• 한국정보통신학회논문지
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• 제6권6호
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• pp.885-890
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• 2002

터보 압축기는 구조적으로 임펠러를 고속회전 시켜야 한다. 범용전동기에 높은 기어비를 가진 기어박스를 이용하여 구현하였는데, 이는 관성 모멘트, 마찰손 및 압축기의 크기를 증가시켰다. 최근에 터보 압축기의 연구는 초고속 동기전동기를 장착하여 기어박스를 제거하여 크기와 마찰손을 최소화하는 방향으로 진행되고 있다. 본 연구에서는 150마력 70,000rpm 직접 구동방식의 터보 압축기를 개발하기 위하여 초고속 동기전동기용 인버터제어기, 공압제어기 및 MMI 기능을 통합한 단일 DSP에 근거한 통합제어기를 구현하였다. 이는 하드웨어적인 부분만 아니라 소프트웨어적인 측면에서도 통합 작업이 필요하였다. 이러한 소프트웨어 및 하드웨어 통합을 통하여 하드웨어적으로는 제어 시스템을 간략화 되었으며, 소프트웨어적으로는 동일한 개발환경에서 각 종 제어기가 구현되고 통합되었다. 이를 개발 및 제작하여 150마력70,000rpm 직접 구동방식의 터보 압축기에 적응하였다

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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• pp.223-232
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• 1998

To investigate the flow inside the centrifugal impeller, computer program which can solve Three-dimensional compressible turbulent flow has been developed. The Navier-Stokes equations were chosen as the governing equation for viscous flow while Euler equations for inviscid case. Time marching method was incorporated with the Flux Difference Splitting method suggested by Roe to capture the steep gradients such as a shock. For high order of accuracy, MUSCL approach was adopted while differentiable limiter to ensure TVD property. For turbulence closure, Baldwin- Lomax model was applied due to its simplicity. To demonstrate the capabilities of present program, several validation problems have been solved and compared with experiments and other available data. From the above calculations generally good agreements were obtained. Finally, the developed code was applied to Eckardt's impeller and the performance prediction was carried out. Some important aspects on boundary condition for successful simulation were discussed and the remedy was also introduced.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1917-1924
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• 2003

This paper proposes a roughing path generation method fer machining impeller with 5-axis machining center. Traditional researches are focus on finishing for machining impeller. To achieve efficient machining, roughing method must be studied. The proposed method consists two steps : One is to select optimal tool size and tool attitude by dividing cutting area into two regions to reduce cutting time. The regions are automatically divided by character point on the geometry of impeller blade. After dividing, the tool of the optimal size is selected for each divided region. The other is avoidance of tool interference. Tool interference in cutting areas is avoided by checking the distance between tool axis vector and ruling line on blade surface or approximated plan between ruling line. Using this method, the cutting time is reduced efficiently.

• 대한기계학회논문집B
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• 제34권9호
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• pp.843-850
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• 2010

본 연구에서는 생활폐기물 관로이송 설비에서 사용되고 있는 터보블로어의 성능향상을 목적으로 하며, 볼류트 케이싱의 확대반경과 폭에 따른 터보블로어의 성능특성을 삼차원 나비어-스톡스 방정식을 통한 수치해석과 실험적인 방법을 적용하여 분석하였다. 수치해석을 통한 압력과 효율특성은 실험값과 잘 일치함을 확인하였다. 수치해석을 이용한 볼류트 케이싱 형상특성 연구를 통하여, 터보블로어의 성능은 임펠러 익간 및 블로어 출구의 압력손실을 줄임으로써 개선됨을 확인하였다. 본 설계변수 분석을 통하여 효율은 약 3%, 압력은 약 2% 개선할 수 있었다. 또한 수치해석 결과를 이용하여 터보블로어의 내부유동장 특성을 비교, 분석하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.801-806
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• 2001

The objective of present study is to find the interaction between volute and impeller of the centrifugal turbomachinery with rectangular cross-sectional volute. Flow measurement were taken in shrouded impeller with 12 backward type blades by using a five-hole pressure probe. The measurements are carried out in 7 flow rate, respectively. Primary function of a centrifugal turbo machinery volute is to serve the flow from the impeller and diffuser to pipe system. For the off-design conditions, Influence of pressure distortion was shown by these measurements. As a result, It has caused the decrease of total efficiency of centrifugal turbomachinery. We have also taken data to design volute by these measurements.

• 한국유체기계학회 논문집
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• 제5권3호
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• pp.25-32
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• 2002

Structural and dynamic analyses of inducer and impeller for an oxidizer turbopump are peformed to investigate the safety level of strength and vibration at a design point. Due to high rotational speed of turbopump, effects of centrifugal forces are carefully considered in the structural analysis. Hydrodynamic pressure is also considered as an external force applied to inducer and impeller blades. A three-dimensional Finite Element Method (FEM) is used for linear and nonlinear structural analyses with modified Newton-Raphson iteration method. After the nonlinear trim solution is obtained from the structural analysis, dynamic characteristics are obtained as a function of rotational speed from the linearized eigenvalue analysis at an equilibrium position. According to the results of numerical analysis, the safety margins of strength and vibration resonances are sufficient enough for safe operation within the requited life cycle.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.408-416
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• 2002

Hydraulic performance of the pump with an inducer was predicted by 3-D Navier-stokes calculation. The evaluated pump was the single-stage centrifugal pump with a separated inducer to pressurize fuel (LCH4) in Turbo-pump system with a specific speed (Ns) of approximately 0.3[rad/s, m3/s, J/kg] and a suction specific speed(s) of 15[rad/s, m3/s, J/kg]. That conventional pump was designed with the combination of 1-D theory and empirical correlation. In this study, preliminary design to select key parameters such as inlet flow coefficient was reviewed by investigating sets of the known design methods to achieve appropriate suction performance, and the performance of newly designed inducer and impeller was compared with the old one, using CFD method. The numerical results showed that the hydraulic efficiency of the new pump was predicted $5.5\%$ higher than that of the conventional one, through design parameter re-selection, configuration improvement and blade loading control

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.54-60
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• 2002

A mini turbo-pump having 44mm diameter impeller for hydraulic power control have been tested to evaluate hydraulic performance and losses. The characteristics of the losses such as mechanical, friction, balancing rib losses were investigated. The investigation revealed that the friction loss is relatively large but the balancing rib loss small. It was found that the hydraulic efficiency of the pump at design point is very low($27\%$) due to low specific speed and large friction losses. A computational fluid dynamics(CFD) method also has been utilized for performance prediction of the mini turbo-pump to compare the computed results with the test data.

• 한국유체기계학회 논문집
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• 제3권4호
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• pp.44-51
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• 2000

The present study has been conducted to design the high efficiency centrifugal compressor for a R134a turbo-chiller. The centrifugal compressor consists of an impeller with splitters, two vaneless diffusers, a low-solidity vaned diffuser and a volute. A cycle analysis program for a turbo-chiller was developed to obtain compressor design parameters and requirements. We have designed the high efficiency centrifugal compressor by applying the repeated design procedure including a meanline design, a 3D geometry generation and fluid dynamic loading calculations.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.63-68
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• 2001

A numerical analysis to predict the flow characteristics in turbo fan for vacuum cleaner has been performed by using CFD. The rotating reference frame method is applied to compute the impeller-diffuser interaction and the characteristics of two models, 460 and 380, are calculated for various rotating speeds and flow rates. The flow in impeller, diffuser and return channel is assumed as steady and compressible. STAR-CD with k- $\epsilon$ turbulence model is used to solve the Navier-Stokes equations. Computed relative velocity, absolute pressure and flow angles are shown and compared with measurement results. The good agreement between the predictions and measurement results confirms the validity of this study.