• Title/Summary/Keyword: 슬로싱

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LNG 슬로싱 현상을 고려한 FPSO와 LNG운반선의 동적거동에 관한 연구

  • Lee, Seung-Jae;Go, Jeong-Min;Gong, Ji-Hun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2011.11a
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    • pp.5-7
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    • 2011
  • LNG 운반선이 대형화 됨에 따라 슬로싱의 동적거동에 대한 영향에 대한 관심이 증가하고 있다. 본 연구에서는 시간영역에서 슬로싱 현상과 FPSO와 LNG운반선의 거동을 동적으로 연성하여, LNG 슬로싱이 두 부유체의 global performance에 미치는 영향을 시간영역에서 시뮬레이션하였다.

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Numerical Study on Effects of Velocity Profile of Liquid Container on Sloshing (액체 용기의 속도 프로파일이 슬로싱에 미치는 영향 해석)

  • Kim, Dongjoo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.5
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    • pp.313-319
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    • 2016
  • It is very important to understand and control the sloshing in a liquid container that is partially filled with liquid. Previous studies focused primarily on the sloshing and resonance caused by sinusoidal excitations, while the present study focuses on understanding and suppressing sloshing in a container that moves rapidly from a given point to another in industrial applications. To achieve this, we first numerically predict the two-phase flow induced by the horizontal movement of a rectangular container. Then we analyze the effects of container-velocity profile (in particular acceleration/deceleration duration) on sloshing. Results show that sloshing is significantly suppressed when the acceleration/deceleration duration is a multiple of the 1st-mode natural period of sloshing.

Measuring Technique for Sloshing Phenomenon of vibrated liquid Storage Tank (가진을 받는 액체 저장탱크 내의 슬로싱 측정 기법 연구)

  • 윤성호;박기진;권호용
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2002.04a
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    • pp.80-81
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    • 2002
  • 비행체의 액체 저장탱크에서의 슬로싱 현상은 비행체의 조정 안정성 상실은 물론 구조적인 파손이 발생하여 인명 및 재정 손실이 초래 될 수 있다. 또한 최근 대형 선박에서의 액체 저장탱크에서도 슬로싱 문제는 주요한 관심사로 되어 있다. 선진기술국에서는 이러한 슬로싱 문제를 해결하기 위해 많은 관심을 쏟아 왔으나 국내에서는 체계적인 연구가 미흡한 실정이다.

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Design of Tank Velocity Based on Multi-Mode Natural Frequencies for Suppression of Sloshing (다모드 고유 진동수를 고려한 슬로싱 억제용 용기 속도의 설계)

  • Sim, Taegwon;Kim, Dongjoo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.5
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    • pp.311-320
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    • 2017
  • Suppression of sloshing is essential to achieve fast transportation and stable maneuvering of tanks partially filled with liquid. In this study, numerical simulations are performed to investigate the effects of the acceleration magnitude and the acceleration duration of triangular velocity profiles on sloshing when a rectangular tank moves horizontally. We previously reported, based on only the first natural mode, that sloshing is significantly suppressed when the acceleration duration equals the first natural period of sloshing. On the other hand, the present CFD simulations find the best acceleration duration for minimum sloshing and explains the results considering higher modes as well as the first mode. We also perform the analysis using an equivalent model based on masses and springs, and evaluate its accuracy by comparing it with the CFD simulation results.

Simulation of Membrane Sloshing Tank by Using MPS (입자법을 이용한 멤브레인 타입 슬로싱 시뮬레이션)

  • Kim, Kyung Sung
    • Journal of the Korea Convergence Society
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    • v.10 no.10
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    • pp.117-122
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    • 2019
  • In the field of fluid dynamics, the sloshing effects are most common and significant problem. It is usually appeared in the tank filled with fluid which is on the main structure, thus, sloshing effects and its impact load may affect to entire system. For the sloshing effects analysis, impact loads due to tank motion is generally investigated theocratically, experimentally and numerically. The difficulty of sloshing phenomenon is non-linearity induced by large deformation at the free-surface. In this regard, it is well known issue that the repeatability on the sloshing problems is very low. In this study, moving particle semi-implicit method was employed to simulate sloshing problem and then the results were compared with corresponding experiments captured by high accuracy high speed camera. The results from numerical simulation was compared to experimental results.

Numerical Simulation of Sloshing Test for Fuel Tank of Rotorcraft (회전익항공기용 연료탱크 슬로싱 시험 수치해석)

  • Kim, Hyun-Gi;Kim, Sung Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.687-693
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    • 2016
  • The rapid turning and acceleration movement of a rotorcraft leads to a sloshing phenomenon in the fuel tank. Sloshing caused by rapid movement can affect the internal components by creating an excessive load. In severe situations, the resulting damage to the internal components and pipes can also lead to the tearing of the fuel tank itself. Therefore, to improve the survivability of the crew, the internal components of the fuel tank must be designed to retain their structural soundness during the sloshing phenomenon. In order to accomplish this, the sloshing load acting on the components first needs to be determined. This paper investigates the sloshing load applied to the internal components by performing numerical analysis for rotary-wing aircraft fuel tanks in the sloshing test. Fluid-Structural Interaction (FSI) analysis based on smoothed particle hydrodynamics (SPH) is conducted and the conditions specified in the US military standard (MIL-DTL-27422D) are employed for the numerical simulation. Based on this numerical simulation, by analyzing the load applied to the internal components of the fuel tank due to the sloshing phenomenon, the possibility of obtaining the design data by numerical analysis is examined.

Analysis of Sloshing Frequency Response in Rectangular Fuel-Storage Tank (사각형 연료탱크 내 슬로싱 주파수 응답 해석)

  • 조진래;이홍우;하세윤;박태학;이우용
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.1
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    • pp.95-104
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    • 2003
  • This paper deals with the analytic and FEM analyses of sloshing frequency response of incompressible, invicid and irrotational flow in two dimensional rectangular tank. We use Laplace equation based on potential theory as governing equation. For small amplitude sloshing motion, the linearized free surface condition was applied and the analytic solution as obtained by the separation of variables. To simulate the effect of the energy dissipation due to viscous damping, artificial viscous coefficient is introduced and the divergence of response at resonance frequencies may be avoided by this coefficient. This problem was solved by FEM using 9-node elements in order to predict the maximum amplitude of sloshing response. Numerical results of free surface height, fluid pressure and fluid force show good agreement with those by analytic solution. After verifying the test FEM program, we analyze the frequency response characteristics of sloshing to the fluid height.

A Study on the Sloshing Reduction of a Cargo Fuel Tank with Baffle (배플을 적용한 Cargo용 연료탱크 내부의 슬로싱 저감 연구)

  • Yoon, Bo-Hyun;Yoon, Jun-Kyu;Lim, Jong-Han
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.8
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    • pp.1074-1083
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    • 2010
  • Recently sloshing that fluid in fuel tank is undulating by the external force during motion of automobile, ship and aircraft is greatly affecting by damaging the inside of structure. It's most important to precisely analyze the behavior of fluid by computational fluid dynamics for minimizing the effect of sloshing for the loaded fuel. This study characterized volume of fluid and pressure according to the length and number of vertical baffle and horizontal baffle in fuel tank for Kia Frontier cargo and analyzed for reduction of sloshing during driving on corner and hill by using ADINA-CFD. As a result of analysis, the optimum length for sloshing reduction shows 0.19 m for vertical baffle and 0.08 m for horizontal baffle. And it shows that vertical baffle is better for the reduction effect of sloshing during driving on corners, on the other hand, horizontal baffle is effective and stable during driving on hills.

The Study of 1-Way FSI for Strength Assessment of LNG Cargo Containment System (1-way FSI 기법에 의한 LNG 운반선 화물창의 강도평가에 관한 연구)

  • Lee, Sung-Je;Yang, Yong-Sik;Kim, Sung-Chan;Lee, Jang-Hyun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.527-530
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    • 2011
  • 전 세계적인 LNG 수요 증가에 따라 LNG 운반선의 대형화 및 극한 환경의 항로 선택이 불가피해지고 있다. 이러한 상황에서 LNG의 슬로싱 현상에 따른 화물창의 구조적 안정성 여부가 큰 이슈거리로 떠오르고 있다. 슬로싱 현상에 의한 구조 안전성을 평가하는 가장 이상적인 방법은 유체 영역과 탱크의 복합적인 상호 작용을 완벽하게 구현하는 것이다. 하지만 과도한 계산 시간과 결과의 정확성이 확보되지 못한 상황에서 LNG 운반선 화물창의 안전성 평가에 적용하기에는 문제가 있다. 많은 연구 단체에서는 불규칙적인 슬로싱 압력 신호를 삼각파 등의 형태로 이상화하여 구조해석에 적용하고 있지만 이 또한 유체의 압축성 및 비선형성을 고려하는데 한계를 드러내고 있다. 본 연구에서는 슬로싱 하중을 받는 구조의 안전성을 평가함에 있어 쌍방향(2-way) FSI(Fluid-Structure Interaction)의 과도한 해석 시간 및 수렴의 어려움을 보안하고 유체의 비선형성을 고려할 수 있는 단 방향(1-way) FSI 기법을 이용하는 절차를 제안하고자 한다.

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Study on Sloshing Behaviors in Liquid Storage Tank with Rectangular Cross Section (사각단면 액체저장탱크에서의 슬로싱 거동 연구)

  • 윤성호;이은동;박기진
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1087-1090
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    • 2003
  • In this study, experimental procedures were suggested to investigate the sloshing behavior of a liquid storage tank subjected to inevitably external vibrating conditions. For this purpose. liquid storage tank with rectangular cross section was made of an acrylic resin for the visualization of liquid fluctuation. A specially designed vibrator was used to provide a specified vibrating condition to the liquid storage tank. Extrapolation technique was applied to determine sloshing natural frequency by using various sloshing frequencies at each vibrating displacement and liquid contents at a fixed vibrating frequency. Sloshing mode was also determined from continuous images or liquid fluctuation captured from a video camera. In addition, change in the height of the liquid free surface was measured by using a floating target and a laser displacement sensor. It is found that the suggested method can be applicable to identify the sloshing behavior of liquid storage tank with rectangular cross section.

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