• Fire Science and Engineering
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• v.27 no.1
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• pp.20-25
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• 2013

This study is experimentally analyzed to extract the major parameters affecting the performance of the smoke-control system and the relations of pressure difference between vestibule and supply air pressure zone effect of supply mass flow rate and leakage area in the smoke-control zone. To obtain this, the mock-up building of three-story scale with a total of 10 compartments was constructed, and several apparatus were also installed for in-situ measurement of the ventilation flow rate, pressure difference between compartments, smoke defensive air velocity, the opening-closing force of door, etc. This article show that pressure difference in the smoke-control zone is significantly related with leakage area of vestibule in low pressure region, leakage area of supply air pressure in over pressure region and both of them in pressure control region when the pressure control range of damper is 45 Pa~55 Pa.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.529-537
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• 1992

Airlift pumps were tested to evaluate their pumping and aeration capacities. The pumps were 34.5 inch long made of 2, 3, 4 and 6 inch nominal diameter PVC pipes. An one hp air blower was used to supply the air. The air-flow rate was measured by an anemometer type air-flow meter and air pressure was level changes in a water tank from which water was pumped. Aeration by the pumps was tested by the standard aeration test method with the center of pump outlet positioned 3 inches above water surface. Oxygen concentrations in water were measured to determine aeration rate. As pumping head increased by water level draw-down in the tank water flow decreased while air flow increased. The reduction rate of water flow was higher with 4 and 6-inch pumps. Small pumps showed very minor changes in the reduction. Aeration rates were similar among 3, 4, and 6 inch pumps. With one hp air blower 6-inch pump at the minimum pumping head achieved the best performance in terms of water circulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.29-32
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• 2009

This study is for development combustion test facility of liquid rocket engine system using hydrogen peroxide/kerosene as propellent. For this new facility, we construct thrust measure system, propellent supply system, control and data acquisition system. To perform 200N liquid rocket engine combustion test, operation scenario and sequence were designed. Result of combustion test propellents were supplied to engine stably and confirm of development combustion test facility very well.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.118-121
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• 2007

수소 스테이션의 수소분리정제를 위한 Compact 형 PSA를 연구하였다. 수소 스테이션의 공정과정 중에서 수소 분리를 위한 PSA 장치는 에너지효율면에서 장점을 가지고 있지만 부피가 커서 많은 부지를 차지하는 단점이 있다. 수소 PSA의 이러한 단점을 줄이기 위하여 하나의 흡착탑 안에 다른 흡착탑을 넣는 Dual bed 형태의 Compact형 수소 PSA공정을 연구하였다. Compact형 수소 PSA는 하나의 bed안에 다른 하나의 bed를 넣음으로써 시스템이 차지하는 부피를 줄이는 한편, inner bed와 outer bed사이의 열교환 효과가 나타나기 때문에 그 효율을 높일 수가 있다. Compact형 Dual bed는 활성탄으로 충진하였고 공급 기체로는 4성분 수소 혼합물 ($H_2/CO/CH_4/CO_2$, 69:2:3:26 vol.%)를 사용하였다. 흡착탑의 동특성을 알아보기 위하여 공급유량 7LPM, 흡착압력 9atm의 조건으로 파괴 실험을 수행하였다. 또한, Compact형 흡착탑의 열교환 효과가 PSA공정에 미치는 영향을 보고자 한 쪽 탑에서 흡착을 할 때, 다른 탑에서 탈착이 일어나는 실험을 하였다. 그리고 P/F ratio에 따라 Compact형 PSA 공정 실험을 하고 Compact형 흡착탑과 같은 부피의 일반 두 탑 PSA 공정을 시뮬레이션 값과 비교함으로써 Compact형 PSA의 성능을 알아 보았다. 그 결과 Dual bed PSA는 작은 부피를 차지하는 장점뿐만 아니라 열적 효과로 인하여 기존의 단일 흡착탑 PSA에 비하여 보다 높은 효율을 나타내면서 우수한 수소 분리 성능을 보여주었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.2
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• pp.32-39
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• 2005

The effectiveness of the pogo suppression device (PSD) on the response of the piping system simulating the fuel (or oxidizer) supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $((0\~2)\times10^{-3}m^3)$ and three different baffle hole diameters (5, 50, 115mm). Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, while the fluctuations of the main tube pressure and the flow rate damped down considerably. The resonance frequency decreased with the increase of the PSD inlet restriction (or the decrease of the baffle hole diameter), though slightly. However, with a larger inlet restriction, the PSD pressure wave showed a delayed response with the smaller amplitude compared to the pressure variation in the main tube.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.526-530
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• 2009

본 연구은 자동차용 가솔린엔진에 장착되는 인젝터의 연료공급 특성에 대한 것으로, 가솔린 엔진의 전자제어식 포트 연료분사는 분무장치와 흡기포트의 최적화 및 분무특성이 우수해야 엔진의 성능 향상 및 배기가스 저감의 목적을 이룰 수 있다. 4홀과 12홀 인젝터의 장착각 변화와 포트 마스킹의 형상변화에 따른 벽유량을 측정?분석하였고 분무가시화 실험을 통하여 분무성장과정과 분사각, 연료미립화 및 분무도달거리를 분석하였다. 벽류측정 실험을 통하여 벽류는 미립화정도와 흡기유동과 유속에 가장 큰 영향을 받는 것으로 판단되며, 12홀 인젝터 대비 4홀 인젝터는 분무압력에 따라 분무특성의 변화량이 크게 나타났다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.456-459
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• 2011

The Dual-type Solenoid Valve was developed for a domestic production of a fuel-supply valve on the satellite attitude control thruster system. The satellite valve using a hydrazine as a fuel must fulfill the cycle life, shock, vibration and the environment of an extremely low temperature In addition to the basic performance of the response time, mass flow and leakage etc.. in this paper, the design, production and performance experiment using the nitrogen pneumatic equipment were conducted.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.298-301
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• 2011

본 연구에서는 지하 방호공간에서 화재가 발생한 경우 워터커튼 시스템에 의한 연기의 차단효과와 화재제어 특성을 분석하였다. 이를 위해서 분사각도 $180^{\circ}$, 오리피스 직경 8.2 mm의 노즐과 지하방호 공간용 실화재 실험 장치를 제작하였으며, 화재강도 1.5 MW 기준 A급 1단위 화재 실험으로부터 온도분포와 가시도를 측정하여 연기의 차단효과를 확인하였다. 화재제어 특성을 분석하기 위해서 NIST(National Institute of Standards and Technology)의 해석프로그램인 FDS(Fire Dynamic Simulator)를 사용하여 동일한 실험조건에서 온도분포를 비교하였으며 노즐의 설치개수 변화에 대한 화재해석 및 실험결과로부터 워터커튼 시스템은 노즐의 설치위치와 개수, 화원으로부터의 거리, 제연 등의 설비 조건과 분사 노즐의 특성, 공급 유량 등이 중요한 상관관계를 갖고 있음을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.233-234
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• 2021

The freezing of the water meter due to the cold wave in winter causes safety accidents caused by freezing and suspending the supply of tap water and various inconveniences. In this study, the water meter develops a test device similar to the environment in which the actual freezing occurs and tests repeatedly by changing the temperature, humidity, flow rate, pressure, valve improvement, pump operation status, etc. Based on the data obtained through this, it is planning to predict the timing of freezing by applying AI technology to correlation between freeze influencing factors.

• Resources Recycling
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• v.9 no.3
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• pp.13-21
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• 2000

This study describes to analyze the heat transfer characteristics of waste solvent recovery system using a double pipe heat exchanger heating solvent by the hot oil. The solvent recovery system consists of the feeding pump, the double pipe heat exchanger, the vacuum spray chamber, and the condenser. A double pipe heat exchanger consists of the first section to conduct the heating of solvent to the thermal saturated point and the second section to evaporate the saturated solvent. The heat transfer area for vaporization of water, benzene and alkylbenzene was predicted by the heat balance modelling and experimentally measured from the temperature distribution as a function of solvent flow rate and heating temperature. The required heat transfer area for vaporization was increased with increasing solvent flow rates and with decreasing heating temperatures due to decreased quantity of transferred heat per the unit area. Theoretical modelling of the heat transfer area for solvents vaporization in the pipe showed good agreement with experimental results. Results showed to be suitable for the waste solvent recovery using a double pipe heat exchanger.