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Ohm, In-Yong;Park, Chan-Jun
- Journal of Mechanical Science and Technology
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- v.16 no.11
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- pp.1457-1469
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- 2002
This paper is the first of several companion papers, which investigate axial stratification process and its effects in an Sl engine. The axial stratification is very sophisticate phenomenon, which results from combination of fuel injection, port and in-cylinder flow and mixing. Because of the inherent unsteady condition in the reciprocating engine, it Is impossible to understand the mechanism through the analytical method. In this paper, the ports were characterized by swir and tumble number in steady flow bench test. After this, lean misfire limit of the engines, which had different port characteristic, were investigated as a function of swirl ratio and injection timing for confirming the existence of stratification. In addition, gas fuel was used for verifying whether this phenomenon depends on bulk air motion of cylinder or on evaporation of fuel. High-speed gas sampling and analysis was also performed to estimate stratification charging effect. The results show that the AFR at the spark plug and LML are very closely related and the AFR is the results of bulk air motion.
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이희성;강부병
- Tribology and Lubricants
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- v.18 no.4
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- pp.305-311
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- 2002
Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. A braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two types of brake with different sizes in stop and hold braking modes. Plasma spray coating technique was also used to coat the discs with ceramic powder. During the test four commercial brake pads were coupled with discs. Ceramic coated discs showed good stability in friction coefficient at high speed and high energy braking conditions. But they caused large wear loss of pad mass compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc. it showed fluctuating friction coefficient at high speed but small wear loss of pad mass compared with ceramic coated discs.
https://doi.org/10.9725/kstle.2002.18.4.305 인용 PDF KSCI

Yang, Hyung-Jae;Shin, Eung-Bai;Chung, Yun-Chul;Choi, Hun-Geun
- Journal of Korean Society on Water Environment
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- v.16 no.4
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- pp.533-539
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- 2000
A bench-scale reactor using SBR process was experimented with an synthetic wastewater. The main purpose of this investigation was to evaluate applicability in the field and process removal efficiencies in terms of BOD and T-P and its corresponding kinetic parameters. Removal rate of phosphorus was 77% in terms of total phosphorus. Effluent concentrations were $9.8mg/{\ell}$ BOD and $1.1mg/{\ell}$ T-P. Effluent quality was maintained consistently stable by controlling decant volume and operating cycles. The efficiency for phosphorus removal was increased due to decrease in BOD-SS loading value in the range of $0.25{\leq}$aeration time ratio${\leq}0.52$.
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김준엽;김인식;한태균
- Proceedings of the Korean Society of Propulsion Engineers Conference
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- 2000.04a
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- pp.13-13
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- 2000
일반적으로 고체추진 로켓 모타의 개발단계 때 공통적으로 수행되는 주시험(main test)으로는 추력, 압력, 회전률 등의 성능측정을 하기 위한 정적연소시험(static firing test), 내부 정수압(hydrostatic pressure)에 의한 폭발 압력 시험, 연소중이나 연소 후 케이스에 대한 굽힘 강성 시험, 이외에 노화 시험, 환경시험 등이 요구된다. 그러나 신궁과 같은 휴대용 대공 시스템의 추진기관 개발의 경우에는 사수를 보호하기 위해 여러 가지 안전장치들이 설계되고, 이러한 장치들의 성능에 대한 요구 조건들을 확인하기 위한 특수시험(specific test)들이 필요하게 된다. 이러한 특수시험을 위한 각종 시험대들을, 위에서 언급한 주시험을 위해 사용되는 정적시험대(static test bench)들과 구분하기 위해 동적 시험대(DTB : Dynamic Test Bench)라고 한다. 본 연구에서는 신궁 추진기관의 사출모타 점화에서 비행모타 점화에 이르는 일련의 비행절차를 확인하기 위한 동적 시험대 설계 및 제작, 계측장치 구성 및 데이터 획득 방법 등에 관한 내용을 소개하며, 동적 시험대에서 수회에 걸쳐 수행된 동적 시험 결과를 분석/정리하였다.
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