某型航空发动机常见振动故障分析

针对某型发动机结构特点以及装配过程中与振动相关的要素,分析该型发动机生产过程中常见振动故障情况,包括转子不平衡、转子不平衡与转静件碰摩并发故障、转子不对中、高低压涡轮转/静件碰摩以及设备原因,总结了该型发动机常见振动故障诊断及排除方法.     

Effect of alloying elements on the behaviour of TiAl-based alloys

TiAl-based alloys containing Nb, Mo and Cr have been produced by induction melting both under an Ar atmosphere and in vacuum. Fracture toughness and isothermal oxidation tests at 900 °C have been performed on a number of alloys in order to evaluate the effect of alloying elements on both fracture toughness and hot corrosion. The results highlighted that there is an alloy composition range that could allow to obtain a good compromise between high temperature oxidation resistance and fracture toughness. In fact only for a selected Al/Ti ratio and a limited content of alloying elements it is possible to attain the alloy microstructural control and, for Mo free alloys, good protectiveness against oxidation.     

一种航空发动机SVM模型辨识方法与仿真

航空发动机是一个十分复杂的气动热力过程系统,具有很强的非线性,为了对航空发动机进行有效的控制及故障诊断,研究其工作特性,必须建立其数学模型。依据某型航空发动机试验数据,采用基于将试验数据代入对象方程的算法进行系统辨识,建立了该型发动机某一稳态点的状态变量数学模型(State Variable Model)。验模表明,所建模型精度较高,鲁棒性好,能够实时准确反映发动机性能,满足后续控制系统的研究和设计。     

航空发动机液压负载系统设计及应用

为了提取某型航空发动机带动液压泵的机械功率,通过分析航空发动机液压负载系统现状,结合被试对象和试飞平台设计研制了某型航空发动机液压负载系统,详细阐述了该系统的工作原理,并进行了换热计算、管路压力损失计算、集成安装设计等。经地面调试和飞行试验验证,结果表明:系统集成度高、换热效果好、维护性好,能够满足该型航空发动机液压泵机械功率的提取要求。     

航空发动机积炭清洗剂初探

本文简介了积炭的形成过程及其危害，国内外现有去炭工艺水平，重点分析了有机积炭清洗剂各成份的作用和影响，确定了工艺配方，并对其性能和使用情况作了测试。     

航空发动机的几种备份控制系统

备份控制系统是航空发动机不可缺少的一个部分,它是发动机的可靠性的重要保证。这里介绍了航空发动机控制系统设计中的几种备份控制系统,并以实例说明其结构组成、工作原理、具体实现以及各自的优缺点,为航空发动机数字控制系统以及地面动力控制系统的设计工作提供参考。     

Isothermal oxidation behavior of FeCo–2V intermetallic alloy

Isothermal oxidation behavior and the nature of oxide layer formed during oxidation of FeCo–2V alloy were characterized in the temperature range of 500–600 °C. Oxidation kinetics of the alloy follows a parabolic rate law. SEM and XRD studies indicate the formation of an iron rich outer oxide layer and an inner solute rich layer containing cobalt and vanadium rich oxides. The oxidation mechanism of the FeCo–2V alloy is similar to that of low alloy steels. During the initial stages, preferential oxidation of iron and cobalt occurs at the alloy surface and leads to the formation of a solute rich inner layer. Continued oxidation occurs through oxidation of iron and cobalt at the outer layer and internal oxidation of inner layer. The iron rich oxide layer formed at the surface on oxidation of FeCo alloy is semi-conducting in nature and may not provide the necessary insulating barrier required at the surface to minimize eddy current losses during A.C. applications.     

Laser beam weld-metal microstructure in a yttrium modified directionally solidified Ni3Al-base alloy

The microstructure of laser beam weld-metal of an yttrium doped directionally solidified alloy IC 6A, with chemical composition Ni–16Al–8.5Mo–0.12B–0.05C–0.03Y (at.%) was studied. The dendritic microsegregation observed within the fusion zone indicated that dendrite cores were slightly depleted in molybdenum and aluminum and the interdendritic regions were also considerably enriched in yttrium. Severe cracking in the weld-metal was observed and was found to be closely associated with interdendritic eutectic-type microconstituents identified as consisting of γ, γ′ and Ni–Mo phases. An yttrium-rich phase (Ni₃Y) was observed in some interdendritic regions containing the eutectic γ, γ′ and Ni–Mo products. Their formation was discussed in relation to plausible microsegregation induced alteration of primary solidification path during cooling from welding temperatures.     

航空发动机火焰筒X射线检测时黑线缺陷的研究

本文通过对ＧＨ１６３合金ＴＩＧ焊焊缝金属偏析规律的试验研究，探讨了航空发动机火焰筒Ｘ射线检测时Ｘ光胶片上黑线缺陷的形成机制，并提出了有效的防治措施。     

某发动机一级涡轮叶片断裂分析

以某发动机涡轮一级事故叶片为研究对象，对断裂叶片进行了宏、微观形貌观察，硬度测试以及断口成分检查，分析了叶片裂纹的产生与发展过程，探讨了叶片断裂失效的原因。结果表明，叶片断裂模式为机械疲劳断裂。提出了预防措施。