• 한국소음진동공학회논문집
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• 제21권12호
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• pp.1098-1103
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• 2011

The structural integrity of APR1400 reactor vessel internals has been being assessed referring the US Nuclear Regulatory Commission regulatory guide 1.20, comprehensive vibration assessment program. The program is composed of a vibration and stress analysis, a vibration and stress measurement, and an inspection. This paper covers the vibration and stress analysis on the reactor vessel internals by the pulsation of reactor coolant pump. 3-dimensional models to calculate the hydraulic loads and structural responses were built and the pressure distributions and the structural responses were predicted using ANSYS. This paper presents that APR1400 reactor vessel internals have enough structural integrity against the pulsation of reactor coolant pump as the peak stress of the reactor vessel internals is much lower than the acceptance limit.

• 한국소음진동공학회논문집
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• 제21권11호
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• pp.1029-1035
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• 2011

Pressure pulsation of exciting sources that generally occurs on the piping system connected to the discharge of BFP(boiler feed water pump) in power plants causes wave reflection, wave interference, resonance, standing wave and so on. But if the operating speed of the pump is changed, the state of the noise and vibration can be done because characteristics of the exciting source are changed. This paper is to investigate the cause of the noise and vibration occurring on the piping system when the operating speed of BFP is down in accordance with lowering of the power generation. It is approached to two points of view ; Firstly, it is examined whether the pulsation source impacts on the shell mode vibration that vibrates radially across the cross-section of the pipe. But it doesn't affect the shell mode as much as the resonance occurs. Secondly, to find the relation between the pulsation source and the acoustic mode of the piping system, analysis for the piping system by indirect BEM(boundary element method) is carried out. Therefore it is investigated that the mechanism of the noise and vibration relates with acoustic mode of the piping system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.368-373
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• 2001

A major concern on high-energy centrifugal pump is the potential for interaction of two-phase flow phenomena with mechanical response of the pumping elements. The other concern is the pressure pulsations created from trailing edge of the impeller blade and flow separation and recirculation at partial load in centrifugal pumps. These interactions generating between rotor and casing cause dynamic pulsation on pump and exciting pipeline vibration. The higher severity responses, the more lead to failure of pump and system components. Finally, it cause severe axial vibration of single stage pump due to the hydraulic instability in flow condition below BEP.

• Tribology and Lubricants
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• 제27권6호
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• pp.314-320
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• 2011

Although swash-plate type axial piston pumps have the merits of wide operating conditions and high efficiency, the characteristics of pressure pulsation and flow ripple which result in system noise generation are on-going problems. This research examined the analytic models of the dynamic oil pressure and flow characteristics in the pump. A new mathematical model which considered the pressure behaviors of each cylinder and discharge piping was developed to analyze the pump pressure and flow. This model also considered the leakages in the clearances which many researchers have ignored so far. Using the developed model, numerical calculations were implemented. The results showed that widely used simple model which considered only a single cylinder can not predict actual discrete flow dynamics and that fluid inertia effect has to be considered in the mathematical model. Several critical parameters were discussed such as port volume and discharge resistance on the assumption that the pipe length is not so long. The effect of leakages was studied on the final stage.

• 한국유체기계학회 논문집
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• 제13권5호
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• pp.17-21
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• 2010

A volumetric gear pump is often used in extensive industrial applications to provide both high pressure and sufficiently high flow rate by physical displacement of finite volume of fluid with each revolution. To better understand the unsteady flow characteristics within the pump, numerical simulations were conducted by using moving dynamic meshing (MDM) techniques in commercially available CFD software, FLUENT. The effects of rotor clearance size and rotational speed of rotor on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, was investigated. The results showed that significant reverse flow is developed in the rotor clearance and that its size is one of the most important factors affecting flow characteristics and pressure pulsation.

• 대한기계학회논문집 C: 기술과 교육
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• 제5권2호
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• pp.127-134
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• 2017

원자로내부구조물은 다양한 진동하중조건에서 안전성과 건전성을 유지해야한다. 그러므로 미국원자력규제 위원회는 펌프 압력 맥동에 의한 진동을 포함하여 음향으로 유발되는 진동을 평가하기 위한 규제지침서 1.20을 제시하고 있다. 본 논문은 음향-구조 연성해석 기법을 사용하여 펌프 맥동 가진으로 인한 해석을 위해 노심지지배럴 주변의 유체와 구조의 연성을 고려하여 해석하는 방법론을 제안하였다. 해석결과는 미국 Palo Verde 1호기 종합진동평가 프로그램 발전소 시험결과와 잘 일치한다. 따라서 제안된 해석 방법론은 펌프 압력맥동에 대한 노심지지배럴의 구조응답을 평가하기 위한 효과적 방법으로 판단된다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2003년도 춘계학술발표논문집
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• pp.288-290
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• 2003

Artificial heart is divided by pulsation flow type and continuous flow type according to blood circulation pattern. Axial flow blood pump is a kind of continuous flow type artificial heart. Axial flow blood pump would be different pump performance according to impeller's shape and rotating velocity. Pump performance be able to compare by flow rate according to differential pressure and Impeller's rotating velocity. It confirms Impeller model of better efficiency according to compare Pump performance of axial flow blood pump using CFD with actual experiment result.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.1099-1102
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• 2017

액체로켓엔진용 연료펌프의 캐비테이션 시험 중 입출구 배관과 펌프 케이싱에서 계측된 고주파 신호를 분석하였다. 각각의 데이터의 RMS 값을 캐비테이션 수에 따라 표현하였다. 측정 결과는 산화제펌프의 결과와 비교하였으며, 캐비테이션 불안정성의 영향도 검토하였다. 산화제펌프와 연료펌프 고주파 신호 사이에 유사성이 확인되었다. 또한, 캐비테이션 불안정성은 연료펌프 출구 배관 압력섭동에 영향을 주었다.

• Nuclear Engineering and Technology
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• 제40권3호
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• pp.213-224
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• 2008

The pumping of coolant in a liquid metal fast reactor may be performed with an annular linear induction electro-magnetic (EM) pump. Linear induction pumps use a traveling magnetic field wave created by poly-phase currents, and the induced currents and their associated magnetic field generate a Lorentz force, whose effect can be the pumping of the liquid metal. The flow behaviors in the pump are very complex, including a time-varying Lorentz force and pressure pulsation, because an induction EM pump has time-varying magnetic fields and the induced convective currents that originate from the flow of the liquid metal. These phenomena lead to an instability problem in the pump arising from the changes of the generated Lorentz forces along the pump's geometry. Therefore, a magneto-hydro-dynamics (MHD) analysis is required for the design and operation of a linear induction EM pump. We have developed a time-harmonic 2-dimensional axisymmetry MHD analysis method based on the Maxwell equations. This paper describes the analysis and numerical method for obtaining solutions for some MHD parameters in an induction EM pump. Experimental test results obtained from an induction EM pump of CLIP-150 at the STC "Sintez," D.V. Efremov Institute of Electro-physical Apparatus in St. Petersburg were used to validate the method. In addition, we investigated some characteristics of a linear induction EM pump, such as the effect of the convective current and the double supply frequency (DSF) pressure pulsation. This simple model overestimated the convective eddy current generated from the sodium flow in the pump channel; however, it had a similar tendency for the measured data of the pump performance through a comparison with the experimental data. Considering its simplicity, it could be a base model for designing an EM pump and for evaluating the MHD flow in an EM pump.

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.332-341
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• 2010

Standard dimensionless parameters cannot simultaneously represent all operation modes of a pump-turbine. They either have singularities at E=0 and multiple values in the 'unstable' areas, or else get singular at n=0. P. Suter (1966) introduced an alternative set of variables which avoids singularity and always remains unique-valued. This works for non-regulated pumps but not so well for regulated machines. A modification by C.S. Martin avoids distortion at low load. The present paper describes further improvements for the representation of torque, and for closed gate (where Suter's concept does not work). The possibility to interpolate across all operation modes is likewise useful for representing other mechanical parameters of the machine. Practical application for guide vane torque and pressure pulsation data is demonstrated by examples.