• Journal of Advanced Marine Engineering and Technology
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• 제18권3호
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• pp.43-51
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• 1994

The design technique of turbo pumps has been developed due to an increasing demand from related industrial fields. But infant stage of turbomachinery in the domestic industry needs more fundamental design method. Among various types of pumps, centrifugal pump was chosen because of its wide industrial application. It is difficult to decide the correct specification of centrifugal impeller, because of its complex flow analysis at the inlet, passage and outlet. This study is limited on the impeller blade design and its related performance analysis.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.223-226
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• 2009

This paper presents three-dimensional flow analysis for a mixed-flow pump which consists of a rotor and a stator. Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model are discretized by finite volume approximations and solved by the commercial CFD code CFX 11.0. Structured grid system is constructed in the computational domain, which has O-type grids near the blade surfaces and H-type grids in other regions. Validation of the numerical results was performed with experimental data for head coefficients and hydraulic efficiencies at different flow coefficients. This paper shows that the pump characteristics can be predicted effectively by numerical analysis.

• 한국유체기계학회 논문집
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• 제14권1호
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• pp.61-65
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• 2011

A series of water tests of a fuel pump for liquid rocket engines are performed at a room temperature. According to the test results, the head coefficient of the pump follows the conventional similarity rule - unlike this, the pump shows better efficiency with higher rotational speed. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the cavitation performance of the fuel pump is found to be sufficient for the engine operation and is better at the lower flow ratio and higher rotational speed.

• 한국항해항만학회지
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• 제29권6호
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• pp.523-528
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• 2005

장애물이 있는 배관속의 점성유동을 다양한 난류모형을 적용하여 해석하였다. 적용한 난류모형은 k-$\epsilon$, k-$\omega$, Spalart-Allmaras, Reynolds stress 이고, 배관내의 격자는 구조격자(structured grid) 이다. 속도벡터, 압력분포 반복계산(iteration)에 의한 잔류치(residual), 양정(dynamic head) 등을 모사하였다. 4개의 난류모형을 배관유동에 적용하였고 상용 프로그램을 사용하여 해석을 수행하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.589-592
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• 2002

A commercial CFD code is applied to analyze the 3-D viscous flow field within vertical multi-stage centrifugal pump including impeller of centrifugal pump with 6 blades and guide vain with 11 blades. The numerical analysis of vertical multi-stage centrifugal pump is performed by changing flow rate from $8\;to\;26\;m^{3}/h$ at the constant 3500rpm. The characteristics such as total pressure coefficient, total head, water horse power, power efficiency are represented according to flow rate changing. In the future, we will need to perform flow calculation of vertical multi-stage centrifugal pump by considering meridional shape of impeller.

• 가정과삶의질연구
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• 제14권3호
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• pp.109-120
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• 1996

While theories of portfolio selection have been developed very little is known about how individuals actually go about constructing their asset potfolios. This study investigates empirically the characteristics of household's assets and which factor associated with risky and safe asset amount. Data used in this study consisted of 2,164 households and the statistics employed to analyze the data are univariate procedure Logit analysis and OLS. The results of this study were as follows: Among 2,164 households 505 housholds(23.3%) had risky assets. Average risky asset amount is 8,351,500 won and average safe asset amount is 7,086,900 won. Region education and occupation of household head home ownership transfer and other income and total expenditure had significant effects on either and other income and total expenditure had significant effects on either household having risky asset or safe asset. Financial income transfer and other income and total expenditure had significantly p sitive relation with the risky asset amount. Whereas age and the occupation of household head the sense of economic wellbeing earned financial tranfer and other income and total expenditure had significantly positive relation with safe asset amount.

• 설비공학논문집
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• 제13권5호
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• pp.333-340
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• 2001

A centrifugal water chiller using alternative refrigerant R134a have been developed. The prototype was designed to have refrigeration capacity of 300RT. Its compressor employs a single high-speed impeller, airfoil diffuser and collector. Newly developed enhanced tubes were installed in the evaporator and the condenser to reduce the required head for the compressor. Off-design characteristics at various conditions, performance test of the compressor and analysis of the refrigeration cycle were performed. So the probability of use in part load condition was checked and the direction for revision was suggested.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.171-176
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• 2001

The Pump/Motor Selection Program for optimized selection of regional water supply facilities was developed based on a flowchart compiled from basic operational data, total head requirement, initial pump/motor specification selection etc.. This program was developed in Visual Basic. The program accepts, as in the flowchart, operational requirements of pumps and other system requirements and calculates specific speed based on flow rate, total head and na Then the calculated specific speed is used to select pump types and rpm Prior to determining likelihood of cavitation occurring at the calculated NPSH. Power requirement is then calculated for safe operation of pump to assist final pump selection. Test results of the program matches very closely to the design values of Paldang intake pump station(3rd stage) proving that the program can be used as an effective and practical aid for designing new regional water supply systems.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.49-53
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• 2004

LabVIEW is mostly preferred to use in experiment, measurement and control as one of the useful thing in America and Europe. So, We tried performance experiment of a single-stage closed-type centrifugal pump by using the LabVIEW. The pump rpm and the shaft torque are measured by rpm sensor and torque sensor The test pump's maximum rpm, head, kW are 1,750, 13m, and 1.5kW, respectively The casing is made up with transparency acrylic for confirmation the flow patterns. We installed experimental equipment for air water two phase flow. This paper tries to analyze the single-phase flow characteristics through this air water two phase flow experimental apparatus. The performance results of a single-stage closed-type centrifugal pump satisfied reappearance and coincide well with head and coefficients according to the change of rpm.

• 대한지하수환경학회지
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• 제2권1호
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• pp.30-37
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• 1995

조석의 영향을 받는 감조구역의 대수층은 감조 하천의 수위에 따라 지하수 수두의 변화가 예상된다. 지하수 수두가 주기적으로 변화하는 대수층에서 지하수를 이용하거나 구조물을 시공하기 위해서는 지하수 수두의 거동을 고려해야 한다. 감조구역에서 지하수 수두에 영향을 미치는 조석의 진폭과 투수계수 등의 변수에 대해서 수치실험을 수행하였다. 수치실험을 위해 1차원 유한차분 모형을 이용하였다. 우선 수치모형의 안정성을 검토하기 위해 해석해와 비교하였다. 그리고 조석의 진폭과 투수계수가 지하수 수두에 미치는 영향에 대해 고찰하고 이 때 지하수의 수리경사가 존재하는 경우와 없는 경우에 대해 수치실험하였다. 또한 감조구역 내에서 양수를 하는 경우에 지하수 수두의 변화 양상을 고찰하기 위해 수치실험을 수행하였다. 본 논문에서 사용된 변수값을 이용하면 영향권은 약 60 m정도인데 이는 한 파장(equation omitted) 내에서 영향권이 설정된다. 조석의 영향을 받는 대수층과 영향을 받지 앎은 대수층에서 일정한 율로 양수하였다. 영향권 내에서 조석의 영향을 받는 대수층의 수두가 크기 때문에 상대적으로 양정고는 작아져 동력비의 절감을 가져올 수 있음을 알았다 그리고 이들의 결과를 이용하면 감조구역에서 오염원의 추적, 지하수의 효율적인 이용, 구조물을 시공할 때 구조물의 안정성과 안전성을 검토하는데 도움이 될 것이다.