中文摘要：

为了合理设计系统的低温容器和安全装置（排气管、安全阀等）,需要了解失超后容器内氦工质的状态变化过程。首先对失超后超导磁体与氦工质间的传热过程进行了分析,进而研究了安全阀开启前后容器内的热力学变化过程和氦流在管道内的流动过程。基于质量守恒定律、能量守恒定律、熵方程和热力学状态方程建立了相应的数学模型,数值模拟了一浸泡磁体失超后容器内压力和排气管道内质量流量随时间的变化关系。计算结果表明：低温容器的最高工作压力约为5.8×101.325kPa;管道内的质量流量最大为0.645kg/s。综合考虑排气管的口径和容器的设计压力可以降低容器的最高工作压力。

英文摘要：

In order to design the helium vessel and safety system of the cryostat for superconducting magnet,it is necessary to know the state variety of helium after the quench of superconducting magnet.The heat transfer between the superconducting magnet and helium was analyzed,then the helium thermodynamic process of pre and post of opening the safety valve was studied.Also researched was the flow process of helium in the vent pipe.The mathematical model was obtained on basis of conservation of mass and energy,entropy equation and state equation.Finally,the pressure in vessel and helium mass flow in vent pipe after the quench of superconducting magnet were developed using this model.The results show that the highest working pressure in helium vessel is 5.8 × 101.325 kPa and the peak mass flow in vent pipe is 0.645 kg/s.The diameter of vent pipe and the design pressure of vessel should be comprehensively considered to reduce the highest working pressure.