在液化天然气动力船舶中，超临界液化天然气在使用前需要进行气化。超临界LNG的气化是一个拟相变过程。本研究对超临界LNG在拟相变过程中的局部流动和传热性能进行数值研究，主要目的是揭示在不同截面形状通道内浮力对局部流动和传热性能的影响。研究发现，浮力因子的大小受截面形状影响不大。另一方面，浮力对传热性能的影响集中在类液区和拟临界区。二次流是由于浮力和密度差异的影响而产生的。流体的分布及二次流受到通道形状及浮力的影响从而影响传热性能。通常，二次流的存在提高了通道壁面和相邻流体间的传热性能。然而，由于浮力的原因，低密度、高温流体聚集在通道顶部，导致局部传热性能恶化。因为通道截面形状的不同，导致湍动能及定压比热的分布不相同，从而造成传热性能存在差异。
In LNG powered ships, supercritical liquefied natural gas (LNG) needs to be gasified before use. The gasification of supercritical LNG is a pseudophase transition process. This study presents a numerical investigation of the local flow and heat transfer performance of supercritical LNG in the pseudophase transition. The main objective is to reveal the effect of buoyancy on the local flow and heat transfer performance in channels with different cross-section shapes. It was found that the cross-section shape has a little impact on the buoyancy factor. On the other hand, the effect of buoyancy on the heat transfer performance is concentrated in the liquid-like and pseudo-critical regions. The secondary flow was generated due to the influence of buoyancy and density differences. The distribution and secondary flow of the fluid are affected by the cross-section shape and buoyancy, which affects the heat transfer performance. In general, the secondary flow improves the heat transfer performance between the channel wall and the adjacent fluid. However, due to buoyancy, low-density and high-temperature fluids accumulate at the top of the channel, resulting in deterioration of local heat transfer performance. Because of the different cross-sectional shape of the channel, the distribution of turbulent kinetic energy and the specific heat at constant pressure is different, resulting in differences in heat transfer performance.
2024,46(5): 6-13 收稿日期：2023-03-13
DOI：10.3404/j.issn.1672-7649.2024.05.002
分类号：TK124
基金项目：江苏省海洋与渔业科技创新与推广项目 (HY2017-8)
作者简介：陈正超(1996-),男,硕士研究生,研究方向为流体仿真及强化换热
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