Study on flow and heat transfer characteristics of LNG in flexible corrugated pipes

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2025-06-25 DOI:10.1016/j.ijthermalsci.2025.110089

Haoping Peng, Lei Huang, Ruichao Tian, Xiaofei Lv, Jiabin Yuan, Yue Liu, Zhiwei Li, Shouwu Xu

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引用次数: 0

Abstract

Flexible corrugated pipes, known for their lightweight and flexibility, play a crucial role in sea transport. This study develops a three-dimensional physical model of flexible corrugated pipes to examine the flow and heat transfer characteristics of LNG across different Reynolds numbers and pipe bending angles using Workbench software. Considering the influence of the local flow resistance coefficient f_j in the bending pipe, the equivalent resistance coefficient fe is proposed to comprehensively study the flow characteristics of LNG in the pipe, and the parameter sensitivity analysis is carried out according to the comprehensive thermal performance index C_PE of the flexible corrugated pipes. Based on the flow field distribution characteristics of corrugated pipes and smooth pipes, the changes of pressure, eddy viscosity, flow resistance coefficient, Nusselt number and comprehensive thermal performance index C_PE under four Reynolds numbers and five bending angles are studied respectively, and the correlation between fe, Nu and C_PE is analyzed. It is observed that the secondary flow and swirl flow will be caused by the fluid entering the corrugated pipes for a certain distance, and the bending wall is beneficial to enhance the degree of fluid disturbance in the corrugated pipes; when the Reynolds number increases, the pressure and eddy viscosity in the corrugated pipes increase linearly, and the convective heat transfer coefficient and the Nusselt number exhibit a linear increase. At the same time, the resistance coefficient fe tends to be stable, the comprehensive thermal performance index C_PE of corrugated pipes decreases gradually. When the bending angle increases from 40° to 120°, the pressure, Nu, f_j and fe in the corrugated pipes increase significantly, and C_PE also increases gradually. Considering the cold preservation requirements for LNG during transportation, bending angles exceeding 80° should be avoided to minimize fluid flow resistance, pipe stress and deformation, while ensuring the safety and economic efficiency of pipeline transport.

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液化天然气在柔性波纹管内流动及传热特性研究

柔性波纹管以其轻便和灵活而闻名，在海上运输中起着至关重要的作用。本研究利用Workbench软件建立了柔性波纹管的三维物理模型，以研究LNG在不同雷诺数和管道弯曲角度下的流动和传热特性。考虑弯曲管道中局部流动阻力系数fj的影响，提出等效阻力系数fe来综合研究LNG在管道中的流动特性，并根据柔性波纹管综合热工性能指标CPE进行参数敏感性分析。基于波纹管和光滑管的流场分布特征，分别研究了四种雷诺数和五种弯曲角度下波纹管的压力、涡流粘度、流阻系数、努塞尔数和综合热性能指标CPE的变化，并分析了fe、Nu与CPE的相关性。观察到流体进入波纹管一定距离后会引起二次流和旋流，弯曲壁有利于增强波纹管内流体扰动程度；随着雷诺数的增加，波纹管内的压力和涡流粘度呈线性增加，对流换热系数和努塞尔数呈线性增加。同时，波纹管的阻力系数fe趋于稳定，波纹管的综合热性能指标CPE逐渐降低。当弯曲角从40°增大到120°时，波纹管内的压力、Nu、fj和fe均显著增大，CPE也逐渐增大。考虑到LNG在运输过程中的冷藏要求，应避免弯曲角度超过80°，以尽量减少流体流动阻力、管道应力和变形，同时保证管道运输的安全性和经济性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.