• Title, Summary, Keyword: 압력변동

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Assessment of the Pressure Transient Inside the Passenger Cabin of High-speed Train Using Computational Fluid Dynamics (전산유체역학을 이용한 고속철도차량 객실 내 압력변동 평가)

  • Kwon, Hyeok-Bin;Nam, Sung-Won;Kwak, Jong-Hyun
    • Journal of the Korean Society for Railway
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    • v.12 no.1
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    • pp.65-71
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    • 2009
  • The pressure transient inside the passenger cabin of high-speed train has been assessed using computational fluid dynamics (CFD) based on the axi-symmetric Navier-Stokes equation. The pressure change inside a train have been calculated using first order difference approximation based on a linear equation between the pressure change ratio inside a train and the pressure difference of inside and outside of the train. The numerical results show that the pressure change inside the new Korean high-seed train passing through a tunnel of Seoul-Busan high-speed line at the speed of 330km/h satisfied well the Korean regulation for pressure change inside a passenger cabin if the train is satisfying the train specification for airtightness required by the regulation.

An experimental study for prediction of the fluctuating pressure induced by a cavitating propeller (캐비티가 발생한 프로펠러의 변동압력 추정을 위한 실험적 연구)

  • K.S. Kim;I.S. Moon;K.Y. Kim;I.H. Song;J.T. Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.36 no.1
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    • pp.47-52
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    • 1999
  • The influence of propeller revolution on measurement of fluctuating pressure is almost minimized in the KRISO cavitation tunnel and the measurement accuracy of fluctuating pressure acting on a flat plate due to a cavitating propeller is improved. The measurement data for Sydney Excess propeller is compared with the measurement results of other research institutes loading to the conclusion that KRISO data is so stable and reasonable. The fluctuating pressure data measured on a model ship and the prototype ship is compared with the data measured on the flat plate. The solid boundary factor, derived from a calculation based on a lifting surface theory, is applied to predict full scale pressure level from the experimental data on the flat plate, showing quite reasonable agreement with full scale data.

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Development of the Design Technology for the Pressurization Equipments of High Speed Train (고속전철용 압력완화장치 설계기술 개발)

  • Yeom, Han-Gil;Park, Seong-Je;Go, Deuk-Yong
    • 연구논문집
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    • pp.21-37
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    • 1998
  • Atmospheric pressure in a tunnel rises in proportion to the square of train’s speed as it enters a tunnel. This pressure difference propagates into the train and cause aural discomfort to the passengers. In order to alleviate the aural discomfort of them. a new ventilation system has been designed and tested. This system controls the charged and discharged by flow rate by detecting the air pressure generated outside and inside of the train. Test to confirm the fundamental performance of the system was carried out. Consequently, this system was found to be able to alleviate the aural discomfort effectively. Application of the system to TGV-K running in the speed range of 350km/h is considered to have good propospect.

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A Study on the Window Glass Pressure for High-speed Train (고속철도차량의 유리창 압력에 관한 연구)

  • Kwon, Hyeok-Bin;Chang, Dae-Sung
    • Journal of the Korean Society for Railway
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    • v.13 no.4
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    • pp.371-375
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    • 2010
  • In order to decide the strength requirement of the window glass for the high-speed train, the pressure change during the passage of the EMU type high-speed train has been numerically simulated. Based on the calculation results, the pressure difference between the inner and outer pressure of the cabin has been calculated to yield the amount of load acting on the window glass of the cabin. To simulate the pressure field generated by the high-speed train passing through the tunnel, computational fluid dynamics based on the axi-symmetric Navier-Stokes equation has been employed. The pressure change inside a train has been calculated using first order difference approximation based on a linear equation between the pressure change ratio inside a train and the pressure difference of inside and outside of the train.

A Study on the Combustion Characteristics in an Aero-Valved Pulsating Combustion System (空氣밸브型 脈動燃燒시스템의 燃燒特性에 관한 硏究)

  • 임광렬;오상헌;최병륜
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.2
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    • pp.328-337
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    • 1988
  • Experimental study was carried out to investigate the combustion characteristics of the hero-valved pulsating combustor with maximum operating capacity of 56kW. The pressure, the ion current, and the temperature fluctuations were simultaneously measured and statistically analyzed to identify the combustion process, the reignition and the mixing process of the reactants. It was found that the pulse combustion process was intermittent and the reignition of the reactants was caused by a direct contact and rapid mixing with the previous hot residuals. The analysis of the measured data indicated that the combustion process consisted of there stages in the combustion chamber; the preheating of the reactants in the vicinity of the air inlet pipe, the explosive combustion in the central region and the afterburning in the vicinity of the tailpipe. Wile the inflow of the fresh air occurred during the negative period of the pressure in the mechanical valved system, it occurred during the rising period of the pressure in the aero-valved system.

A measurement of the pressure fluctuation by using the condenser microphone (콘덴서 마이크로폰을 이용한 압력변동성분의 측정)

  • 윤재건
    • Journal of the korean Society of Automotive Engineers
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    • v.11 no.2
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    • pp.18-23
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    • 1989
  • 본 기고에서는 필자의 경험을 바탕으로 콘덴서 마이크로폰(condenser microphone)을 압력측정 프로우브에 직접 연결하여 압력변동성분을 측정하는 방법을 소개하고, 이 방법의 적용예와 문제점을 검토하고자 한다.

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An Experimental Study on the Pressure Change in the Type of Elevator Hoistways (엘리베이터 승강로 형식별 압력변동에 관한 실험 연구)

  • Kim, Hak-Joong;Kim, Boem-Gyu;Park, Yong-Hwan;Lim, Chae-Hyun
    • Fire Science and Engineering
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    • v.24 no.3
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    • pp.139-144
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    • 2010
  • Recently, evacuation safety of building resident become the major concern, as the building has been higher and more complicated. Many high-rise multi use buildings are under construction in Korea. Required evacuation time using stairway is longer in high-rise buildings, moreover it is impossible for the disabled to evacuate by using stairway. For this reason the study on the effectiveness of using elevator for evacuation is progressing. This study shows the pressure change in various types of hoistway when elevator is moving. Experiments were performed in 4 different types of hoistway, and showed big difference in pressure change between the type of hoistway. The pressure change in single hoistway that have one car is bigger than that in multi hoistway that have multi cars. The results of this study can be used for the study of elevator piston effect as basic data.

A Study of a Correlation between Experiments and Calculations of Pressure Fluctuation on Hull Surface (선체 변동 압력에 관한 실험과 이론의 비교 연구)

  • Moon-Chan Kim;Ki-Sup Kim;In-Haeng Song
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.1
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    • pp.19-26
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    • 1996
  • An experimental and computational study of the pressure fluctuation induced by a propeller on a hull surface was carried out with three ship models and seven model propellers. The fluctuation of pressure on a flat plate was measured at KRISO cavitation tunnel and calculated by a panel and lifting surface method(XForShip code). To extend the measurement data on the flat plate into that on complex hull forms, the correction factor was determined as a ratio of the solid boundary factor(SBF). The computation of pressure fluctuation around complex hull forms was also performed to make the full scale prediction and compared with the corrected experimental data. The calculated values agreed well with the compensated experimental data and it was found that the correction factor was about 0.65-0.7.

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Measurement Uncertainty Analysis for Fluctuating Hull Pressure (선미변동압력 계측시험에서의 불확실성 해석)

  • G.I. Choi
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.4
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    • pp.46-60
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    • 1993
  • Accurate measurements of fluctuating pressure in the cavitation tunnel are necessary to predict vibration and noise intensities in full scale ship. In this paper, the results of an experimental study on fluctuating pressure induced by a cavitating propeller are presented and discussed. Extensive measurements at several propeller revolutions are made using the flat plate to understand controversial problems of the effects of propeller revolution in the cavitation tunnel. The analysis of the uncertainties in experimental measurements and results is used to estimate the errors in uniform flow.

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A Study of Flow Induced Noise for Multilevered Cylinder due to Turbulent Boundary Layer (난류경계층에 의한 다층재질 원통형 실린더의 유체소음 해석 연구)

  • 신구균;홍진숙;이헌곤
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.271-276
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    • 1994
  • 본 연구에서는 외부 호스, 내부 충진유 및 탄성체 핵으로 구성된 다층 재질의 무한히 긴 원통형 실린더가 자유 흐름 중에 있을 때, 유체 유동에 의한 난류 경계층내 벽면 압력 변동(wall pressure fluctuation)이 내부 탄성체 핵의 표면에 미치는 영향을 분석하기 위하여 난류 경계층에 의한 다층 재질의 실린더 내부 압력 변동 해석 이론을 정립하였다. 본 해석 이론에서는 파동 방정식을 이용하여 외부 호스 벽면 압력에 대한 전달 함수를 도출하고, 난류 경계층내 벽면 압력 변동은 Corcos Model을 기초로 하여 Strawderman이 제안한 실험식을 사용하여 추정하였다. 또 이를 바탕으로 자유 흐름 속도 변화등에 따른 실린더 내부 압력변도의 변화를 분석하여 보았다.

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