• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.322-325
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• 2007

This paper shows the development procedure of the low pressure LOX feed system which is used in the liquid rocket with a turbopump. Korean Air has cooperated with KARI in developing the LOX feed system to turbopump. The LOX feed system is characterized with cryogenic temperature and the thin-thickness tube for weight saving. The system in this project is composed with a main feed line and a recirculation line for the LOX temperature conditioning. Each piping system has many components, namely, bellows, filter, orifice, valves, flange and support. In this paper, system design & manufacturing, structural & thermal analyses, and component tests are explained. Finally, the system was assembled to the KARI's PTF test facility and functioned well to meet its required performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.209-216
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• 2024

Land shrimp farms can control the growth environment more stably than coastal ones, making them advantageous for high-quality, large-scale production. In order to maintain an optimal shrimp growth environment, various factors such as water circulation, maintaining appropriate water temperature, oxygen supply, and feed supply must be managed. In particular, failure to properly manage water quality can lead to the death of shrimp, making it difficult to have people stationed at the farm 24 hours a day to continuously manage them. In this paper, to solve this problem, we design an integrated monitoring system for land farms that can be operated with minimal manpower. The proposed design plan uses IoT technology to collect real-time images of land farms, pump status, water quality data, and energy usage and transmit them to the server. Through web interfaces and smartphone apps, administrators can check the status of the farm stored on the server anytime, anywhere in real time and take necessary measures. Therefore, it is possible to significantly reduce field work hours without the need for managers to reside in the farm.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.630-636
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• 2008

1000MW급 증설과 관련하여 발전소 주변지역으로부터 민원이 제기된 3000MW급 화력발전소는 넓은 평지에 위치하여 발전소의 영향이 그대로 주변지역에 전달되는 상태임에도 일상 소음레벨이 환경 기준치를 만족하는 상태였으나 향후 증설에 따른 소음도 증가에 대비하여 소음영향을 예측하고 저감 대책을 검토하였다. 대형 화력발전소의 옥외소음원은 Booster fan, I.D.fan, 주변압기, 대형 철탑, 해수순환수 펌프 전동기, 증기방출관 등이 있다. 대상 주거지역의 경우는 대형팬에 의한 지향성이 크게 나타났다. 따라서, 발전소가 주변지역에 주는 소음별 기여도를 평가하고 영향이 큰 대형팬에 대한 대책으로써 기기주변에 방음벽을 설치하는 방안과 함께 소음원의 크기를 저감시킬 수 있는 소음기 대책을 추천하여 증설 예정호기를 비롯한 기존 호기중 주거지역에 영향이 큰 3000MW에 대하여 수립함으로써 소음저감 목표치를 달성하는 결과를 도출하였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.389-396
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• 2018

The Kori-1 Nuclear Power Plant (NPP), WH 2-Loop Pressurized Water Reactor (PWR) operated for approximately 40 years in Korea, was permanently ceased on June 18, 2017. To reduce worker exposure to radiation by reducing the dose rate in the system before starting main decommissioning activities, the permanently ceased Kori-1 NPP will be subjected to full system decontamination. Generally, the range of system decontamination includes Reactor Pressure Vessels (RPV), Pressurizer (PZR), Steam Generators (SG), Chemical & Volume Control System (CVCS), Residual Heat Removal System (RHRS), and Reactor Coolant System (RCS) piping. In order to decontaminate these systems and equipment in an effective manner, it is necessary to evaluate the influence of the flow characteristics in the RCS during the decontamination period. There are various methods of providing circulating flow rate to the system decontamination. In this paper, the flow characteristics in Kori-1 NPP reactor coolant according to RHR pump operation were evaluated. The evaluation results showed that system decontamination using an RHR pump was not effective at decontamination due first to impurities deposited in piping and equipment, and second to the extreme flow unbalance in the RCS caused deposition of impurities.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.48-53
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• 2008

The condensation heat transfer coefficients of R-22 and R-410A in a small diameter tube were investigated. The main components of the refrigerant loop consist of a receiver, a variable-speed pump, a mass flowmeter, an evaporator (preheater), and a condenser (test section). The test section consists of smooth, horizontal copper tube of 3.38 mm outer diameter and 1.77 mm inner diameter. The refrigerant mass fluxes varied from 450 to $1050\;kg/(m^2s)$ and the average inlet and outlet qualities were 0.05 and 0.95. The main results were summarized as follows : the condensation heat transfer coefficient also increases with increasing mass flux and quality. The condensation heat transfer coefficient of R-410A was slightly higher than that of R-22. Most of correlations proposed in the large diameter tube showed significant deviations with experimental data except for the ranges of low quality and low mass flux.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.128-135
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• 2018

Currently, vertical closed ground heat exchangers are the most widely utilized geothermal heat pump systems and the major influencing parameters on the performance of ground heat exchangers are the ground thermal conductivity(k) and borehole thermal resistance($R_b$). In this study, the borehole thermal resistance was calculated from the in-situ thermal response test data and the individual effects of design parameters (flow rate, number of pipe, grout composition) on the borehole thermal resistance were analyzed. The grout thermal resistance was also compared with the correlations in the literatures. The borehole thermal resistance of the investigated ground heat exchanger results in 0.1303 W/m.K and the grout thermal resistance (66.6% of borehole thermal resistance) is the most influencing parameter on borehole heat transfer compared to the other design parameters (pipe thermal resistance, 31.5% and convective thermal resistance, 1.9%). In addition, increasing the thermal conductivity of grout by adding silica sand to Bentonite is more effective than the other design improvements, such as an increase in circulating flowrate or number of tubes on enhancing borehole heat transfer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.24-30
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• 2016

Vertical and standing column well ground heat exchangers have mostly been installed for ground source heat pump systems (GSHP) and thermal response tests (TRT) have been applied to evaluate the thermal characteristics for these heat exchangers. In this paper, the TRT coupled with a line source method was applied to evaluate the thermal characteristics of the horizontal ground heat exchanger (HGHX). Load tests of a HGHX were also performed to examine the daily variations of the ground and fluid temperatures associated with the daily intermittent operation of GSHP. For this test, the straight HGHX (depth 2 m, length 50 m, 8 line) was installed in Ansan city. The results showed that the variations of ground thermal conductivity of HGHX during one year were relatively small with the range of $1.43{\sim}1.64W/m{\cdot}K$, and the maximum and minimum values appeared in December and May, respectively. Load tests with heat injection rate of 6.0 kW for 10 hours per day to HGHX during twelve days were performed in June, September and December, and resulted in a ground initial temperature rise of $4.31^{\circ}C$, $3.14^{\circ}C$, and $1.21^{\circ}C$ during these days, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.615-622
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• 2015

As the development of high efficiency and high flux density LEDs, the trend of illumination lamp industry transfers from conventional-lamps to the LED-lamps. For energy efficiencies, LED lamps are superior to the conventional lamps, but they have heat problems. Especially, the heat problems are severe for the high luminance lamps. They degrade the soldering point of the metal PCB, and shorten the life cycle of LEDs. So, the solution of the heat sinking is very important to develop high luminance LED lamps. This study suggested a new method to solve the heat problems for high luminance LED lamps, and developed a LED lamp which has 1200W power. In this study, a water jacket is installed to the LED lamp, and the cooing water is circulated by a water pump.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.81-81
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• 2011

우리나라는 최근 많은 주요하천에서 생태하천으로의 복원작업이 활발하게 진행되고 있다. 견고함을 위해 예전부터 수충부에 콘크리트를 주로 사용하였으나, 생태하천으로의 복원을 위해서는 호안 조성 재료의 교체가 필요하다. 콘크리트를 대체 할 여러 종류의 자연친화적 재료 및 공법들이 개발되고 있으나, 재료에 대한 신뢰성 있는 특성 분석 자료 및 평가에 대해서는 진행되어 있지 않다. 본 논문에서는 최근 자연형 하천 조성에 사용되고 있는 소프트 백(Soft-Bag)에 대한 수리학적 특성치를 검토하기 위하여 식생 유 무에 따른 조도변화, Re수 및 Fr수를 산정하였다. 본 연구를 위하여 최대로 약 0.4cms의 유량이 통수가 가능하도록 길이 20m, 폭 2m, 높이 1m의 개수로 장치를 실내에 설치하였으며, 지하저류조를 제작하여 200톤의 유량이 순환되도록 펌프 4대를 설치 하였다. 또한, 유속의 증가를 위하여 개수로 경사장치를 설치함으로써 최대 0.005의 경사로 실험이 가능하도록 제작하였으며, 최하류부에 수문을 설치함으로써 하류경계조건에 의한 실험이 가능 하도록 하였다. 본 실험을 위하여 유량 및 하류경계조건의 변화에 따라 호안의 식생 유 무를 달리하여 실험을 통해 얻어진 데이터를 분석하였으며, 식생이 없는 경우 유량이 증가할수록 Re수 및 한계소류력이 증가하였으며, Fr수의 경우에는 하류경계조건에 따라 유속변화에 더 민감한 것으로 나타났고, 조도의 경우에는 0.01~0.025의 범위로 나타났고, 식생이 있는 경우 하류경계조건에 의한 변화의 폭이 더 작게 나타났다. 식생에 의한 유속은 하류경계조건이 낮은 경우에는 유량이 클수록 식생에 의한 변화가 크게 나타났지만, 하류경계조건이 커질수록 식생에 의한 유속의 영향은 거의 없는 것으로 나타났다.