[1] Yan Yan, Xu Zhan, Wei Wei, Ni Zhonghua, et al. Numerical investigation of liquid sloshing in FLNG membranetanks with various bottom slopes [J]. Journal of Southeast University (English Edition), 2020, 36 (3): 292-300. [doi:10.3969/j.issn.1003-7985.2020.03.007]

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Numerical investigation of liquid sloshing in FLNG membranetanks with various bottom slopes()

液化天然气船用储罐形貌对流体晃动特性影响的数值分析

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Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]

Volumn:

36

Issue:

2020 03

Page:

292-300

Research Field:

Energy and Power Engineering

Publishing date:

2020-09-20

Info

Title:

Numerical investigation of liquid sloshing in FLNG membranetanks with various bottom slopes

液化天然气船用储罐形貌对流体晃动特性影响的数值分析

Author(s):

Yan Yan¹;  Xu Zhan¹;  Wei Wei²;  Ni Zhonghua¹;  Sun Dongke¹

¹ School of Mechanical and Engineering, Southeast University, Nanjing 211189, China
² Zhangjiagang Research Institute of Hydrogen Energy Co. Ltd., Zhangjiagang 215637, China

严岩¹;  徐展¹;  魏蔚²;  倪中华¹;  孙东科¹

¹东南大学机械工程学院, 南京 211189; ²张家港氢云新能源研究院有限公司, 张家港 215637

Keywords:

liquid sloshing;  natural frequency;  sloped tank bottom;  volume-of-fluid method

液体晃动;  固有频率;  储罐底板斜度;  流体体积法

PACS:

TE835

DOI:

10.3969/j.issn.1003-7985.2020.03.007

Abstract:

To analyze the bottom slope’s effect on the sloshing liquid in floating liquefied natural gas(FLNG)membrane tanks, a simulation model is built and applied to describe the liquid behavior in a sloshing container. The free surface motion is simulated by the volume-of-fluid method and the standard k-ε turbulence model. Experimental data and numerical results from references are used to validate the accuracy of the proposed simulation model. To study the influence of the sloped bottom on the liquid sloshing, different slope sizes and filling ratios are numerically simulated at the lowest natural frequency. The results reveal that the natural frequency can be determined by the average peak values of hydrodynamic parameters. The natural frequency and pressure loading on the tank walls decrease with the increase in the slope size. The peak pressure on the wall decreases by 5.45 kPa with the increase in the slope ratio from 5% to 20%. However, the relationship between the peak pressure and slope ratio is more significant with lower filling rates. Liquid behavior is more stable and independent with the change of the slope structure at a high filling rate(60%). The results of numerical simulation and modeling are expected to provide reference data for the design and operation of the FLNG system.

为了分析浮式液化天然气平台薄膜式储罐底部斜坡对流体晃动的影响规律, 建立了仿真模型用于描述晃动储罐内的流体行为.流体自由液面运动通过流体体积法和k-ε湍流模型进行模拟, 利用文献中的实验数据和仿真结果对该模拟的准确性进行验证.为了研究底部斜坡对流体晃动的影响, 对不同斜坡尺寸、填充率以及储罐低阶固有频率下的流体晃动过程进行了仿真模拟.结果显示, 固有频率可由水力参数的平均峰值决定, 固有频率和储罐壁面压力载荷随着斜坡尺寸的增大而减小, 当斜坡占比从5%增加到20%, 壁面峰值压力下降了5.45 kPa.但该壁面峰值压力的变化只在填充率较低时明显, 当填充率较高, 如60%时, 流体运动特性稳定, 受斜坡结构改变的影响很小.流体仿真建模与分析结果对薄膜式液化天然气储罐的优化设计和运行提供了数据支撑.

References:

[1] Faltinsen O M, Timokha A N. Sloshing [M]. Cambridge, UK: Cambridge University Press, 2009.
[2] Evans D V. The wide-spacing approximation applied to multiple scattering and sloshing problems[J].Journal of Fluid Mechanics, 1990, 210: 647-658. DOI:10.1017/s0022112090001434.
[3] Yakimov A S. Method of solution of nonlinear boundary problems[M]//Analytical Solution Methods for Boundary Value Problems. London: Academic Press, 2016: 41-85. DOI:10.1016/b978-0-12-804289-2.00003-x.
[4] Dinvay E, Kuznetsov N. Modified babenko’s equation for periodic gravity waves on water of finite depth[J]. The Quarterly Journal of Mechanics and Applied Mathematics, 2019, 72(4): 415-428. DOI:10.1093/qjmam/hbz011.
[5] Chen H C, Taylor R L. Vibration analysis of fluid-solid systems using a finite element displacement formulation[J].International Journal for Numerical Methods in Engineering, 1990, 29(4): 683-698. DOI:10.1002/nme.1620290402.
[6] Hu J, Guo L, Sun S L. Numerical simulation of the potential flow around a submerged hydrofoil with fully nonlinear free-surface conditions[J]. Journal of Coastal Research, 2018, 341: 238-252. DOI:10.2112/jcoastres-d-16-00153.1.
[7] Zhang A M, Sun P N, Ming F R, et al. Smoothed particle hydrodynamics and its applications in fluid-structure interactions[J].Journal of Hydrodynamics, 2017, 29(2): 187-216. DOI:10.1016/s1001-6058(16)60730-8.
[8] Shamsoddini R, Abolpur B. Investigation of the effects of baffles on the shallow water sloshing in A rectangular tank using A 2D turbulent ISPH method[J]. China Ocean Engineering, 2019, 33(1): 94-102. DOI:10.1007/s13344-019-0010-z.
[9] Battaglia L, Cruchaga M, Storti M, et al. Numerical modelling of 3D sloshing experiments in rectangular tanks[J]. Applied Mathematical Modelling, 2018, 59: 357-378. DOI:10.1016/j.apm.2018.01.033.
[10] Saripilli J R, Sen D. Numerical studies on effects of slosh coupling on ship motions and derived slosh loads[J]. Applied Ocean Research, 2018, 76: 71-87. DOI:10.1016/j.apor.2018.04.009.
[11] Kim Y. Numerical simulation of sloshing flows with impact load[J].Applied Ocean Research, 2001, 23(1): 53-62. DOI:10.1016/s0141-1187(00)00021-3.
[12] Lu L, Jiang S C, Zhao M, et al. Two-dimensional viscous numerical simulation of liquid sloshing in rectangular tank with/without baffles and comparison with potential flow solutions[J].Ocean Engineering, 2015, 108: 662-677. DOI:10.1016/j.oceaneng.2015.08.060.
[13] Li Q, Zhuang Y, Wan D C. Study on sloshing coupled motion of FLNG section in waves based on CFD method[J]. Chinese Journal of Hydrodynamics, 2019, 34(1): 28-38. DOI:10.16076/j.cnki.cjhd.2019.01.004. (in Chinese)
[14] Kawahashi T, Arai M, Wang X, et al. A study on the coupling effect between sloshing and motion of FLNG with partially filled tanks[J]. Journal of Marine Science and Technology, 2019, 24(3): 917-929. DOI:10.1007/s00773-018-0596-5.
[15] Tezdogan T, Demirel Y K, Kellett P, et al. Full-scale unsteady RANS CFD simulations of ship behaviour and performance in head seas due to slow steaming[J]. Ocean Engineering, 2015, 97: 186-206. DOI:10.1016/j.oceaneng.2015.01.011.
[16] Fu J, Tang Y, Li J X, et al. Four kinds of the two-equation turbulence model’s research on flow field simulation performance of DPF’s porous media and swirl-type regeneration burner[J]. Applied Thermal Engineering, 2016, 93: 397-404. DOI:10.1016/j.applthermaleng.2015.09.116.
[17] Graczyk M, Berget K, Allers J. Experimental investigation of invar edge effect in membrane LNG tanks[J]. Journal of Offshore Mechanics and Arctic Engineering, 2012, 134(3): 031801-1-031801-7. DOI:10.1115/1.4005183.
[18] Rudman M, Cleary P W. Modelling sloshing in LNG tanks [C]//Seventh International Conference on CFD in the Minerals and Process Industries. Melbourne, Australia, 2009: 1-6.
[19] Johnson M C, Savage B M. Physical andnumerical comparison of flow over ogee spillway in the presence of tailwater[J]. Journal of Hydraulic Engineering, 2006, 132(12): 1353-1357. DOI:10.1061/(asce)0733-9429(2006)132:12(1353).
[20] Lee S E, Paik J K. Pressure-impulse diagram of the FLNG tanks under sloshing loads [J].The International Journal of Marine Science and Technology, 2018, 160(A2): 109-119. DOI:10.3940/rina.ijme.2018.a2.436.
[21] Chen Z, Zong Z, Li H T, et al. An investigation into the pressure on solid walls in 2D sloshing using SPH method[J]. Ocean Engineering, 2013, 59: 129-141. DOI:10.1016/j.oceaneng.2012.12.013.
[22] Zhao D, Hu Z, Chen G. Coupling effects of liquid loading vessels in the floating liquefied natural gas system [J]. Journal of Shanghai Jiaotong University, 2019, 53(5): 540-548.(in Chinese)
[23] Li Y L, Zhu R C, Miao G P, et al. Simulation of ship motions coupled with tank sloshing in time domain based on OpenFOAM[J]. Journal of Ship Mechanics, 2012, 16(7): 750-758.(in Chinese)
[24] Yan Y, Ni Z H, Liu X J, et al. Numerical study of bottom shape effect on pressure performance in a sloshing FLNG membrane tank[C]//Proceedings of ASME Conference on ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. Trondheim, Norway, 2017. DOI:10.1115/OMAE2017-61008.

Memo

Memo:

Biographies: Yan Yan(1988—), male, doctor, lecturer; Ni Zhonghua(corresponding author), male, doctor, professor, nzh2003@seu.edu.cn.
Foundation items: The National Natural Science Foundation of China(No.51905093), the Natural Science Foundation of Jiangsu Province for Young Scholars(No.BK20180392).
Citation: Yan Yan, Xu Zhan, Wei Wei, et al.Numerical investigation of liquid sloshing in FLNG membrane tanks with various bottom slopes[J].Journal of Southeast University(English Edition), 2020, 36(3):292-300.DOI:10.3969/j.issn.1003-7985.2020.03.007.

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