Papers by Keyword: Aero-Engine

Abstract: Thermal fatigue tests of superalloy GH536 were carried out at different maximum temperature. Three-dimensional numerical finite element computations were performed to simulate thermal fatigue test process. The crack initiation, propagation and thermal fatigue failure mechanism of GH536 plate at different maximum temperatures were obtained by experiments and numerical methods. Result shows that the crack initiation life is shortened and the crack growth rate is accelerated with the increase of the maximum temperature of thermal fatigue test. The numbers of appearing 1 mm length cracks are 180, 74 and 37, respectively, when the maximum temperature is 800°C, 850°C and 900°C respectively. So the thermal fatigue performance decreases with the increase of the maximum temperature. But in the thermal fatigue tests of different maximum temperature, the thermal fatigue crack initiation is all caused by a single crack initiation source, and the thermal fatigue cracks initiate transgranularly, develop and propagate intergranularly.

Abstract: As the premise, exploring aero-engine structure parts damage accurately can guarantee safety of the aero-engine structure parts, which are restricted by the working condition under the high temperature, high pressure and high speed. Analyzed the structure parts modal parameters by the modal theory, and researched the facts how to influence the modal parameters based on the different damage extent of the structure parts. Then construct the different damage extent structure models on the structure junctions with the finite element analysis method. At last, constructed and verified seven models with the example of aero-engine turbine structure damage in the constant temperature. The results were shown that the characteristic parameters with the inherent frequency and the inherent frequency deviation square can explore the structure damage accurately, but have no significant influence on the structural damages. So it will be important for us to ensure reliable operation and structure damage identification timely by the proposing the structure damage parameters.

Abstract: Large wear debris is an important indication of abnormal wear of aviation engines. Analysis of the relationship between particle parameters and the output signal plays an important role to improve the sensor sensitivity. A three-coil simulating sensor model is constructed using APDL finite element program. After analyzing the influence factors to the induced output voltage of the sensor, such as debris material, location, size, exciting current etc, the fitting characteristic curves are obtained, realizing the quantitative analysis. Simulation results show that the sensor model can effectively distinguish between conductive and non conductive, ferromagnetic and non ferromagnetic debris. The induced voltage can reach 10^-4 V for the 500 microns ferromagnetic abrasive particles. The characteristic curves provide important basis for further research on sensor structure optimization.

Abstract: The article presents some aspects of several years of work on the use of the vibroacoustic method (Non-Destructive Testing) for assessing a turboprop engine from a trainer aircraft. The functioning engine does not have an operating system for measuring vibration, and therefore the current levels of vibrations and its changes in trends are not known. In order to extend its service life, performing a number of works was required. On the basis of assessing the current state of the engine, opportunities for further exploitation were identified thus developing methodology for evaluating technical condition regarding the whole population. The paper shortly describes the object and equivalent tests on the engine. The article focuses on the methods prepared for extending life between overhauls required for turboprop engines and discusses the results received during their implementation.

Abstract: A diagnosis method of aero-engine faults based on Mamdani fuzzy inference is proposed in this paper. Regarding the fault symptoms of aero-engines as input of fuzzy inference, the proposed method establishes rules of inference from experts’ experience and distills the implication relationships. On this basis, the fault symptoms are combined with the implication relationships to obtain the probability of fault causes, so as to achieve the diagnosis of aero-engine faults. The results of experiments showed that the method is feasible and effective.

Abstract: Kinematics parameters calculation is the basis of piston pump design and performance analysis. Taking an axial piston pump with incline piston and spherical swash plate as the research object, Aimed at the deficiency of current formula for calculating piston pump kinematics parameters which included displacement, velocity and acceleration. In this paper, according to piston pump part motion geometry relationship, a correction kinematics algorithm is deduced by using the the spherical coordinate and cartesian coordinate transformation method, the analyse method and deduction procedure ensure the new calculating formula are precise in theory. Applying the calculating formula to an aero engine fuel axial piston pump, results show that. The displacement, velocity, acceleration according to the kinematics principle of piston pump, it can be used in the kind of piston pump kinematics parameters calculation and current calculating method evaluation.

Abstract: Active control of turbine blade tip clearance continues to be a concern in design and control of gas turbines. Ever increasing demands for improved efficiency and higher operating temperatures require more stringent tolerances on turbine tip clearance. In this paper, a turbine tip clearance control apparatus and a model of turbine tip clearance are proposed. The active clearance control (ACC) of aero-engine turbine tip clearance is evaluated in a lapse-rate take-off transient, along with the comparative and quantitative analysis. The results show that the resultant active tip clearance control system has favorable steady-state and dynamic performance and benefits of increased efficiency, reduced specific fuel consumption, and additional service life.

Abstract: With the rapid development of aviation technology, the performance of aero-engine continues to increase in China. However, Chinese Aero-engine lubricating oil real-time measurement technology is not mature, active airplane almost have no Aero-engine lubricating oil real-time measurement system, It requires further in-depth study.By research on Aero-engine lubricating oil measurement technology. First, it outlined the method and principles of measurement, and based on UG Open the analysis of Aero-engine lubricating oil system was developed. Through which an analysis of the model of Aero-engine lubricating oil, the spatial databases about sensor depth of immersion oil, aircraft attitude and fuel volume were built.,which can provide the data for the subsequent lubricating real-time oil measuring analysis .

Abstract: In view of the situation that the traditional fault tree is difficult to determine the probability of the basic events without considering the inherent uncertainly and imprecision of each basic event, the concept of fuzzy set is introduced which transforms various kinds of fuzzy numbers into triangular fuzzy ones to describe the probability of bottom events. Blurred the probability of the basic events in traditional fault tree, then the established fault tree is calculated and analyzed quantitatively, the fuzzy probability of top event of aero-engine can be gotten. The probability importance degree of each basic event under different sets is calculated and sorted for positioning the fault source precisely. Finally, the bottom events with higher probability will be obtained. The case analysis results show that the method gives a direct guiding significance for fault diagnosis of aero-engine, but also has a positive role for improving the reliability of the system.

Abstract: A large number of charged particles exist in the aero-engine gas path, the electrostatic monitoring technology mainly monitors the electrostatic charge in the exhaust gas of aero-engine by arranging an electrostatic sensor, and predicts the performance and working state of gas path components by using signal process algorithms and intelligent decision model. Considering the characteristics of the aero-engine gas path and the requirements of the gas path parameter detection, an electrostatic induction-based electrostatic sensor is built to detect the anomalously charged particles in the gas path on line, providing an important basis for aero-engine Prognostics and Health Management (PHM). Simulation experiments are implemented to investigate the time response and frequency characteristic of the output signals of the sensor and analyze the influence factors.