【作者】 卢杰；

【导师】 甘智华；

【作者基本信息】 浙江大学 ， 制冷及低温工程， 2006， 硕士

【摘要】 脉管制冷机由于冷端不存在运动部件，以其运行可靠、低振动、低磁噪声以及长寿命等显著优点受到人们的青睐。随着液氦温区脉管制冷机性能的不断改进，脉管制冷机将逐步取代传统的G-M制冷机，用来冷却红外传感器、超导磁体等。液氦温区脉管制冷机是冷却小型超导磁体系统较为理想的低温制冷机。本文回顾了小型制冷机直接冷却超导磁体系统的发展，结合脉管制冷机的性能特点，设计了用分离型二级脉管制冷机冷却的小型超导磁体低温系统。磁体线圈在工作电流35A的情况下，磁体中心区域产生5T的场强。用大型软件Fluent对液氦杜瓦的温度分布并用ANSYS对磁体磁场分布进行了数值模拟。具体研究工作如下： 1．脉管制冷机冷却小型超导磁体系统的总体设计 小型超导磁体采用再冷凝方式冷却，优点是磁体温度均匀，失超时通过蒸发液氦从而延长磁体温度上升到失超温度的时间。氦气通过缠绕在制冷机回热器上的螺旋形薄壁不锈钢管预冷后进入液氦杜瓦，杜瓦上法兰与制冷机二级冷头联接，下表面设计有导热翅片，用来冷却杜瓦内自然对流上升的饱和氦气。磁体失超等因素蒸发的氦气通过排出管送入室温储罐。磁体系统在工作电流35A，制冷机一级冷头40K的热负荷为5.12W，制冷机二级冷头4.2K的热负荷为100.1mW。 2．稳态运行过程数值模拟 为考察液氦杜瓦内的温度分布情况和磁场对系统各部分的影响，本文借助大型软件Fluent和ANSYS对系统中关键部件——液氦杜瓦的温度场和螺线管超导磁体的磁场分别进行了数值模拟与分析。模拟结果表明液氦杜瓦内温度分布均匀，产生的磁场对系统各部件的影响不大。 3．分离型脉管制冷机试实验 为了配合冷却超导磁体的需要，本文对研制的分离型二级脉管制冷机进行了试验研究。对于分离型二级脉管制冷机来说，第一级能否获得很好的制冷性能直更多还原

【Abstract】 Pulse tube cooler has several advantages, such as higher reliability, lower mechanical vibration, lower magnetic noise and longer lifetime, since it has no moving parts at the cold end. It will replace the convenienal G-M cooler to cool the infrared sensors and superconducting magnets with the performance improvement of the pulse tube cooler in the temperature region of liquid helium. And it’s also an ideal low-temperature cooler for cooling the small superconducting manget system.This paper reviews the development of the superconducting magnet system directly cooled by small low-temperature cooler, combined the performance of the pulse tube cooler, a small superconducting magnet system is designed cooled by a separated two-stage pulse tube cooler. The magnet coil can be charged with a current of 35A corresponding to a central field of 5T. The commercial software Fluent is used to simulate the temperature distribution of liquid helium dewar and ANSYS is used to simulate the distribution of magnetic field. The main research work is listed as follows:1. Design of a small scale superconducting magnet system cooled by pulse tube cooler.The small scale superconducting magnet is immerged into liquid helium and the liquid helium is used for cooling. The merit of this method is that the temperature of the magnet is uniform and the superconducting magnet can be cooled by the evaporation of the liquid helium when the magnet quenches. The incoming helium gas is pre-cooled which passes through a thin spiral stainless steel tube welded on regenerator using the first and second regenerators, and then flows into the liquid helium dewar. The top flange with fin of the dewar directly connected with the cold head of the two stage of the pulse tube cooler is used to condense the vapored saturated helium gas. The evaporated helium gas obtained by quench of the magnet is stored in ambient temperature container. The heat load of the cold head of the first stage (40K) and the second stage (4.2K) is 5.13W and 99.2W when the operating更多还原