【作者】 张杰；

【导师】 屈卫东；

【作者基本信息】 上海交通大学 ， 控制科学与工程， 2013， 硕士

【摘要】 航空发动机失稳主要是指其核心部件——压气机失稳。现阶段对于压气机失稳机理的研究表明，失稳是由压气机内部失速团的不断发展而形成的，它主要表现为两种形式：旋转失速与喘振。旋转失速与喘振既可同时发生也可单独发生，它们都属于压气机内部的气动不稳定现象，不仅会制约发动机运行效率的提升，严重时还将引起压气机叶片的剧烈振动，导致发动机机械结构损坏甚至空中停车。压气机不稳定信号检测是指通过对压力信号中所包含的失稳先兆进行分析处理，提取出压气机失稳的特征，并采用适当的预测算法和失稳判据对压气机失稳进行预警。压气机不稳定信号检测系统是防止压气机失稳的基础，也是发动机主动控制系统的重要组成部分。压气机动态模型是用来描述压气机压比、平均流量和流量扰动等的状态方程，是分析和判断旋转失速与喘振的基础，也是设计主动控制系统的理论基础。本文在原MG模型的基础上建立了非恒定转速下压气机不稳定信号的数学模型，给出了详细的推导过程，并对其进行了仿真验证。结果表明，该模型能较好地描述轴流式压气机的失稳现象（旋转失速与喘振），可以作为轴流式压气机系统稳定性分析、失速与喘振预测以及主动控制系统设计等研究工作的理论基础。压气机不稳定信号检测技术的关键是检测方法的研究。本文介绍了基于压气机出口压力信号的检测方法和基于第一级静压信号的检测方法。并详细地讨论了小波方差算法和相关积分算法。然后分别对这两种算法进行了基于压气机动态模型的仿真分析和基于压气机试车台架的实验数据分析。结果表明，两种算法都能对压气机不稳定信号进行有效地检测并给出失稳预警。但两种算法在普适性、准确性和时效性等方面又各有不同，且部分优缺点互补。最后，根据课题的技术要求，本文设计了压气机不稳定信号检测系统的方案，主要内容包括总体方案设计、检测算法设计、压力传感器选型以及系统架构设计。该方案将作为课题后期研究的基础，指导压气机不稳定信号检测系统的软硬件实现。更多还原

【Abstract】 The instability of aeroengine mainly refers to its key component, the compressor’s instability. So far, the study on the mechanism shows that the instabilities are caused by the development of stall cells which are generated from tip or middle of the blades. They mainly display in two forms, rotating stall and surge. Rotating stall and surge may occur simultaneously or individually. They all belongs to the pneumatic unstable phenomenon inside the compressor. They restrict the promotion of the efficiency for engine, especially cause violent vibration of the compressor blades, resulting in the damage of mechanical structure or even the air parking.The detecting of unstable signal in the compressor means first analyzing and processing the unstable inception mixed in the pressure signal, then extracting the instability characteristics, and taking proper prediction algorithm and instability criterion to give instability warning in the end. It is the foundation of preventing instability of the compressor, and it is also an important part of the active control system.Compressor model is used to describe the dynamics of pressure ratio, the average mass flow and the disturbances of mass flow. It is the basis for analyzing and judging stall and surge, and also for designing active control system. Based on the MG model, we established the mathematical model of unstable signal in the compressor under the condition of non-constant speed, giving the detailed derivation and the simulation results. The results show that the model can well describe the instability phenomenon (rotating stall and surge) in the axial compressor. It can be used for stability analysis of the axial compressor system, prediction of stall and surge and design of the active control system. The key to detecting technology of unstable signal in the compressor is the detecting method. In this paper we introduce the method based on the pressure signal at the outlet and the method based on pressure signal at the first stage, and also discuss the wavelet variance algorithm and the correlation integral algorithm. Then we analyze the two algorithms based on the dynamic model and the trial test data of compressor. The results show that both of the two algorithms can effectively detect the unstable signal and give instability warning. However, they are different in universality, accuracy and timeliness. They also have complementary advantages and disadvantages.Finally, according to the technical requirements of the project, we propose a scheme for the detecting system of unstable signal in the compressor. The main content includes:the overall scheme, the detecting algorithm, the selection of pressure sensors and the system architecture. The scheme will serve as the basis of the late-stage research, guiding the hardware and software realization of the detecting system of unstable signal in the compressor.更多还原