为了揭示液化天然气(Liquefied Natural Gas，LNG) 船内低温蝶阀的蝶板结构对流动特性的影响，基于计算流体力学（Computational Fluid Dynamics，CFD)技术数值模拟了两种不同的蝶板结构在90°~10°不同开度下对阀门流动特性的影响，重点对比分析各开度下的阀门流量系数。结果表明：开度在90°~20°范围内龟背式蝶板会压缩流通面积，使局部流速和湍流强度高于全轴式蝶板，导致压损更大、流量系数更低，且随着开度减小，流量系数差距逐步增大；在开度10°时，由于龟背流线型结构有利于降低开口处压力损失，龟背式蝶阀的流量系数高于全轴式蝶阀。考虑到LNG船用蝶阀在工作时多为全开状态，全轴式蝶阀比龟背式蝶阀拥有更好的流通性能。

To reveal the influence of the butterfly disc structure of low temperature butterfly valve on the flow behavior in liquefied natural gas (LNG) ship，two kinds of butterfly disc structures at different opening degrees of 90° to 10° were numerically simulated based on computational fluid dynamics (CFD) technology，and the flow coefficient at each opening degree was emphatically compared and analyzed. The results show that the turtleback disc will compress the flow area at the opening degrees between 90° and 20°，which results in higher local velocity and turbulence intensity than that in the fullshaft disc，leading to larger pressure loss and lower flow coefficient. As the opening degree decreases，the flow coefficient gap increases gradually; when the opening degree is 10°，the flow coefficient of the turtleback butterfly valve is higher than that of the fullshaft type，due to the weakening of the pressure loss at the opening which is mainly influenced by the streamlined structure of the turtleback. Considering that the LNG ship butterfly valve is mostly fully open in use，the fullshaft butterfly valve has better flow performance than the turtleback one.

TH137