• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.158-162
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• 2000

Secondary flows in gas turbines, especially those associated tip clearance and labyrinth seals, have become a focus of interest for engine manufacturers. In the past, many analytical and experimental studies, which focused solely on the flows in either tip clearances or seals, have been conducted. This paper presents an analytical model that describes the flow response in a single stage turbine induced by a finite sealing gap at the turbine rotor. The flow is assumed to be axisymmetric and the analysis is done in the meridional plane. Upon going through the stage, the radially uniform upstream flow is assumed to split into two streams one associated with the seal and the other which has gone through the blades. The former is referred to as the leakage flow, and the latter is referred the as the passage flow. The passage flow is assumed to be inviscid and incompressible while the flow in the seal can be modeled as either inviscid or viscous. Thus, the model is capable of predicting the kinematic effects of labyrinth seals on the turbine flow field.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.341-347
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• 2005

To perform a cryogenic development test for Tribo-elements in a turbopump, a cryogenic bearing and seal test facility (BSTF) is designed and currently under construction in KARI. The working fluid is liquid nitrogen operating at a temperature $-197^{\circ}C$. The maximum operating pressure and volume flow rate of BSTF are 100 bar and 10 liters per second, respectively. The development tests of floating ring seals, inter-propellant seals (IPS) and cryogenic ball bearings in a turbopump will be performed using the BSTF. This paper briefly described design requirements and procedures of BSTF.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.217-222
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• 2002

본 연구에서는 가연성 폐기물을 이용한 시설원예 난방에너지 공급시스템 개발을 위하여 대형 온실 난방이나 RPC 시설에 이용할 수 있는 왕겨와 중유 겸용연소 시스템에서 중유의 연소 및 성능 특성을 분석하고자 하였다. 중요 인자로는 분사노즐의 크기(2.0, 2.25, 2.5, 3.0 GPH)와 진공압력(375, 500, 625, 750 Pa)을 설정하였으며 이에 대한 결과를 요약하면 다음과 같다. 1.진공압력 500Pa조건에서 연료 공급율이 증가할수록 연소실 벽체 열교환기 효율은 감소하고 폐열회수 열교환기와 사이클론 열교환기의 효율이 증가하였으며, 노즐 2.5GPH에서 진공압력이 커질수록 연소실 하부의 온도가 감소하였고 연소실 상부에서는 비슷한 경향을 보였다. 2, 연소온도특성, 열효율, 배기가스 성분분석 등의 결과로 볼 때 최적의 연소 조건은 노즐 2.5GPH는 진공압력 375Pa, 노즐3.0GPH는 진공압력 500Pa과 625Pa 사이로 판단되었다. 3. 배연가스내의 대기오염 성분은 모든 실험처리에서 CO 함량은 거의 없고 SO$_2$와 NO$_{x}$의 함량 또한 일반 보일러 허용기준을 만족하는 것으로 나타났다.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.126-137
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• 1993

This paper presents an efficient method for the identification of motion error sources in NC machine tools by making use of the circular interpolation test, which is often used in estimating the motion accuracy of NC machine tools. Mathematical formulae are described for motion errors due to various kinds of error sources. Two identification formulae are proposed: one is based on the frequency analysis and the other is formulated with the weithted residual method. Motion error signal is classified into two patterns, mean errors(mean of CW and CCW test signals from mean errors). The sources of the mean errors are identified by using the frequency analysis technique and the sources of the deviation errors by the weighted residual formulaltion. A menu driven, user oriented, computer program is written to realize the full steps of the proposed identificationprocedure. Then, the identification method is applied to two NC machine tools.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.27-31
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• 1996

연사기는 장섬유가 천연섬유와 유사한 섬유의 성질을 갖도록 하거나 면사, 모사 등의 단섬유사의 인장강도를 높여주기 위해서 실을 꼬아주는 기계를 가리키며 여러 가지의 연사기 가운데 생산성이 높은 2-for-1 연사기가 널리 사용되고 있다. 2-for-1 연사기는 고정된 급사 보빈과 이것을 관통하는 중공스핀들, 실이 통과하는 구멍(yarn guide)을 가진 디스크와 실을 감는 장치등으로 구성되어 있다. 고정된 보빈에서 풀려 나온 실이 스핀들을 거쳐 회전하는 yarn guide를 통과하면서 실이 한 번 꼬이고 yarn guide를 빠져나온 실이 감기면서 다시 꼬이므로 1회전당 2회 꼬이게 되어 2-for-1이라는 이름이 붙여졌다[1]. 2-for-1연사기의 스핀들은 대개 10,000-15,000rpm으로 회전하며 고속으로 올라갈수록 생산성이 증대되기 때문에 고속화를 위한 노력이 계속되고 있으나 고속화를 가로막는 중요한 애로기술의 하나가 소음, 진동저감기술이다. 본 연구에서는 스핀들 32개짜리로 특별제작된 2-for-1 연사기에서 가장 중요한 소음으로 인식되고 있는 스핀들 소음의 소음원인을 규명하고자 하였다. 소음원인의 분석에는 다중입력/단일출력(MISO)모형을 이용한 신호 해석법을 사용하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.643-649
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• 2011

For the development of butterfly valves used in liquefied natural gas (LNG) vessels, the seat tightness is one of the important factors to be taken into account in the valve-design process. An O-ring-type metal seal with a retaining ring showing good seat tightness at cryogenic temperatures has been widely used, despite the high manufacturing costs involved. As an alternative, a flexible solid metal seal offers not only sufficient tightness of the butterfly valve, meeting specification requirements, but also relatively low manufacturing costs. In this study, a design criterion to ensure the seat tightness of the butterfly valve using the flexible solid metal seal is proposed. The contact pressure can be calculated by the simulation of the frictional contact behavior between the surface of the metal seal and the valve disc. The geometry of the flexible solid metal seal is determined so that it satisfies the design criterion for sufficient seat tightness, and is verified by experiments according to BS6755 and BS6364.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.26-31
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• 2018

This paper introduces a study to improve the thermal efficiency of the district heating user control facility based on reinforcement learning. As an example, it is proposed a general method of constructing a deep Q learning network(DQN) using deep Q learning, which is a reinforcement learning algorithm that does not specify a model. In addition, it is also introduced the big data platform system and the integrated heat management system which are specialized in energy field applied in processing huge amount of data processing from IoT sensor installed in many thermal energy control facilities.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.241-246
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• 2005

This study is carried out to analyze the stability of a container crane in according to the change of a wind direction and a machinery house location when a wind load of a wind velocity, 75m/s was applied on the state stowing a container crane by a heavy wind A design wind load applied to this study was calculated in observance of 'Load Criteria of Building Structure'. And we analyzed the reactions of each supporting points according to appling a wind direction to an interval of $15^{\circ}$ in $0^{\circ}\~180^{\circ}$ and the structure stability of a container crane according to changing a machinery house location occupying $15\%$ of a container crane weight. From a results of this study, we presented a design criteria of an overturning disturbance equipment, tie-down.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1398-1407
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• 1992

The prediction of heat loss during laminar flame propagation was carried out by measurement of gas pressure and visualization of flame propagation in the constant volume combustion chamber. And to validate the prediction, the instantaneous temperature at wall of combustion chamber was also measured. Consequently, it was found that heat loss was increased according to increasing of maximum flame travel distance, but rate of heat loss for heat release during laminar flame propagation was nearly constant. And heat loss depends on heat transfer area which was contacted the wall by burned gas regardless to spark plug location.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.183-191
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• 2013

International network standards for SOLAS ship are composed of instrument network that controls and monitors machine in real time, shipboard control network that controls and monitors system through computer by human and telecommunication network that connects ship and shore. This paper describes development of stack for instrument network protocol complied with NMEA 2000 that is IEC 61162-3 international standards for SOLAS ship and also that of engine room monitoring system using the developed stack. Developed engine room monitoring system is certified by NMEA according to standards that require to pass about 1,600 test procedures.