基于网格变形技术的流体机械叶轮动强度可靠性分析与多学科优化设计

Impeller is the key component of fluid machinery which influences the performance of machine and operation safety. The uncertainties in the manufacture and operation are needed to consider for the reliability design of key components such as impeller. The reliability design has been one of key techniques for improving the performance of product. In recent years, the high cycle fatigue (HCF) failure of impeller caused by fluid exciting load occurred many times which has been the hot point of research in the academic community and industry. The uncertainties such as the operation condition, impeller shape et.al are needed to be in-depth study. The proposal mainly concerns the turbomachinery such as industrial centrifugal compressor and pump. The research work is focused on some important and key problems including dynamic strength reliability of impeller and the method of multidisciplinary optimization for impeller. The main contents include: (1) The statistical law and modelling of morphology of impeller surface; (2) The mesh morphing method for the morphology change of impeller surface; (3) The statistical character of fluid exciting force on the impeller; (4) The statistical character and strength reliability of the response of impeller vibration. (5) The multidisciplinary reliability optimization of impeller. We will focus on the efficient algorithm for the qualification of uncertainty in the dynamical strength reliability of impeller. Another important problem is the modelling and solving methods for the multidisciplinary optimization which can consider the fluid performance and dynamical stress. The research result of this proposal will improve the theoretical basis for the high performance impeller design and strength analysis in the field of fluid machinery.

叶轮是流体机械的核心部件，影响机器的效率和运行安全。考虑加工、运行过程中的不确定性因素进行叶轮等关键部件可靠性设计和优化是提高产品性能的关键技术。近年来，流体激振力引起的叶轮高周疲劳失效问题日益突出，成为学术界和工业界关注的热点。需要考虑机组运行状态、叶轮结构等多种不确定性因素，对该问题进行深入研究。本课题以工业离心压缩机和泵等为研究对象，围绕叶轮动强度可靠性分析和多学科优化方法等共性基础问题开展研究工作，主要内容包括：（1）叶轮形貌不确定性因素的统计规律和建模；（2）叶轮表面形貌的网格变形表示方法；（3）叶轮流体激振力统计特性研究；（4）叶轮振动响应的统计特性和强度可靠性；（5）叶轮结构多学科可靠性优化。重点研究叶轮动强度可靠性中的不确定性定量化的高效算法，考虑叶轮效率和动应力等性能的多学科优化建模和求解方法。本课题研究成果可为流体机械高性能叶轮设计和强度分析提供理论基础。

叶轮作为流体机械的核心部件，其高性能和可靠性一直是研究的重点。本项目以叶轮结构表面形貌的不确定性的传播和定量化为主线，揭示叶轮流体激振力、叶轮振动特性、叶轮振动响应的统计规律并建立统计特性的高效分析方法。通过综合考虑流动性能、叶轮动强度性能，获得了具有高效率和高可靠性的叶轮设计方法。本项目的主要内容和重要成果包括：1）研究了叶轮表面形貌不确定性因素的统计规律并完成了能够表征叶片形貌变化的数值计算建模工作。2）研究了叶轮结构网格和通道流体网格的协同变形技术，该技术能够满足叶轮多学科优化中各学科模型一致性的要求。3） 完成了考虑形貌缺陷的气动性能鲁棒性优化。4）建立了轴流叶栅气弹稳定性拓扑优化框架，实现叶轮机械叶栅中弯扭耦合空心叶片空心区域的材料最优布置，使得叶栅在轻量化设计的同时可以保持气弹稳定状态。5）通过对宽弦空心风扇叶片结构进行参数化设计研究，完成了考虑型腔位置的叶片优化设计，得到了满足加工工艺条件的空心风扇叶片构型，成功实现了对开结构空心叶片的结构优化设计，提高了材料的使用性能和叶片结构设计效率。6）优化了离心叶轮动应力计算方法，搭建了离心叶轮动应力的计算框架，并以某实际事故离心压缩机半开式叶轮为计算对象，验证了方法的可行性与准确性。7）形成了高速旋转叶轮非定常信号的采集能力，基于沈鼓800试验台对半开式叶轮进行非定常脉动压力测试和动应力测试，为深入认识压缩机叶轮振动和破坏机理提供了有力支撑。8）针对旋转周期结构节径频率拓扑优化问题，利用波传原理有效实现了旋转周期结构的频率分析，提出了一套针对旋转周期结构节径频率拓扑优化框架。本课题研究成果为流体机械高性能叶轮设计和强度分析提供了理论基础，并具有较高的工程应用价值，已完成部分成果的转化。