure distribution on blades of the WT as noise source, XFOIL is utilized. The blade source domain is divided into several segments along the span direction to compute force exerted on air surrounding the blade segments, which is used as input for noise prediction. The noise sources are decomposed into three terms of force fluctuation, acceleration and velocity terms and are analyzed to investigate each spectral contribution. Finally, predicted spectra are compared with measured low frequency noise spectrum of a wind turbine in operation. It is found that the force fluctuation component contributes strongly in low frequency range with increasing wind speed.

A Numerical Investigation of External and Internal Heat Transfer in A High Subsonic in Turbine Cascade (고 아음속 터빈 깃 주위의 열유동 및 내부 열전달에 관한 수치해석 연구)

  • Kim, Woo-Jin;Kim, Hyun-Shik;Kwak, Jae-Su;Kim, Hark-Bong
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.18 no.1
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    • pp.33-38
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    • 2010
  • Developments of numerical methods are very important to design and analysis for a high subsonic turbine blade. In general, Analysis by experimental investigation has needed a lot of human resources and required time, indispensably, and equipments still have a limit to measure in conditions of high temperature. Rapid technological developments of CPU and integration level of memory make it possible to advance computation with almost exactly simulation so, recent developments of numerical methods are in spotlight. In the present study, the panel method, which is well-known as relatively simplified numerical method, and 2-dimensional ordinary differential Falkner-Skan equation were computed in order to analyze the outer flow, and FVM-based solid heat transfer equation, was also computed to forecast the temperature distribution of the airfoil and the turbine blade. Unstructured grid was constructed in the turbine blade, which has double cooling holes, in order to analyze the internal heat transfer. Cooling fluid was assumed as fully-developed turbulent flow and that circulated in cooling holes.

Aerodynamic Performance Prediction of Horizontal Axis Wind Turbine by Vortex Lattice Method (와류 격자법에 의한 수평축 풍력터빈의 공기역학적 성능예측)

  • 유능수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1264-1271
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    • 1990
  • The vortex lattice method was adopted to predict the aerodynamic performance of a horizontal axis wind turbine. For this simulation. the rotor blade was divided into many panels both in chordwise and spanwise direction and then replaced by horseshoe vortices. The wake was divided into two parts of near wake and far wake : the near wake was assumed as helical vortex line elements and the far wake was modeled by semi-infinite circular vortex cylinder. The induced velocity components were calculated by the Biot-Savart law. By this way the power coefficient was obtained and represented as a function of the tip speed ratio. The numerical results obtained were compared with those of the other methods and experimental results and showed good agreement with experimental results.

Experimental Study on Effect of the Contoured Endwall on the Three-Dimensional Flow in a Turbine Nozzle Guide Vane Cascade (끝벽의 형상이 터빈 노즐안내깃 캐스케이드내 3차원 유동에 미치는 영향에 관한 연구)

  • Yun, Won-Nam;Chung, Jin-Taek
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.514-519
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    • 2003
  • The objective of this study is to document the secondary flow and the total pressure loss distribution in the contoured endwall installed linear turbine nozzle guide vane cascade passage and to propose an appropriate contraction ratio of the contoured endwall which shows the best loss reduction among the simulated cases. In this study, three different contraction ratio of contoured endwalls have been tested. This study was performed by experimental method and when the contoured endwall has the contraction ratio of 0.17 on exit height the results showed the best loss reduction.

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