• 설비공학논문집
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• 제14권12호
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• pp.1031-1038
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• 2002

The effects of casing shape on the performance and interaction between the impeller and casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuer and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and three-dimensional time-averaged Wavier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around casing and pressure difference between the inlet and outlet of the compressor are peformed for the circular casing. Comparisons of these results between the experimental and numerical analyses are conducted, and reasonable agreement is obtained.

• 한국유체기계학회 논문집
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• 제10권4호
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• pp.29-38
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• 2007

In this study, flow structure in a two-stage centrifugal compressor for a turbo-chiller with the refrigerant, R134a, was numerically investigated at the design point of the compressor using a commercial code. Flow characteristics in the passages of impeller, diffuser and return channel were analyzed in detail including velocity vector, secondary flow, Mach number and pressure contours in blade spanwise and meridional plane for each stage. The estimation on the one-dimensional output from the preliminary design and three-dimensional shape of the impeller blade and the meridional shape of the return channel were performed through the flow analysis, while some numerical schemes and techniques including Multiple Frames of Reference technique, real gas property data and inlet boundary condition changes, which were used in CFD, were compared with their features. The results will be used as reference data for a new design of 3-D impeller shape to improve R134a compressor performance.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 강연회 및 연구개발 발표회 논문집
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• pp.159-163
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• 1998

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.813-818
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• 2001

The flow characteristics of the vaned diffuser were complicated with geometric shapes. We have studied the effects of various vaned diffuser configurations, such as divergence angles and rectangular and conical cross-section shapes. Numerical analyses are carried out for the diffuser and casing. The pressure recovery coefficient was calculated to estimate the performance of the diffuser, and then compared with the measure data. Results show that the shapes and the divergence angles of the diffuser strongly influence on the performance of the small-size turbo-compressor.

• 한국공작기계학회논문집
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• 제16권3호
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• pp.75-80
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• 2007

It is necessary to analyze the contact phenomena in order to effectively design the machine components with contact surfaces. In general, the contact action is highly nonlinear and irreversible because we cannot predict the contact regions and conditions. Recently, the finite element method is used to analyze the contact problem. In this paper, the contact element method is applied to avoid the mesh refinement and iterative calculation of general contact algorithms. By use of it, the deformation and stress concentration of turbo compressor rotor are computed. It shown that the contact element is convenient analysis and the results are relatively accurate.

• 전자공학회논문지SC
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• 제40권1호
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• pp.45-54
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• 2003

종래의 터보기기는 회전자의 높은 회전속도를 얻기 위하여 증속기어를 사용하였으나 근래에는 초고속 전동기를 적용하여 기계적인 효율 및 시스템의 소형차에 관한 연구가 활발히 진행중이다. 본 논문은 직접구동방식의 터보 압축기를 위한 초고속 영구자석 동기전동기 구동시스템에 관한 논문으로서 150마력 70,000rpm 영구자석 동기전동기 구동시스템을 개발하여 상품에 적용하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.672-677
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• 2001

This study has been conducted to design the high efficiency centrifugal compressor for a HFC-134a. The 2-stage centrifugal compressor consists of inlet guide vanes, two impellers with splitters, a deswirler, a vaneless diffuser and a volute casing. We have designed the high efficiency centrifugal compressor by applying the repeated design procedure including a meanline design, a 3D geometry generation of 1st and 2nd impellers etc. Also, a fluid dynamic calculation of impellers and deswirler have been conducting using a commercial code STAR-CD.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.255-260
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• 1998

A detailed rotordynamic design analysis is performed with a turbo-chiller compressor rotor-bearing system. A pinion is machined into a compressor shaft and the pinion is driven by a bull gear to a rated speed of 14,600 rpm. Utilizing a finite element method each bearing loads are calculated considering various gear loadings as well as the rotor weight itself. A Partial bearing and a 3-Lobe bearing are designed as the compressor impeller out-board bearing and in-board bearing, respectively. Finally a complex rotordynamic analysis of the compressor rotor-bearing system is carried out to evaluate the system whirl natural frequencies, stabilities, and unbalance responses.

• 한국유체기계학회 논문집
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• 제12권5호
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• pp.47-53
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• 2009

A rotordynamic and detailed stability analysis in accordance with API 617 standard were performed with a turbo-compressor, which is one of key rotating machinery in refinery, petroleum, and power plants. The system is composed of rotor shaft, impeller, sleeve hub, balance drum, and coupling hub. The rotor system is supported by tilting pad bearings, which has 5 pads and pad on loading condition. The rotordynamic analysis specified by API 617 includes the critical speed map, mode shape analysis, Campbell diagram, unbalance response analysis, and stability analysis. In particular, the specifications of stability analysis consist of a Level 1 analysis that approximates the destabilizing effects of the labyrinth seals and aerodynamic excitations, and Level 2 analysis that includes a detailed labyrinth seal aerodynamic analysis. The results of a rotordynamic analysis and stability analysis can evaluate the operating compressor health and can be utilized as a guide of its maintenance, repair and trouble solution.

• 항공우주기술
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• 제8권1호
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• pp.98-107
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• 2009

5MW급 발전용 가스터빈을 개발하기 위해 주요 구성품 중의 하나인 압축기의 성능을 시험 평가하고자 하며, 이를 위한 사전 작업으로 압축기 시험 리그의 진동 특성을 분석하여 압축기 운전시 구동 방법에 대한 정보를 확보하였다. 압축기 시험 설비는 입 출구 배관과 시험부 및 구동부로 구성되어 있고, 특히 구동부와 시험부에서 가속도계를 이용하여 진동 특성을 계측하였다. 압축기 주 하우징과 콜렉터, 베어링캐리어, 토크미터, 기어박스, 전동 모터 등에 가속도계를 장착하여 진동 속도 및 주파수 분석을 수행하였다.