北京正负电子对撞机重大改造工程中超导四极磁体传热与流动计算

Heat Transfer and Thermal Fluid Calculation of Superconducting Quadrupole Magnet in BEPCⅡ

超导四极(SCQ)磁体是北京正负电子对撞机重大改造工程(BEPCⅡ)的关键设备之一。本文对SCQ磁体恒温器进行稳定运行状态下传热和流动计算。计算得到了磁体在低温下的热负荷以及磁体恒温器内各组成部分的温度分布,并在此基础上,提出减小SCQ磁体热负荷的方法。比较计算了SCQ磁体采用超临界和过冷液氦两种冷却方式对磁体稳定运行的影响。

A pair of interaction region superconducting quadrupole （SCQ） magnets in Beijing Electron-Positron Collider Upgrade （BEPC Ⅱ ） are key facilities cooled by liquid helium in the constrained cooling channels. The heat loads to the SCQ magnet and temperature contour of the magnet cryostat are calculated. Based on the calculation, the method to decrease the heat load is presented. The results of thermal fluid modeling for the magnet cryostat are also provided. Two types of cooling schemes, the subcooled liquid helium and the supercritical helium flow, are numerically analyzed.