基于热磁耦合分析的高性能磁屏蔽系统设计

近零磁工作环境是实现无自旋交换弛豫(SERF)原子自旋惯性测量装置的必要条件,但在实际中由于装置内部气室加热和环境温度变化引起的磁屏蔽性能变化是影响系统性能的一个主要因素。基于热-磁耦合理论建立了惯性测量装置的有限元分析模型,对加热条件下磁屏蔽筒内磁场均匀性及其剩余磁场进行了分析。结果表明,气室加热至200℃时,附近温度场对磁屏蔽筒内部磁场梯度的影响较小可以忽略,但磁屏蔽筒内部剩磁相比数值解增加了0.09nT。同时基于上述模型对磁屏蔽材料的温度稳定性进行了研究,当采用高温稳定磁屏蔽材料时,惯性测量装置的长期稳定性有所提高,但磁屏蔽效能会降低。该研究为高性能磁屏蔽筒的热磁耦合误差及磁屏蔽材料性能的研究提供了理论与方法支撑,同时也为SERF原子自旋惯性测量装置的研制提供了有力的技术保障。

Design of High Performance Magnetic Shielding System Based on Coupled Thermomagnetic Fields Analysis

High performance spin-exchange-relaxation-free(SERF)inertial measurement units require nearly zero magnetic fields.However,the change of the magnetic shielding performance caused by the heating of the gyroscope cells and the change of ambient temperature is one of the main factors affecting the system performance.Finite element analysis model of the inertial measurement unit is established based on the coupled thermomagnetic fields theory.The magnetic field uniformity and residual magnetic field in the magnetic shielding cylinder under heating condition are analyzed.When air chamber is heated to 200℃,the temperature field nearby has little effect on the magnetic field gradient inside the magnetic shield bucket and can be ignored.Compared to numerical solution,the remanent magnetism increases by 0.09nT.On the basis of this research,the temperature stability of the magnetic shielding material is researched.When the high temperature stable magnetic shielding material is used,the long-term stability of the device is improved,but the magnetic shielding effectiveness is reduced.This paper provides theoretical and method support for the research on thermomagnetic coupling error of high-performance magnetic shielding system and magnetic shielding material performance,which offers technical guarantee for the development of SERF inertial measurement units.