Papers by Author: Yong Lei

Abstract: Axial flow compressors work as an indispensable device in industry fields. Surge is a phenomenon of aerodynamic instability, which characterized by disruption of flow. When a compressor works in surge state, the vibration is so intense that it may causes accidents. Detecting surge timely and accurately not only insure safety of compressors but also is a key of active control of aerodynamic instability. Support vector data description (SVDD) is a one-class classification method developed based on the theory of support vector machine (SVM). In this paper, we introduce SVDD into the field of compressor surge detection. It demonstrates that SVDD method can give a warning far ahead of surge.

Abstract: In this paper, a fuzzy controller of hydraulic dynamometer water supply pressure was realized by Mamdani fuzzy inference system. The schema of database of fuzzy inference rules and member functions was introduced. An algorithm of fuzzy inference based on VC++6.0 was presented.

Abstract: The performance degeneration of components not only reduces the economy of aircraft engine, but also serious threat to the flight safety. Neural network with learning and reasoning abilities is widely used in fault diagnosis. In this paper, a neural network is established with improved BP method. 9 measured parameters of an aircraft engine are selected as features parameters. 21 kinds of gas path failure modes are coded with 5 bits. The data preprocessing methods and the effect of measurement noise are also discussed.

Abstract: It’s important to measure inlet total pressure field for aeroengine. Firstly, test scheme is discussed. Three pectinate total pressure probes, which can be rotated with an additional straight ring segment around the engine axis, are used to measure the total pressure field. The radial distribution of test points is designed via Tchebycheff integral method. Radial average and circumferential average are calculated according to the field data via area averaging method. At last the total pressure field is visualized via mapping the data to colors. Test results show that the total pressure distribution in main airflow is evener than that in boundary layers and the thickness of inner and outer ring boundary layer can be estimated.

Abstract: Engine running plays very important roles in a turbo-shaft engine production and maintenance. Traditional computer aided testing is just work as a data acquisition system to measure parameters and control some devices. In this paper, a CAT system is realized based on VXI and virtual instrument technology, which also communicate with the PLC, the ECU and the dynamometer, to provide a centralized information system for a turbo-shaft engine running. Multi-functions are realized to assistant users before, during and after experiments.

Abstract: Aero engine running is complex mechanical experiments. In the last two decades, many computer aided testing (CAT) systems were developed and employed in aero engine running. Traditionally, the main role of a CAT system is data acquisition, which developed with the client/server (C/S) architecture. Now, a CAT system plays more and more important roles in information management, such as measurement channels management, experiment design and management, data analysis and report management, and so on. Users may work on local place or on remote. So, it is not only a data acquisition system, but also an information system. In this paper, we introduce hybrid architecture of C/S and browser/server (B/S) to take advantages of both of them. For local users, clients are realized to provide local monitor and operation. For remote users, browsers provide not only real-time measurement data, but also querying and management of the history data. It demonstrates that the CAT system meets the requirement of aero engine running.