• Journal of Korean Society of Rural Planning
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• v.4 no.2
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• pp.20-28
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• 1998

A small wastewater collection system for rural area was reviewed and the small diameter gravity (SDG) was thought to be the most appropriate. The pilot-scale field experiment was performed for 15 months and the result is presented. The wastewater used for experiment was the effluent of septic tank in Kon-Kuk University, and components are similar to normal domestic wastewater. The SDG experimental system included 2" PVC pipe and reverse-sloped lower section is included. No clogging problem by solids was experienced at the points where flow direction changed. The pipe-breaking by freezing was experienced during the cold weather, thus proper protection may be required where severe weather is expected.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.95-99
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• 2001

As a way to use energy effectively, the present study is aimed at investigating the performance characteristics of a Single Effect LiBr/Water Absorption Refrigerator using a low temperature driving heat-source. It was carried out by changing the driving heat-source temperature, the cold water outlet temperature(the refrigeration load), the cooling water inlet temperature, and the weak solution flow rate and this study compares the performance characteristics of refrigerator against the existence and non-existence of the Recirculation of the Weak solution which is used as a method to improve the performance of refrigerator. In case of Recirculation of the weak solution, more improved the Refrigeration Capacity and COP was obtained, and these effects became more larger in the high temperature of driving heat-source and large quantity of solution.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.310-317
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• 2002

In the present study, an experimental study of natural convection in a partitioned 2D square enclosure has been carried out. The square enclosure consist of two adiabatic vertical walls and the upper cold and the lower hot walls. A partition is positioned perpendicularly at the center of the left vortical insulated wall. The PIV measurements were performed with the variations of Rayleigh number, partition length and inclination of the enclosure. The working fluid is water with Prandtl number of 6.996 at 20$\^{C}$. The captured images were analyzed by using a cross-correlation (two-frame/single-exposure) PIV method.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.277-277
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• 2019

하천 유량측정은 대부분의 업무가 야외에서 진행되기 때문에 사고위험에 항상 노출되어 있다. 특히. 교통, 수상안전 사고 등 사회적 안전사고에 대해서는 큰 노력을 기울여 대비하고 있으나, 폭염, 한파 등 자연적 안전사고에 대해서는 아직 대비가 미비하다. 본 연구에서는 겨울철 한파로 인해 발생할 수 있는 안전사고를 예방하고자 한파위험지수(CWRI)를 PSR 구조체계를 통해 제안하였다, 압력, 상태, 반응 지수 산정을 위해 각 요인에 대한 세부지표를 선정하고, 각 지수에 대한 가중치는 엔트로피 방법을 이용하여 한파위험지수를 제안하였다. 그 결과, 전국 14개 광역시도 중 서울특별시가 가장 높고 경상남도가 가장 낮은 한파 위험지수를 보였다. 이러한 결과를 토대로 겨울철 유량측정 시 측정 인원에 대한 안전 계획을 수립하여 안전사고 예방 효과를 높일 것으로 판단된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.6-6
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• 1999

국가우주개발의 중장기 계획에 따른 우주 발사체 개발의 일환으로, 한반도 대기상태측정 등을 위한 고성능 과학관측로켓의 국산화를 위하여 항공우주연구소를 중심으로 여러 기관에서 연구가 진행되고 있다. 액체로켓을 주 추진체으로 삼고 있기 때문에 로켓의 안정적인 연소와 성능 향상이야말로 발사체 개발에 핵심이라고 할 수 있다. 액체로켓의 경우, 초기점화는 고체시동장치 또는 액체시동장치에 의한 방법 등으로 구분될 수 있다. 본 연구는 액체시동장치 중 hypergolic으로 초기점화를 하고 뒤이어 주추진제(LOX/kerosene)를 내보내어 주연소를 할 수 있는 Unlike impinging Quadlet injector(3 on 1)의 연소성능 이해와 예측을 위해 Cold flow test를 기초로 수행되었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.855-861
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• 2008

Micro wave rotor is expected to improve the performance of micro gas turbines drastically. In the present study, a micro wave rotor test rig was designed and built for micro gas turbines of 1-10 kW output range, and its test runs were carried out with cold air flow. In the previous experiments, the leakage loss had large influence on its operating condition. Therefore, abradable coating was applied on the end walls to achieve the operation with zero clearance for leakage reduction and its improvement on the operating condition is discussed in this study.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.369-376
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• 1988

Among several methods to solve the unbalanced electric power load, the Ice Storage System (ISS) for the air conditioning is relatively easy to realize and gives big effect on balancing the electric power load. The goals of this study are to develop the practical ISS for the air conditioning through the design, manufacturing and performance test of the experimental ISS (size $0.335m^3$, cold storage capacity 14200 kcal, IPF 0.4). Thermal fluid motion inside the ice storage tank during cooling storage and cooling release are studied. The data are analyzed by the dispersion analysis and optimal design conditions are derived from the result.

• Journal of ILASS-Korea
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• v.24 no.2
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• pp.66-72
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• 2019

Diesel vehicles suffer from poor starting and running problems at cold temperatures. Diesel vehicles have the characteristic that CO and PM are reduced or similarly discharged when going from low temperature to high temperature. In this study, a bypass type piezo injector for electronic control based common rail injection system was used. Numerical analysis using injector drive analysis model was performed to analyze injector drive and internal fuel flow characteristics according to fuel temperature change. The results show that the rate of density change due to the fuel temperature is proportional, and that the effect of the kinematic viscosity is relatively large between $-20^{\circ}C$ and $0^{\circ}C$. Comparing the results of temperature condition at $0^{\circ}C$ and $20^{\circ}C$, it is considered that the viscosity is more correlated with the needle displacement than the pressure chamber of the delivery chamber.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1412-1420
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• 2018

An experiment was performed using the large-scale test facility (LSTF), which simulated a 1% vessel upper head small-break loss-of-coolant accident with an accident management (AM) measure under an assumption of total-failure of high-pressure injection (HPI) system in a pressurized water reactor (PWR). In the LSTF test, liquid level in the upper head affected break flow rate. Coolant was manually injected from the HPI system into cold legs as the AM measure when the maximum core exit temperature reached 623 K. The cladding surface temperature largely increased due to late and slow response of the core exit thermocouples. The AM measure was confirmed to be effective for the core cooling. The RELAP5/MOD3.3 code indicated insufficient prediction of primary coolant distribution. The author conducted uncertainty analysis for the LSTF test employing created phenomena identification and ranking table for each component. The author clarified that peak cladding temperature was largely dependent on the combination of multiple uncertain parameters within the defined uncertain ranges.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.6 no.4
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• pp.255-261
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• 1977

This study was concerned with the performance of solar air heater using parallel channels. Heat transmission model was developed and fabricated to increase the economic feasibility for solar heating system by using the cheap zinc plate. The prformance was discussed as a function of mass flow rate, and plate, inlet and outlet temperatures. Experimental results show that heat transmission model is sufficient for the analysis of thermal characteristics of air heater and collection efficiency is better than the domestic water heater, as the range 32-49 percent. Collection efficiency in the 2 layers of glass cover is better than that in 1 layer, so it is considered better to use the 2 layers of glass cover during the cold winter season in Korea.