基于多物理场耦合分析与逆问题优化设计的灯泡贯式流机组极靴表面烧蚀故障研究

The reveal of generator over heat failure mechanism and the study of inverse problem optimization design based on the multi-physics field analysis provide important academic and engineering realistic significance in the field of comprehensive simulation analysis in multi-physics field with multi-platforms and targets and the field of accurate optimization design.In order to achieve the fault occurrence mechanism of the overheat ablation of pole shoe surface of tubular hydro-generator,and enhance the design standard,the following research will be done in this project.Based on the multi-physics field coupled theory,the interation relations between the conductivity,permeablity,heat transfer and flow performance of material during the loss and heat generation of pole shoe are considered,and the coupling mechanism between the electromagnetic field and fluid field and temperature field are researched,then the 3D electromagnetic-fluid-temperature field coupling model for the pole shoe loss and heat calculation is built and validate.Moreover,in order to optimize the no-load voltage waveform quality and pole shoe loss and heat,the electromagnetic-temperature field inverse problem optimization model is built.At last,the change rules of pole shoe loss and heat and no-load voltage waveform quality with the generator structure paremeters are got,the fault occurrenc machansim are revealed,the protection design principles are presented,the practical optimization design strategy are obtained.The research is helpful enhancing the assess level and design standard of loss and heat of tubular hydro-generator,and avoid the overheat ablation failure.

基于多物理场耦合分析的发电机过热故障机理揭示与逆问题优化设计研究，在电机多物理场、多平台、多目标综合仿真分析与精确优化设计领域，具有重要理论学术价值与工程现实意义。本项目针对灯泡贯流式机组极靴表面过热烧蚀新型故障发生机理揭示与防范优化设计，拟采用多物理场耦合分析理论，深入研究极靴损耗发热产生过程中，电磁场、流速场与温度场耦合机理以及材料导电、导磁、传热、流动性能的相互作用关系，研究、建立并验证极靴损耗发热的三维电磁场-流速场-温度场耦合分析模型；同时考虑极靴损耗发热与机组空载电压波形质量两方面优化要求，提出电磁场温度场综合逆问题优化设计模型；获得机组结构参数对极靴各部分损耗发热与机组空载电压波形质量的影响规律，揭示此类故障发生机理，提出针对性防范设计原则，形成较为完善可行的优化设计策略。其成果将为提升发电机损耗发热设计评估水平、避免各类过热烧蚀故障，提供理论支撑与设计参考。

随着中高水头水电资源逐渐开发完毕，低水头水电资源的开发越来越受到国内外重视。与开发中高水头水电资源的冲击式、混流式、轴流式水轮发电机相比，灯泡贯流式水轮发电机是一种开发利用低水头大流量水电资源的优良机型，可节省土建费20-30%、增加发电量3-5%，因此在我国得到了长足发展与广泛应用。然而，近年来，国内外多个发电机制造厂商设计生产的大型灯泡贯流式水轮发电机，屡次发生磁极极靴铁芯过热烧蚀故障，给发电机制造企业、发供电企业以及用户，带来了严重的经济损失。因此很有必要予以分析和治理。. 本项目针对灯泡贯流式机组极靴表面过热烧蚀新型故障的发生机理揭示与防范优化设计问题，基于电磁学、传热学、数值分析理论，综合考虑上述故障形成中的电磁、发热、通风、散热等多种物理现象的综合作用，建立并验证了极靴构件损耗发热的三维机-电-磁-热多物理场强耦合模型分析模型，并基于区域分解思维，初步设计并运行成功相关并行求解算法。在此基础上，通过相关现场分析与多物理场计算，获得了机组部分结构参数对极靴构件自身损耗发热与机组空载电压波形质量的影响规律，进而揭示了此类故障产生机理。在此基础上，兼顾发热抑制与空载电压波形质量两方面的设计要求，初步提出了此类故障的治理改造设计思路，并在ZL电站34MW故障机组的维修改造中，得到了实际应用，收到令人满意的治理成效。相关成果能够为提升发电机损耗发热设计评估水平、避免此类极靴铁芯表面过热烧蚀故障，提供较好的理论支撑与设计参考。