• 한국화재소방학회논문지
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• 제26권5호
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• pp.85-91
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• 2012

소방차에 설치되는 소방펌프에 대한 방수성능 기준이 현장에서 운용하고 있는 실태와 상이한 부분이 있고, 기준이 명확하게 규정되어 있지 않아 소방공무원이 화재현장에서 소방펌프의 사용시간, 최대사용압력, 사용 호스 직경 등 사용 실태를 분석하고, 그 결과를 토대로 소방펌프에 대한 압력별, 호스 직경별 수량별로 다양하게 성능시험을 실시하였다. 현장조사 결과, 소방자동차용 소방펌프의 성능에 관한 인정기준에서 규정하고 있는 규격방수압력(0.85MPa)과 고압방수압력(1.4 MPa)보다 현장에서는 더 높은 압력을 사용하고 있는 것으로 조사되었다. 또한, 펌프의 성능시험 결과는 방수량 및 방수압력 등이 호스의 직경, 관창에 따라 현재 규정하고 있는 인정기준과 매우 상이하게 측정되었으며, 본 연구 결과로 새로운 규격을 제안한다.

• Design & Manufacturing
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• 제10권2호
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• pp.18-23
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• 2016

Injection molded thermoplastic parts may need to be coated to facilitate paint adhesion, or to satisfy other surface property requirements, such as appearance, durability, and weather resistance. In this paper, a two-component polyurethane metering system was developed for the simultaneous injection and surface coating of a plastic substrate. The system was composed of storage tanks, feed pumps, axial piston pumps, mixing head. The tank was designed to be double-jacket structured and fabricated for polyol and isocyanate, respectively. A temperature chamber was used to maintain the material temperature to be $80^{\circ}C$ during flowing from storage tank to mixing head. Inside the chamber, feed pump, low pressure filter, high pressure pump, high pressure filter, pressure sensor, flow meter were installed. A mixing head of L-type was used for homogeneous mixing of polyol and isocyanate. Inside the mixing head, a cartridge heater and a temperature sensor were installed to control the temperature of the materials. The flow rate of axial-piston pump was controlled by using closed-loop feedback control algorithm. The input flow-rates were compared with the measured values. The output error was 6.7% for open-loop control, whereas the error was below 2.2% for closed-loop control. In addition, the pressure generated through mixing-head nozzle increased with increasing flow rate. It was found that the pressure drop between metering pump and mixing-head nozzle was almost 10 bar.

• 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.

• 대한기계학회논문집A
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• 제30권1호
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• pp.52-59
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• 2006

The vibration of hydraulic piston pumps is induced by the periodically changing cylinder chamber pressure whose waveform is significantly influenced by valve plate geometry. In this study, the force input to the housing of a bent-axis type hydraulic piston pump was computed by deriving the dynamic equations of its piston and cylinder barrel. The vibration intensity of the pump was represented by the acceleration amplitude of its housing. In order to comparatively evaluate the influence of valve plate geometry on the vibration of pump housing, two different types of valve plate were tested. The computed results showed good agreement with the experimental data, indicating that the vibration acceleration of pump housing is rather dependent on the variation amplitude of balance coefficient than the changing slope or overshoot of cylinder chamber pressure. It was also confirmed that the design effect of valve plates could be directly examined out by monitoring the vibration acceleration of pump housing.

• 유공압시스템학회논문집
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• 제7권1호
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• pp.1-5
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• 2010

This paper presents the experimental results of the radial piston type oil pump with new mechanism for a metal diaphragm hydrogen compressor. Generally, metal diaphragm type hydrogen compressor systems are operated by oil hydraulic power. In this system an oil compensating pump has been demanded to compensate for a leakage oil head chamber. The metal diaphragm type hydrogen compressor consists of an oil compensating pump, commonly used hydraulic piston pump and driven by main crank shaft. The radial piston type oil compensating pump with new rolling contacted piston mechanism is developed and experimented. The developed piston element of the radial piston pump consists of piston, steel ball, return spring, two check valves, eccentric cam and ball racer. In this study, designed 4 type pistons as and orifice hole. Operating characteristics and pressure ripple characteristics are tested under no load to 60bar loaded with every 20bar increasing step and pressure ripple and flow rate are experimentally investigated.

• 한국유체기계학회 논문집
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• 제14권5호
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• pp.18-23
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• 2011

A CFD analysis method is developed and applied for investigating the gas flow and the byproduct particle trajectory in Roots type vacuum pump. The internal fluid flow and thermal fields between the rotors and the housing of vacuum pump are analyzed by using the dynamic mesh, the numerical methods for unsteady 2-D Navier-Stokes equation and the standard k-$\varepsilon$ turbulence model of the Fluent code. Coupled with the flow simulation results, the particle trajectory of the byproduct flowing into the pump with gas stream is analyzed by using discrete phase modeling technique. The CFD analysis results show the pressure, the velocity and the temperature distributions in pump change abruptly due to the rotation of rotors, and back flows are produced due to the strong reverse pressure gradients at rotor/rotor and rotor/housing clearances. The predicted byproduct particle trajectory results also show the particles impinge on the clearance surfaces between the housing and the rotor of pump and then may form the deposit layer causing the failure of pump.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.341-346
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• 2004

A low NPSH and high pressure fuel pump has been designed for a turbopump system. The fuel pump has an axial inducer and a centrifugal impeller. A meanline method has been established for the preliminary design and performance prediction of pumps at design or off-design points. KeRC carried out a model testing of the fuel pump with water as a working fluid at the reduced speed. Predicted performances by the method are shown to be in good agreement with experimental results for cavitating and non-cavitating conditions. The established meanline method can be used for the performance prediction and preliminary design of high speed pumps which have a inducer, impeller and volute. In the current study, the three dimensional viscous flow in the fuel pump was investigated through numerical computation. A modified design of the fuel pun was generated to improve pump performance by utilizing CFD results. The modified fuel pump was experimentally tested by ROTEM and KARI. The measured non-cavitating and cavitating performance showed a good agreement with designed performance.

• 한국압력기기공학회 논문집
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• 제8권3호
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• pp.23-27
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• 2012

A seawater pumps in the nuclear power plant is responsible for providing cooling water to other components all the time. Because of the depreciation, the seawater pump with current impeller consumes too much power for maintaining the total head. Therefore the objective of this study is to reduce power with maintaining certain the total head by cutting the current impeller. By using a commercial CFD code, FLUENT, the overall performance of seawater pump with current and modified impeller was simulated. Also Affinity law was applied at pumps with various impeller diameter and evaluated the validity of the affinity law. The numerical results show that the pump efficiency is quite irrelevant to the diameters of the impellers and the pump efficiency becomes worse over the designed flow rate. And affinity law result and numerical one show good agreements at small change of impeller diameter. One of the impeller diameters was decided to modify and was applied to the nuclear power plant with the numerical study above.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1229-1230
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• 2013

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.762-763
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• 2012