螺旋型波纹管流阻测量系统研制及液氮压降测量

超导电缆芯通常内嵌于真空绝热波纹管并被管内低温流动介质冷却和保护。螺旋型波纹管因一次成型制作长度上的优势更适合于大长度超导电缆应用。设计并搭建了螺旋型波纹管液氮流动压降特性实验台,不仅可以方便地更换被测波纹管样品,而且允许插入不同规格的线芯模拟物。利用该实验台测量了液氮流量1~9 L/min区间内不同规格(通径11~15 mm)螺旋型波纹管插入4 mm线芯后的流动压降特性。实验结果验证了三维波纹管压降损失数值模型的准确性。同时,通过进行不同尺寸波纹管实验,发现尺寸变化对摩擦因子变化规律的影响不明显,这为通过该实验台获得小管径实验数据用于指导大管径实际应用波纹管设计提供了理论基础。

Development of flow resistance measurement system for helically corrugated pipes and its test on liquid nitrogen flow loss

Bellows are utilized for containing superconducting cables and liquid nitrogen as the coolant.Helical bellows are more suitable for large length superconducting cables because of their advantages in manufacturing length.However,experimental research is not sufficient on the flow behavior of liquid nitrogen in helically corrugated pipes with core.This study designed and built an experimental system for testing flow loss characteristics of helically corrugated pipes.Not only the bellows sample but also the inserted core could be easily replaced.Liquid nitrogen flow losses were measured under cases with two pipes geometries(outer diameter of 11 mm and 15 mm)and with mass flow rate in the range of 1~9 L/min.The experimental results validated the 3 D numerical model for helically corrugated pipes.Meanwhile,it is found that the pipe diameter has insignificant influence on the friction factors,which may provide theoretical basis for the design of the large pipes applied in practical applications by using the results of small pipes.