• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1123-1126
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• 2003

In this research 4 plate type ER-Valves which have same surface but different width and length are designed and an experimental apparatus is constructed. With this experimental apparatus, flow rate and pressure drop of ER fluid flowing in ER-Valve are measured by varying electric field strength of ER-valve, and relation between valve types and pressure drop is also experimented. ER fluid is made silicon oil mixed with 40wt% starch having hydrous particles. The pressure drop according to the strength of electric field by differential pressure gauge in the present ER-Valve was used. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.1
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• pp.63-68
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• 2004

Recently ER fluids are put to practical use in fluid power industry field. As only with electrical signal change to the valve in which ER fluid flowing, ER fluid flow is controlled, so devepment of simple ER valves have been tried. In this case a technical problem is to check the pressure drop caused from flow rate change in valves because the pressure drop is very small. In this study ER valves are designed and manufactured, and small pressure drop induced from flow rate change is checked by pressure transducer which is made with appling strain gage. The ER valves and pressure drop check method are considered to be applied to the fluid power industry.

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.143-148
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• 1997

Differential pressure Venturi cone flowmeter is an advanced flowmeter which has many advantages such as wide range of measurement, high accuracy, excellent flow turndown ratio, low headless, and short installation pipe length requirement, etc. Like other differential pressure flowmeter, Venturi cone flowmeter uses the law of energy conservation, but its shape and position make it perform better than others. The cone acts as its own flow conditioner and mixer, fully conditioning and mixing the flow prior to measurement. For the analysis, we use Reynolds-averaged Navier-Stokes equations and $k-{\omega}$ turbulence model. The equations are fully trans-formed in the computational coordinates, the pressure-velocity coupling is made through SIMPLER algorithm, and the equations are discretized using analytic solutions of the linearized equations(Finite Analytic Method). At the end of the paper, using the result of analysis, We propose a new shape of cone with the hope of drag reduction and high performance.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.275-277
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• 2016

본 논문에서는 Door Fan Test 수행 사례를 중심으로 사전 준비에 필요한 사항에 대해 분석하였다. 분석 결과 관통부 주위 개구부, 벽체 틈새 개구부 등 방화구역의 누설부위를 통해 약제가 누출되는 문제가 있었다. 원인으로는 전기배선 공사로 인해 내화충전된 부분을 제거하고 공사 후 다시 충전하지 않는 경우, 벽과 천장사이의 틈을 내화 실란트 등으로 마감을 하지 않은 경우가 대부분이었다. 이와 같이 누설부위가 많은 경우 테스트의 결과 불합격이 나오게 되며, 이러한 문제점을 개선하기 위해 사전현장조사를 통해 방호구역의 누설부위를 조사하고 보완조치를 진행한 후 테스트를 수행하는 절차가 필요하였다. 한편, 테스트 운영에 관한 사항으로는 해당 실(room)을 위한 충분한 유량 미확보, 장애물로 인한 와류형성, 차압측정구의 설치문제 등이 있었다. 이를 개선하기 위해서 공기를 유입하는 실은 외부로부터 충분한 공기유입이 있어야하며, 팬 앞의 장애물을 제거하거나 팬의 설치 위치를 조정하는 것이 필요하며, 공기의 유동이 가장 적은 곳에 측정구를 설치하는 등의 조치가 필요하다.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.153-159
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• 2004

We have investigated the feasibility of using differential pressure(pressure drop) of gas turbine meter to diagnose turbine performance degradation caused by mechanical wearing damage and/or dirt buildup or erosion. If the differential pressure between the upstream piping and the throat of a turine meter can be correlated to meter flow rate over the operating range of the meter, then a relatively simple differential pressure measurement in the filed might be used to detect meter performance changes. To test this method, we have conducted two experimental simulation on Straightener Integrated Type(SIT) turbine meter. One is fur dirt buildup on turbine blade, the other is for eccentricity of the blade. Results show that this method provide a reliable measure of performance degradation and is useful maintenance indicator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.892-897
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• 2020

Previous plastic heat exchangers are expensive because the mold must be newly manufactured depending on the air conditioning space. On the other hand, danpla is so thin that the heat exchange performance is excellent. Moreover, danpla can be used easily in ventilation systems in view of fabrication. This study proposes correlations for the cooling performance of an indirect evaporative cooling system. The experimental apparatus consisted of a heat exchanger, spray nozzle, fan, thermostat, pump, and measuring sensors for temperature, humidity, and airflow rate. The results showed that the effectiveness decreased gradually as the airflow rate increased. In addition, there was an optimal condition in terms of effectiveness. The performance prediction correlations were determined using the experimental data from various conditions. The proposed correlations showed performance accuracies within 4 % error.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.47-52
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• 1998

To eliminate foreign substance like metal rust and sand in natural gas pipeline, 250um strainer filter is used present in Korea Gas Corporation. But particles smaller than 250um passing the filter have bad effects to the valves and the measuring equipments. In order to eliminate small paticle in the pipeline, it is necessary to cut down the pore size of filter When we cut down the pore size of filter, the pressure difference between the front of filter and that of the rear part is increasing and disturb normal condition of gas supply. So it is very important to control the condition between the pore size of filter and the pressure difference. In this study, using head loss coefficient K, the estimation method of efficiency of gas filter according to the pore size and the pressure difference is presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.723-729
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• 2019

Turbochargers are an effective device to reduce the fuel consumption. In this study, the mass flow rate of pulsating flow in the twin-scroll turbocharger for the gasoline engine of passenger vehicles was measured. Pulsating flow was achieved using a pulse generator and the mass flow rate of the unsteady pulsating flow was analyzed by comparing it with those of the steady flow. The pulse generator consisted of a rotating upper plate and a fixed lower plate. To measure the mass flow rate of unsteady flow, the orifice flow meter equipped with the difference pressure transducer was used. To analyze the low speed performance of the turbocharger, the measurement was carried out in the speed of turbocharger from 60,000rpm to 100,000rpm. The mass flow parameters of the unsteady pulsating flow showed a large difference compared to those of the steady flow. Those of the unsteady flow showed the hysteresis loop surrounding the mass flow parameters of the steady flow and the maximum variation of the mass flow parameters were 5.0 times those of the steady flow. This phenomenon is the result of the filling and emptying the turbine volute space due to pulsating flow.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.281-281
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• 2010

ITER 블랑켓 시험모듈(TBM)의 액체형 증식재 성능 시험용 루프의 설계를 완료하였고 현재시험용 루프를 제작 및 설치중이다. 액체형 증식재 성능 시험용 루프의 핵심 구성 부품인 액체 저장용 탱크, 전자석, EM 펌프들과 이들 장치들의 전원장치 및 제어장치를 제작 완료하였다. 액체형 증식재 성능 시험용 루프 설치를 위한 데크를 제작하였으며, 제작된 실험 데크의 총 지지하중은 10 톤 이상이다. 루프설치대 위에 성능 시험용 루프가 설치되며 루프 설치대는 $3\;m\;{\times}\;2.4\;m$ 의 직사각형으로 제작되었으며, 실험 종료 및 유지 보수 시 액체증식재의 drain을 고려하여 전체 루프는 각도 조절이 가능하도록 제작되었다. 루프내의 유량을 측정하기 위한 유량계, 전자석 자장의 변화에 따른 압력의 변화를 측정하기 위한 차압센서가 전자석의 양단에 설치되며, 시험용 루프에 흐르는 액체금속(PbLi) 및 루프관의 온도를 측정하기 위한 열전대가 설치된다. 루프 설치대를 기울였을 때 루프의 최상부에 액체금속 저장고 및 레벨센서를 설치하여 루프 내에 액체금속이 가득 채워졌는지를 레벨센서로 확인하며 루프 내에 잔존하는 기체가 저장고를 통하여 외부로 배출되게 하였다. 액체형 증식재 성능 시험용 루프 설치 후 실험은 고체 상태의 PbLi를 액체 저장용 탱크에 장착한 후 탱크의 열선의 온도 제어에 의한 PbLi의 용융점 확인, 시험용 루프에서의 전자펌프 성능 평가 등의 시험의 기본적인 실험을 수행한 후 자기장 환경에서 MHD 평가, 증식재의 순도 유지, 구조재의 부식 등의 시험을 수행할 예정이다.

• Fire Science and Engineering
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• v.33 no.4
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• pp.35-40
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• 2019

In this study, the mass flow rate of the heat release rate equation, which is the major factor of the oxygen consumption method, was analyzed for the fundamental investigation of the cone-calorimeter (5 m length and 0.3 m diameter). The shapes of a completely empty inside, 3 mm pore diameter mesh and pore diameter 10 mm honeycomb with 0.76 porosity were constructed using the cone-calorimeter. To calculate the mass flow rate, four bi-directional probes and thermocouples were installed in a uniform position in the vertical direction of flow. The velocity gradient and flow perturbation were measured from the increase in Reynolds number. As the flow capacity increased, the speed gradient increased in all three shapes relative to the turbulence intensity. In addition, the deviation of extended uncertainty to the mass flow was completely low in the order of empty space, mesh (d_p = 3 mm) and honeycomb (d_p = 10 mm and 𝜖 = 0.76) at the 95% confidence level. The results can be used in designs to improve the flow stability of the cone calorimeter.