Abstract

Liquefied natural gas (LNG) is a clean energy source that shows great potential for further development. In the production and transportation process of LNG, heat exchanger is an essential device that conducts the liquefaction and vaporization operations. With the booming development of floating LNG (FLNG) technology, higher requirements have been put forward for heat exchangers due to the limited space and rolling conditions. Printed circuit heat exchanger (PCHE), as a typical micro-channel heat exchanger, is considered an ideal candidate for floating storage and regasification unit (FSRU) due to preeminent compactness and efficiency. In this study, a three-dimensional model of sinusoidal channel-based printed circuit LNG vaporizer is established. The thermal–hydraulic and entropy generation characteristics of the vaporizer with various waviness factors, including the amplitude and wavelength, are numerically investigated. The results indicate that larger amplitude or smaller wavelength results in the heat transfer augmentation with greater pressure drop and minor overall entropy generation. As the secondary flows with boundary layer destructions caused by sinusoidal channel structures enhance the local heat transfer, the entropy generation concentrates at the near-wall region. For a sinusoidal channeled printed circuit LNG vaporizer, moderate amplitude and wavelength are more reasonable to obtain better comprehensive performance, and the thermal–hydraulic performance and irreversible energy loss should be considered simultaneously.

Graphical abstract

中文翻译：

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正弦通道式印制电路液化天然气气化器的热工性能和熵产生特性的研究

摘要

液化天然气（LNG）是一种清洁能源，具有进一步发展的巨大潜力。在液化天然气的生产和运输过程中，热交换器是进行液化和汽化操作的必不可少的设备。随着浮动液化天然气（FLNG）技术的蓬勃发展，由于空间和滚动条件的限制，对热交换器提出了更高的要求。作为一种典型的微通道换热器，印刷电路换热器（PCHE）由于出色的紧凑性和效率，被认为是浮动存储和再气化装置（FSRU）的理想选择。在这项研究中，建立了基于正弦通道的印刷电路板LNG汽化器的三维模型。数值研究了具有各种波纹度因素（包括幅度和波长）的蒸发器的热工和熵产特性。结果表明，较大的振幅或较小的波长会导致传热增加，压力降更大，总的熵产生较小。当由正弦形通道结构引起的带有边界层破坏的二次流增强了局部传热时，熵的产生就集中在近壁区域。对于正弦通道印刷电路板LNG气化器，适度的振幅和波长更合理，以获得更好的综合性能，并且应同时考虑热工性能和不可逆能量损失。进行了数值研究。结果表明，较大的振幅或较小的波长会导致传热增加，且压降更大，总的熵产生较小。当由正弦形通道结构引起的带有边界层破坏的二次流增强了局部传热时，熵的产生就集中在近壁区域。对于正弦通道印刷电路板LNG气化器，适度的振幅和波长更合理，以获得更好的综合性能，并且应同时考虑热工性能和不可逆能量损失。进行了数值研究。结果表明，较大的振幅或较小的波长会导致传热增加，压力降更大，总的熵产生较小。当由正弦形通道结构引起的带有边界层破坏的二次流增强了局部传热时，熵的产生就集中在近壁区域。对于正弦通道印刷电路板LNG气化器，适度的振幅和波长更合理，以获得更好的综合性能，并且应同时考虑热工性能和不可逆能量损失。当由正弦形通道结构引起的带有边界层破坏的二次流增强了局部传热时，熵的产生就集中在近壁区域。对于正弦通道印刷电路板LNG气化器，适度的振幅和波长更合理，以获得更好的综合性能，并且应同时考虑热工性能和不可逆能量损失。当由正弦形通道结构引起的带有边界层破坏的二次流增强了局部传热时，熵的产生就集中在近壁区域。对于正弦通道印刷电路板LNG气化器，适度的振幅和波长更合理，以获得更好的综合性能，并且应同时考虑热工性能和不可逆能量损失。

图形概要