【摘要】 自由活塞斯特林发电机(Free-Piston Stirling Generator,FPSG)以其密封性好、寿命长、振动小的特点，在空间核电等小型紧凑能量转换系统中具有重要应用前景。针对FPSG的数值模拟分析难点，本文基于热-动-电多物理场相互作用机理，构建了描述FPSG整机运行特性的三阶动态全耦合模型。在模型中，构建了基于准一维非定常流动假设气体热力循环控制方程，结合了基于刚体力学分析的机械动力学方程，并耦合了基于非线性电磁参数的电磁动态方程，采用高阶数值积分算法实现了热力、机械与电磁子系统的统一耦合求解，开发了适用于FPSG的三阶动态特性分析程序。基于100 W级FPSG参考数据开展了模型验证，获得的P-V(压力-体积)指示图及输出功率计算结果与文献参考值符合较好，相对偏差约7.5%，表明本文建立的三阶耦合模型及分析程序能有效预测FPSG的动态响应与能量转换特性。在此基础上，进一步分析了100 W级FPSG的活塞运动特性、工质循环流动特性，以及发电机电输出特性。本研究对FPSG的系统设计、性能预测及优化分析具有参考意义。更多还原

【Abstract】 [Background] The Free-Piston Stirling Generator(FPSG) is regarded as a key enabling technology for deep space exploration, owing to its high efficiency, extended lifespan, and superior reliability. However, owing to the absence of rigid mechanical constraints, the FPSG operates as a self-excited oscillation system governed by intricate non-linear interactions among gas dynamics, mechanical inertia, and electromagnetic forces. Consequently, numerical simulation of its performance is complicated, where a trade-off between computational efficiency and the precision required to resolve transient coupling effects is rarely achieved by existing methods. [Purpose] This study aims to develop a high-fidelity analytical framework for FPSGs to resolve existing deficiencies in transient performance prediction and clarify the thermal-dynamic-electric coupling mechanism. [Methods] Firstly, governing equations based on quasi-one-dimensional unsteady flow assumptions were utilized to resolve mass, momentum, and energy conservation within the thermodynamic cycle. Then, mechanical dynamics were derived via rigid body kinetics, while the electromagnetic subsystem was modeled incorporating non-linear parameters. Subsequently, solution of this stiff, high-dimensional system was executed using a high-order Runge-Kutta-Fehlberg(RK45) numerical integration algorithm. Finally, model validity was substantiated through comparison with a 100 W-class prototype to obtain P-V(Pressure-Volume) indicator diagram and output power. [Results] Simulation and verification results indicate the agreement between the calculated P-V indicator diagrams and reference data was indicated by the simulation results. Specifically, an indicated power of 142.42 W is reported against a reference of 132.48 W, representing a relative deviation of approximately 7.5%. With the system frequency maintained at 29.4 Hz, a phase angle of 77.3° is observed between the displacer and power piston. Additionally, complex cyclic behaviors, including working fluid compressibility, transient pressure wave propagation, and non-linear electromagnetic damping, are effectively captured. [Conclusions] The complex transient response and energy conversion characteristics of the FPSG are effectively predicted by the developed third-order dynamic model proposed in this study. Through the rigorous resolution of multi-physics coupling, a robust theoretical framework is provided for the design, performance prediction, and optimization of nuclear power conversion systems intended for deep space exploration.更多还原