• Title/Summary/Keyword: Valve noise

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A Study on Design of Diffuser Sliencer in Boiler (보일러용 디퓨저 소음기 설계에 관한 연구)

  • 남경훈;박실룡;이덕주;김재욱
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.271-278
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    • 1997

  • The flow of steam through a safety valve vent pipe system in the boiler has been analyzed to provide a design basis of diffuser silencer for attenuating shock-shell and jet noise. Numerical analysis to estimate inner fluid of silencer and noise propagation outside silencer are performed. The distribution curve of fluid information to provide average values about inner fluid of silencer is presented by theoretical analysis.

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Numerical investigation into flow noise source of a convergent-divergent nozzle in high pressure pipe system using wavenumber-frequency analysis (파수-주파수 분석을 통한 고압 배관 내 수축 확장 노즐의 유동 소음원에 대한 수치적 연구)

  • Ku, Garam;Lee, Songjune;Kim, Kuksu;Cheong, Cheolung
    • The Journal of the Acoustical Society of Korea
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    • v.36 no.5
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    • pp.314-320
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    • 2017

  • A pressure relief valve is generally used to prevent piping systems from being broken due to high pressure gas flows. However, the sudden pressure drop caused by the pressure relief valve produces high acoustic energy which propagates in the form of compressible acoustic waves in the pipe and sometimes causes severe vibration of the pipe structure, thereby resulting in its failure. In this study, internal aerodynamic noise due to valve flow is estimated for a simple contraction-expansion pipe by combining the LES (Large-Eddy Simulation) technique with the wavenumber-frequency analysis, which allows the decomposition of fluctuating pressure into incompressible hydrodynamic pressure and compressible acoustic pressure. In order to increase the convergence, the steady Reynolds-Averaged Navier-Stokes equations are numerically solved. And then, for the unsteady flow analysis with high accuracy, the unsteady LES is performed with the steady result as the initial value. The wavenumber-frequency analysis is finally performed using the unsteady flow simulation results. The wavenumber-frequency analysis is shown to separate the compressible pressure fluctuation in the flow field from the incompressible one. This result can provide the accurate information for the source causing so-called acoustic-induced-vibration of a piping system.

  • https://doi.org/10.7776/ASK.2017.36.5.314 인용 PDF KSCI

A Numerical Study of New Vehicle Hydraulic Lift Activation by a Magneto-rheological Valve System for Precise Position Control (정밀 위치 제어를 위해 MR 밸브 시스템을 활용한 차량 유압 리프트에 대한 수치해석적 고찰)

  • Lee, TaeHoon;Park, Jhin-Ha;Choi, Seung-Bok;Shin, Cheol-Soo;Choi, Ji-Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.1
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    • pp.28-35
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    • 2017

  • Recently, conventional hydraulic car lift systems face the technological limitations due to a lack of height control. The demand for height controllability is required in many tasks such as wheel alignment, and requires compensation for the structural deformation of the lift caused by irregular load distribution. In order to resolve this limitation of the conventional car lift, in this work, a new type of a hydraulic vehicle lift using a magneto-rheological (MR) valve system is proposed and analyzed. Firstly, the dynamic model of vehicle lift is formulated to evaluate control performance; subsequently, an MR valve is designed to obtain the desired pressure drop required in the car lift. Next, a proportional-integral-derivative (PID) controller is formulated to achieve accurate control of the lifting height and then computer simulations are undertaken to show accurate height control performances of the proposed new car lift system.

  • https://doi.org/10.5050/KSNVE.2017.27.1.028 인용 PDF KSCI