中文摘要：

本文采用数值模拟的方法研究了以甲烷为代表的超临界液化天然气（Liquefiednaturalgas简称LNG）在竖直管内的流动与换热特性。通过研究不同结构换热管下甲烷的换热性能，得到了不同结构下甲烷超临界管内流动的换热关联式。结果表明在研究范围内，作为一种工程方法对于普通圆管以及内插螺旋扰流片的翅片管内超临界甲烷的流动，其换热系数可基于Dittus—Boelter公式及引入修正系数进行计算。采用甲烷物性与采用LNG物性所得数值模拟结果偏差不大。

英文摘要：

The flow and heat transfer characteristics of supercritical liquefied natural gas （LNG） in a vertical tube was numerically investigated by taking methane as an example. The numerically predicted heat transfer coefficients in tubes of various structures show that as an engineering design method the heat transfer coefficients of supercritical methane in the vertical circular smooth tube and finned tube with a in-tube spiral spoiler can be calculated according to the Dittus-Boelter formula in conjunction with some modified coefficients within the range studied. There is a minor deviation between the results of numerical simulation of LNG and methane.