并联磁路混合励磁旋转涡流制动器的多物理场耦合研究

The braking performance of the eddy current brake is reduced even results in damage of the eddy current brake due to the increase of the temperature of device in the long-term working condition. Regarding the issue above, using the theoretical analysis of electromagnetic field and temperature field as an entry point, the mechanism of cross-coupling and evolutionary effect will be researched mainly. Based on the background of high-speed train braking system, a novel hybrid excitation eddy current brake with parallel magnetic circuit is proposed. First, based on the equivalent magnetic circuit model and the layered model, the exact analytic model of the hybrid excitation eddy current brake will be built. Secondly, a complete thermal network model will be built on the basis of calculating the convective heat transfer coefficients of the eddy current brake according to the dynamic mesh model and dimensionless equations. Then, a multi-physical fields coupled model of eddy current brake will be established to analyze the coupling influence and its mechanism between electromagnetic field, temperature field and fluid field. Based on these results, the design method will be studied considering the temperature rise balance between the primary and secondary. Finally, the prototype and experimental platform will be processed. The braking torque and temperature rise characteristics will be tested to verify the veracity of the theoretical analysis results and the proposed model. The multi-physical fields analysis method and design method of eddy current brake presented in this paper can lay an important theoretical foundation for its practical application, Therefore, this subject will produce important theoretical research value.

本项目针对涡流制动器在长期工作条件下，由于装置温度升高而导致其制动性能降低、甚至装置损坏的问题，以涡流制动器的电磁场、温度场理论分析为切入点，主要研究其多物理场交叉耦合与演化作用机理。本项目以高速列车制动系统为应用背景，提出一种新型并联磁路混合励磁涡流制动器。首先，结合等效磁路模型和分层模型，推导其精确解析模型；其次，在根据动网格流体场模型及对流换热实验关联式计算对流传热系数的基础上，搭建完整的热网络模型；然后，建立涡流制动器的多物理场耦合模型，分析其电磁场、温度场和流体场之间耦合影响及其作用机理，并在此基础上，研究兼顾初、次级部分温升的设计方法。最后，加工制造样机，搭建实验平台进行制动、温升特性相关实验，验证前期建立模型及理论分析结果。本项目研究的涡流制动器的多物理场耦合分析及设计方法，可为其在相关领域的实际应用奠定理论基础和依据，具有重要的理论研究价值。

随着时代的发展，在设计涡流制动器等电磁设备时，不仅限于其电磁性能，而是需要全面地分析其电磁场、流体场、温度场、应力场等物理场，真实地预测出其实际运行工况。然而，受限于现代计算机的计算速度，通过有限元法计算涡流制动器的多物理场耦合作用是非常耗时的，而推广到优化设计过程更是不现实。因此，最有效的方法的尽可能地提高解析模型的精度，建立多物理场解析模型，并推广到实际优化设计过程中。围绕上述问题，本项目做了如下工作：.1. 提出了一种开槽次级导体轴向ECB的改进解析模型。经过有限元法和实验验证，改进后的解析模型与传统解析模型相比，计算精度显着提高，并且其计算时间显著低于3D有限元法。.2. 对开槽次级导体轴向ECB的流体流动和热分析进行了分析。使用CFD计算和最小二乘法获得对流传热系数的解析计算式。经过仿真和实验验证得知，通过该解析计算式可以计算不同设计参数下ECB的对流传热系数，而不是每次都用CFD计算。并且相比于传统实验关联式，计算精度得到提高，保证了整体计算精度在优化设计阶段可接受范围内。.3. 针对双边轴向永磁式涡流制动器，研究了电磁场、流体场和温度场特性、三个物理场之间的关系以及相互影响机理。.本项目中推导出的电磁解析模型、对流传热系数计算式以及多物理场分析理论可以用于涡流制动器的优化设计阶段，并且给相关设计人员提供理论指导。

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