• Title/Summary/Keyword: 원심 압축기

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Characteristics of Rotating Stall in a Centrifugal Compressor with Vaned Diffuser (원심압축기 베인 디퓨저에서의 선회실속 특성)

  • Lee, Du-Yeol;Kang, Chang-Sik;Shin, You-Hwan;Kim, Kwang-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.5 no.1 s.14
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    • pp.42-48
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    • 2002
  • In this study, the instability of a centrifugal compressor with vaned diffuser was investigated. During unstable operation of the test compressor, pressure fluctuations at different diffuser radius ratios were measured by using high frequency pressure transducers. Two different types of stall, mild and deep stalls, were observed alternately and irregularly at some flow rates where the compressor performance was steeply deteriorated. In this transient zone, the size of rotating stall cell was estimated through the wavelet transform analysis. It was about 45 percents of rotor circumferential space at 300 rpm and not dependent on flow rate.

Characteristics of Rotating Stall in a Centrifugal Compressor with Vaned Diffuser (원심압축기 베인 디퓨저에서의 선회실속 특성)

  • Lee, Du-Yeol;Kang, Chang-Sik;Shin, You-Hwan;Kim, Kwang-Ho
    • 유체기계공업학회:학술대회논문집
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    • 2001.11a
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    • pp.99-105
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    • 2001
  • In this study, the instability of a centrifugal compressor with vaned diffuser was investigated. During unstable operation of the test compressor, pressure fluctuations at different diffuser radius ratios were measured by using high frequency pressure transducers. Two different types of stall, mild and deep stall, were observed alternately and irregularly at some flow rate where the compressor performance was steeply deteriorated. In this transient zone, the size of rotating stall cell was estimated through the Wavelet transform analysis. It was about 45 percents of rotor circumferential space at 3000 rpm and not dependent on flow rate.

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Flow Analysis of Centrifugal Compressor Using Quasi-Three-Dimensional Analysis (원심압축기의 유동해석을 위한 준삼차원 해석기법)

  • Ahn, S. J.;Oh, H. W.;Kim, K. Y.
    • 유체기계공업학회:학술대회논문집
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    • 2001.11a
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    • pp.106-112
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    • 2001
  • This paper presents analysis of the flows through three different types of radial compressor impeller by using quasi-three-dimensional analysis method. The method obtains two-dimensional solution for velocity distribution on meridional plane, and then calculates approximately the static pressure distributions on blade surfaces. Finite difference method is used for the solutions of governing equations. The compressors have low level compression-ratio and 12 straight radial blades with no sweepback. The results are compared with experimental data and the results of inviscid analysis with finite element method. It can be concluded that the agreement is good for the cases where viscous effects are not dominant.

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Dynamic Characteristics of a High Speed Centrifugal Compressor using Foil Bearings (포일베어링을 사용한 고속 원심압축기의 동특성)

  • Kwon, Kye-Si;Ji, Yoo-Chul;Lee, Sang-Wook;Choi, Moon-Chang
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1450-1454
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    • 2000
  • In order to understand dynamic characteristics of centrifugal compressor supported foil bearing, of which normal operating speed is about 20,000 ${\sim}$ 50,000 rpm, the rotor whirl is measured using gap sensors. Not only critical speeds of rotor system but also stability of rotor whirl, which are main concerns of the turbo compressor system, are measured using gap sensors by varying the rotating speed the rotor. The stiffness characteristics of bearing system is shown to be almost invariant according to speed variation by the measurement of eccentricity. In addition, from the directional power spectral density function of the measured vibration signal, the isotropy stiffness characteristics of foil bearing system is discussed.

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NUMERICAL SIMULATION ON A VOLUTE OF STRAIGHT CONICAL DUCT TYPE BY MULTI-BLOCK GRID (다중 블록 격자를 이용한 원뿔 직관 모양의 벌류트 유동의 수치해석)

  • Bae, H.;Kang, H.G.;Yoon, J.S.;Park, K.C.;Chang, K.S.
    • Journal of computational fluids engineering
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    • v.11 no.1 s.32
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    • pp.1-7
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    • 2006
  • Numerical investigation of a centrifugal compressor volute having a modified straight conical duct hill been made. Three-dimensional Reynolds-Averaged Navier-Stokes equations with $k-{\varepsilon}$ turbulence equation are solved To avoid coordinate singularity at the central axis of the duct, multi-block H-type grid is generated on the circular cross-sections of the volute and stretched toward the solid wall boundary. We obtained numerical results with three different mass flow rates at the volute inlet, namely, with the inlet conditions that give small, medium and large mass flow rates at the outlet of the conical duct. Agreement with the experimental results is observed.

The effect of pinched diffuser on aerodynamic performance in a centrifugal compressor (Pinch 디퓨저를 사용한 원심압축기의 공력성능 연구)

  • O, Jong-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.11
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    • pp.3639-3648
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    • 1996
  • The effect of 15% pinched diffuser in a centrifugal air compressor with a cascade airfoil diffuser on the aerodynamic performance is investigated using a numerical approach. The commercial CFD code for three-dimensional, turbulent, compressible flow fields is executed for various mass flow rates at a design speed which can be obtained as long as the calculation succeeds. The pinched diffuser is found to help improve the instability of flow within vaneless diffuser space, especially the reverse flow near shroud, and to change both stall/surge line and choking line to increase the surge margin. It is also found to generate more favorable increase of static pressure in diffuser region, and to increase the resulting pressure ratio and efficiency.

A Design Study of Aerodynamic Noise Reduction In Centrifugal Compressor Part II . Low-noise Optimization Design (원심압축기의 공력소음 저감에 관한 설계연구 Part II : 저소음 최적설계)

  • 선효성;이수갑
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.10
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    • pp.939-944
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    • 2004
  • The numerical methods including the performance analysis and the noise prediction of the centrifugal compressor impeller are coupled with the optimization design skill, which consists of response surface method, statistical approach, and genetic algorithm. The flow-field Inside of a centrifugal compressor is obtained numerically by solving Wavier-Stokes equations. and then the propagating noise is estimated from the distributed surface pressure by using Ffowcs Williams-Hawkings formulation. The quadratic response surface model with D-optimal 3-level factorial experimental design points is constructed to optimize the impeller geometry for the advanced centrifugal compressor. The statistical analysis shows that the quadratic model exhibits a reasonable fitting quality resulting in the impeller blade design with high performance and low far-field noise level. The influences of selected design variables, objective functions, and constraints on the impeller performance and the impeller noise are also examined as a result of the optimization process.

A Parametric Study of Aerodynamic Noise in Centrifugal Compresso (원심압축기의 공력소음에 관한 파라미터 연구)

  • Sun, Hyosung;Lee, Soogab;Lee, Jungeun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.2 s.95
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    • pp.129-134
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    • 2005
  • This paper describes the influence of geometric parameters on the noise generation from a centrifugal compressor. From the analysis of noise measurements, it is observed that Blade Passing Frequency noise related to the rotating impeller is more important, and it is focused on the comparison of this discrete frequency noise according to the shape change. Navier-Stokes solver is used to simulate the flow-field of the impeller and the vaned diffuser, and time-dependent pressure data are calculated and Fourier-transformed to perform the near-field noise prediction. The effects of various geometry design variables such as the gap between the impeller and the diffuser, impeller shape variations on the near-field noise distribution are investigated.

Flow-field Analysis and Noise Prediction of Centrifugal Compressor (원심압축기 유동해석 및 소음예측에 관한 연구)

  • 선효성;신인환;이수갑
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1005-1009
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    • 2002
  • The objective of this research is to suggest the noise prediction method of the centrifugal compressor. It is focused on the Blade Passing Frequency (BPF) component which is regarded as the main part of the rotating impeller noise. Euler solver is used to simulate the flow-field of the centrifugal compressor and time-dependent pressure data are calculated to perform the near-field noise prediction by Ffowcs Williams-Hawkings (FW-H) formulation. Indirect Boundary Element Method (IBEM) is applied to consider the noise propagation effect. Pressure fluctuations of the inlet and the outlet in the centrifugal compressor impeller are presented and Sound Pressure Level (SPL) prediction results are compared with the experimental data.

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Numerical Calculation of Flows through Impeller of Centrifugal Compressors by Streamline Curvature Method (유선곡률법에 의한 원심압축기 회전차 내부유동의 수치해석)

  • Kang, S.H.;Shin, Y.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.1 no.1
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    • pp.87-96
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    • 1989
  • Flows through impellers of centrifugal compressors are calculated by a streamline curvature method. A method for the exit boundary condition is suggested in the present paper. Flow angles are assumed to be deviated from the blade angle parabolically. The maximum deviation is adjusted for the whole angular momentum to balance with the empirically estimated value by using Stanitz' slip-factor. The present method is verified to reasonably simulate flows through the impeller, when the 3-dimensionality of the flow is not strong. It is also shown that the method can be applied for the design of the splitter in the impeller.

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