• Title/Summary/Keyword: Axial-Flow Turbine

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Cycle Analysis and Experiment for a Small-Scale Organic Rankine Cycle Using a Partially Admitted Axial Turbine (부분분사 축류형 터빈을 이용한 소규모 유기랭킨 사이클의 실험 및 예측에 관한 연구)

  • Cho, Soo-Yong;Cho, Chong-Hyun
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.5
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    • pp.33-41
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    • 2015
  • Organic Rankine cycle (ORC) has been used to generate electrical or mechanical power from low-grade thermal energy. Usually, this thermal energy is not supplied continuously at the constant thermal energy level. In order to optimally utilize fluctuating thermal energy, an axial-type turbine was applied to the expander of ORC and two supersonic nozzle were used to control the mass flow rate. Experiment was conducted with various turbine inlet temperatures (TIT) with the partial admission rate of 16.7 %. The tip diameter of rotor was to be 80 mm. In the cycle analysis, the output power of ORC was predicted with considering the load dissipating the output power produced from the ORC as well as the turbine efficiency. The predicted results showed the same trend as the experimental results, and the experimental results showed that the system efficiency of 2 % was obtained at the TIT of $100^{\circ}C$.

A Numerical Analysis on the Nozzle-Rotor of a 3-D Supersonic Turbine (3차원 초음속 터빈의 노즐-로터 상호작용에 관한 수치적 연구)

  • Yun Won-Kun;Shin Bong-Gun;Kim Kui-Soon;Kim Jin-Han;Jeong Eun-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.413-422
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    • 2005
  • In this paper, numerical results for 3-D supersonic turbine flow have been firstly compared with the experimental results to verify results computed by $Fine^{TM}/Turbo$. It was found that $Fine^{TM}/Turbo$ can accurately predict flow characteristics within supersonic turbine. Next, an grid system for 3D turbine flow was optimized selected through grid independency test. Finally the effect of axial gap between rotor and nozzle and chamfer angle of blade edge on the flow characteristics within 3-D supersonic turbine was analyzed with Frozen Rotor method.

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A Numerical Analysis of Flow Characteristics in a Heat Recovery Steam Generator with the Change of Inlet Flow Conditions (배열회수보일러(HRSG)의 입구유동 경계조건에 따른 유동특성 변화에 관한 연구)

  • Kim, Tae-Kwon;Lee, Boo-Yoon;Ha, Ji-Soo
    • Journal of the Korean Institute of Gas
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    • v.15 no.3
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    • pp.53-57
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    • 2011
  • The present study has been carried out to analyze the flow characteristics of a heat recovery steam generator with the change of inlet flow conditions by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. The computational flow analysis result of gas turbine exit shows that the maximum axial velocity appears near circular duct wall and the maximum turbulent kinetic energy and dissipation rate exist relatively higher gradient region of axial velocity. The comparison of flow analysis will be executed with change of inlet turbulent flow condition. The first case is using the inlet turbulent properties from the result of computational analysis of gas turbine exit flow, and the second case is using the assumed turbulent intensity with the magnitude proportional to the velocity magnitude and length scale. The computational results of flow characteristics for two cases show great difference especially in the velocity field and turbulent properties. The main conclusion of the present study is that the flow inlet condition of HRSG should be included the turbulent properties for the accurate computational result of flow analysis.

Large Eddy Simulation of an Isothermal Swirling Flow in a Model Gas Turbine Combustor (모델 가스터빈 연소기에서 등온 선회유동의 대 와동 모사)

  • Hwang, Chul-Hong;Lee, Chang-Eon
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.462-468
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    • 2004
  • Large eddy simulation(LES) methodology used to model isothermal non-swirling and swirling flows in a model gas turbine combustor. The LES solver was implemented on parallel computer consisting 16 processors. To verify the capability of LES code and characterize swirling flow, the results was compared with that of Reynolds Averaged Navier-Stokes(RANS) using k -$\epsilon$ model as well as experimental data. The results showed that the LES and RANS well predicted the mean velocity field of a non-swirling flow. Specially, the LES showed a very excellent prediction performance for the corner recirculation zone. In swirling flow, comparing with the results obtained by RANS, LES showed a better performance in predicting the mean axial and azimuthal velocities, and the central recirculation zone. Finally, unsteady phenomena of turbulent flow was examined with LES methodology.

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A Study on the Flow characteristics of Wells Turbine for Wave Power Conversion by Various Flap Shape (파력발전용 웰즈터빈의 Flap형상변화에 따른 유동 특성에 관한 연구)

  • Kim, Dong-Kyun;Choi, Gab-Song;Kim, Jeong-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.26 no.2
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    • pp.1-7
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    • 2006
  • A numerical investigation was performed to determine the effect of airfoil on the optimum flap height using NACA0015 Wells turbine. The five double flaps which have 0.5% difference were selected. A Navier-Stokes code, CFX-TASCflow, was used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the three dimension numerical grid is based upon that of an experimental test rig. This paper tries to disign the double flap of Wells turbine with the numerical analysis.

A Numerical Study on a Supersonic Turbine Performance Characteristics with Different Nozzle-Rotor Axial Gap Spacings (노즐-로터 축간극 거리에 따른 초음속 터빈 내의 성능특성에 대한 수치적 연구)

  • Jeong, Sooin;Choi, Byoung-ik;Kim, Kuisoon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.3
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    • pp.29-38
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    • 2015
  • In this study, 3-dimensional URANS simulation was performed to analyze the effect of the nozzle-rotor axial gap spacing of a supersonic impulse turbine on turbine performance. The computations were conducted for four different axial gap cases corresponding to about 6%, 10%, 20% and 30% of the blade height, respectively. The results show a good agreement with previous studies and the turbine efficiency decreases drastically in certain range. It is examined that the turbine performance characteristics could change depending on the influence of leading edge shock to the nozzle outlet. It is also found that the entropy rise distributions along the span differ from each other.

Design Strategies for Multi-Stage Axial Turbines (다단 축류터빈 공력설계 및 공력성능 향상기법)

  • Kang, Young-Seok;Rhee, DongHo;Cha, BongJun;Yang, SooSeok
    • The KSFM Journal of Fluid Machinery
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    • v.17 no.5
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    • pp.78-82
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    • 2014
  • This paper describes a brief aerodynamic design procedure of multi-stage axial turbine. The design procedure was established including one dimensional scratch design, through flow analysis with empirical correlations, two dimensional airfoil design and three dimensional airfoil stacking. Detailed aerodynamic performance assessment was done with full three dimensional CFD method at the design and off design conditions to construct turbine performance map. With the present method, aerodynamic design procedure of 1st and 2nd stages of high pressure turbine for 10,000lbf class turbofan engine was introduced.

Flow Characteristics about Industrial Agitators Impeller Shape by CFD (전산유체역학을 이용한 산업용교반기의 Impeller형상에 따른 유동특성)

  • Kim, D.K.;Bae, S.T.;Lee, C.J.;Park, J.H.;Kim, O.K.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.321-322
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    • 2006
  • Industrial agitators are used in various industrial fields where they are necessary to intimately mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial agitators are not systematically investigated. The present study alms for clarify unsteady flow characteristics induced by various impellers in a tank. Impellers are pitched blade turbine(PBT) types, Screw type and Rushton turbine type. In this study flow characteristics of the impeller using CFD. The rotating speed of impellers fixed about 100RPM. These three types of Impeller show that typical flow characteristics of axial turbine and suitable for mixing powder

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Numerical Analysis on Effects of the Contoured Endwall on the Three-dimensional Flow Characteristics in a Turbine (끝벽의 형상이 터빈 캐스케이드내 3차원 유동특성에 미치는 영향에 관한 전산해석)

  • Kim, Dae-yu;Chung, Tin-Taek
    • 유체기계공업학회:학술대회논문집
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    • 2002.12a
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    • pp.284-289
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    • 2002
  • The objective of this study is to document the secondary flow and the total pressure loss distribution in the contoured endwall installed linear turbine cascade passage and to propose an appropriate height of the contoured endwall which shows the best loss reduction among the simulated contoured endwall. In this study, three different contoured endwalls have been tested which have different height. This study was performed by numerical method and the result showed the contoured endwall which has the height of $5\%$ of the axial chord showed the best loss reduction rate.

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EFFECTS OF COMPUTATIONAL GRIDS ON NUMERICAL SIMULATION OF TRANSONIC TURBINE CASCADE FLOWFIELDS (천음속 터빈 익렬유동의 수치해석에서의 계산격자점 영향)

  • Chung H.T.;Jung H.N.
    • Journal of computational fluids engineering
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    • v.10 no.2
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    • pp.15-20
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    • 2005
  • Numerical investigations have been performed to examine the effects of the computational grids on the prediction of the flow characteristics inside the turbine cascades. Three kinds of grid system based on H-type grid are applied to the high-turning transonic turbine rotor blades and comparisons with the experimental data and the numerical results of each grid structure have been done. In addition, the grid sensitivity on the estimation of the blade performances has been investigated.