波纹管结构尺寸及内芯对管内液氮流动的影响  

Effect of different geometries of bellows with/without insert on internal liquid nitrogen flow

作　　者：周绍华[1] 闫畅迪 黄永华[1,2] 

机构地区：[1]上海交通大学制冷与低温工程研究所,上海200240 [2]上海市低温技术与测试应用服务平台,上海200240

出　　处：《哈尔滨工业大学学报》2018年第1期107-113,共7页Journal of Harbin Institute of Technology

基　　金：上海交大航天先进技术联合研究中心技术创新项目(USCAST2016-32);国家自然科学基金(51676118)

摘　　要：为深入探讨更大结构尺寸范围内波纹管的液氮流动阻力特性,以量纲一的波高内径比和波距波高比为变量,通过建立波纹管内液氮流动的CFD仿真模型,考察较宽范围内波高内径比、波距波高比以及管内是否插入内芯情况下,达西摩擦因子在不同雷诺数下的变化规律,并与实验数据进行对比验证.结果表明:波纹管内流体进入波节形成漩涡是导致波纹管阻力增大的主要原因;当波高内径比和波距波高比不变时,仅改变波纹管的内径对达西摩擦因子几乎没有影响;内芯波纹管的内芯直径越大,达西摩擦因子越小;而内芯直径越小,其达西摩擦因子越接近空心波纹管.仿真结果与实验数据吻合良好.To further discover the flow resistance characteristics of liquid nitrogen in bellows in wider application range,dimensionless variables namely the ratio of wave-height over bellows-diameter（e/d） and the ratio of wavepitch over wave-height（p/e） are introduced. CFD modeling has been conducted on the behaviors of both pressure drop and Darcy friction factor（f） at different geometries of the bellows,either with or without an insert. Effects on the f by different Reynolds numbers at certain ratios e/d or p/e in wide ranges were investigated. The results shows that the vortex forming inside the bellows trough is the main cause of the flow resistance increment. When the e/d and p/e remain unchanged,changing of the inner diameter of the bellows has little influence on the friction factor. If a rod is inserted into the bellows,the larger the rod diameter,the smaller the Darcy friction factor. When the diameter of the insert reduces to zero,the friction factor approaches that of the hollow bellows,which is consistent with the experimental results.

关 键 词：波纹管 CFD仿真 波纹管阻力 达西摩擦因子 内芯 

分 类 号：TB661[一般工业技术—制冷工程]