间隙流动对屏蔽电机主泵转子系统稳定性影响的研究

The canned motor RCP is the key facility of the third generation nuclear reactor. However, the rotordynamic stability of the RCP is still an unsolved issue, and becomes a technique problem for the development of nuclear power. The annular flow (AF) between the shielding cans of rotor and stator in the RCP is of unique geometric ratio and specific operation conditions. Difficulties have been encountered when the classic theoretical methodology, which is developed aiming at similar AFs, is adopted. Thus, new model has to be built in order to accurately describe the rotordynamic characteristics of the AF in the RCP. Those rotordynamic characteristics of the AF are affected by multiple factors. The relationship between the affecting factors and the rotordynamic characteristics is not clear yet. Meanwhile, both the rotordynamic characteristics and the temperature distribution of the motor are affected by the thermal effect of the AF. The AF will be studied by a combination of theoretical analysis, numerical simulations and a series experiments. The flow mechanism of the AF will be explored. The relations between the affecting factors and the rotordynamic characteristics of the AF will be inquired. Research will be done on the thermal conduction properties of the AF. Theoretical model and analysis method will be established to accurately predict the rotordynamic characteristics of the AF. The interaction mechanism between the AF and the rotor system and the dynamic properties of the coupled system will be revealed. The principles of the AF affecting the stability of the rotor system will be studied. The results of this research will be served as the fundamental scientific basis of both the system stability design and safe operation of the canned motor RCPs.

屏蔽电机主泵是第三代核反应堆中的关键设备，其转子稳定性至今仍存在问题，已成为核电发展的技术瓶颈。位于主泵转子与定子屏蔽套间的间隙流动具有特殊的几何比例和运行条件，用于分析此类间隙流动的传统理论模型在运用到屏蔽电机主泵时遇到了困难，需要建立新的模型以更准确描述间隙流动的动力特性。间隙流动受入口预旋等多因素影响，各因素综合作用规律尚不明确。同时，间隙流动的传热特性直接影响其动力特性和整机的温度分布情况。本课题拟通过理论分析、数值模拟和实验研究相结合的方法，探索间隙流动的流动规律，研究多种因素对间隙流动的动力特性的影响，研究间隙流动传热特性，建立准确描述间隙流动动力特性的理论模型和分析方法，揭示间隙流动与转子系统的相互作用机理与耦合动力学特性，掌握间隙流动对转子系统稳定性的影响规律，为屏蔽电机主泵转子系统稳定性设计和安全运行提供科学依据。

屏蔽电机主泵是核动力装置一回路的核心设备，是反应堆的心脏，其安全稳定运行是反应堆安全的保障。准确的转子动力学分析结果和快速准确的优化设计方法对屏蔽电机主泵转子系统设计至关重要。为了使屏蔽电机主泵的转子动力学特性和安全性能得到准确的分析和预测，有必要对屏蔽电机内部的间隙流动以及间隙的设计方法进行系统性的研究。. 本研究主要包括间隙流动流动特征研究，多因素影响下间隙流动动力特性研究，间隙流动传热特性研究，及屏蔽电机主泵间隙流动-转子耦合动力特性研究四个部分。研究发现屏蔽电机主泵转定子间隙流动会给系统带来较大的负刚度（约为轴承的10%）和附加质量，该间隙流动的存在增大了轴承负载并降低了转子系统的临界转速（下降约18%）。. 通过基础研究，项目组提出了屏蔽电机主泵转定子间隙以及飞轮间隙的设计方法，填补了国内在该领域的空白，能为后续大型屏蔽电机主泵的转子系统设计及海洋核动力平台所需的屏蔽电机主泵的设计提供坚实的技术支撑。