扭曲螺旋管内LNG的传热与流动特性研究

Research on heat transfer and flow characteristics of LNG in twisted spiral tube

采用数值分析方法,分别对液化天然气(LNG)在扭曲椭圆管和扭曲扁管内发生相变时的传热和流动特性进行了研究,分析了管道长短轴之比和雷诺数对管道换热性能的影响。结果表明,扭曲管道内流体流动产生的二次流强化了管道的传热性能。扭曲椭圆管道的综合性能系数PEC值均大于1,其换热性能优于相同条件下的圆管;扭曲扁管的长短轴之比小于2时,在低雷诺数时的PEC值小于1,此时扭曲扁管的换热性能不如相同条件下的圆管。在管道长短轴之比相同时,相同条件下扭曲椭圆管的综合性能优于扭曲扁管。

The heat transfer and flow characteristics of liquefied natural gas(LNG)during phase change in twisted elliptic tubes and twisted flat tubes were studied by numerical analysis.The effects of the ratio of major axis to minor axis and Reynolds number on the heat transfer performance of the tubes were analyzed.The results show that the secondary flow generated by the fluid flow in the twisted tube enhances the heat transfer performance of the tube.The comprehensive coefficient of performance(PEC)of the twisted elliptical tube is greater than 1,and its heat transfer performance is better than that of the round tube under the same conditions.When the ratio of long axis to short axis of twisted flat tube is less than 2,the PEC at low Reynolds number is less than 1,and the heat transfer performance of twisted flat tube is not as good as that of round tube under the same conditions.At the same ratio of long axis to short axis,the overall performance of twisted elliptical tube is better than that of twisted flat tube under the same conditions.