基于QAR数据的LEAP-1A发动机起动活门故障分析及状态监控

LEAP-1A发动机自投入使用以来发生多起起动活门故障,对航班的运行造成极大的影响,会直接导致航班取消或延误。本文就LEAP-1A发动机起动活门的故障原因进行分析,建立基于QAR数据的起动活门状态监控模型,通过对起动空气压力关键参数的采集,提前捕捉到起动活门的失效状态。通过实例验证,该方法可以有效避免因起动活门失效导致的航班取消或延误现象。     

高超声速进气道辅助起动过程动态调控机理探索

研究了活门动态运动辅助进气道起动的过程。采用非定常模拟、动网格技术研究了旋转活门对二元高超声速进气道起动过程的影响,探索了在活门上开缝,利用活门前高速来流冲击的方法来抑制分离区的发展。结果表明,Ma∞=4时,活门辅助起动效果不理想,动态运动过程中进气道始终不起动;Ma_∞=5时,初始状态中,进气道内建立起超声速流场,活门贴壁的最终状态虽然内收缩段存在分离区,但是进气道成功起动。同时发现,活门后分离区是导致进气道不起动的主要因素。在铰接点处开缝时,可以有效抑制分离区,保证进气道起动。     

浅谈CFM56-7B发动机起动活门的监控方式

介绍了CFM56-7B起动系统的原理以及起动活门控制方式,对机队起动活门的故障进行归纳与分析,在无法获得制造厂家的技术支持下,反推出可指向起动活门的控制参数存储地址,探索出更加精准有效的监控方式与算法,为国内同行提供了一种可供借鉴的方法。     

MD-90飞机发动机起动系统故障初探

根据MD－90飞机发动机起动工作原理,着重介绍了可能引起起动系统故障的原因及排放方法,并用一实例说明其排放过程。MD－90飞机使用的动力装置是两台国际航空发动机公司（IAE）生产的V2500－DS双转子轴流式高涵道比涡扇发动机,它的起动系统是由向发动机提供一定压力气流的气源系统、起动机、附件齿轮箱及EEC等控制电路组成的,同时,7级、10级放气活门的开关正确位置对发动机的正常起动也起着至关重要的作用。V2500－DS发动机的可靠性高,但起动过程中却存在较多问题,以下就MD－90机队遇到的发动机起动过程中故障作一探讨。飞机…     

基于VC+SCM+FPGA的航空直流设备综合检测仪研制

飞机在电气控制系统中大量采用电磁阀、电动机构、控制活门等直流控制设备,分别用于操纵、燃油、环空等系统中.这些设备的工作电压、起动电压、门限电压以及各状态下的电压电流值等性能参数在其安全范围内能保证飞机安全飞行,但性能指标一旦超出全范围,如果不能被及时检测并更换直流设备,将会干扰和危害飞机的通信导航系统,降低设备的带负载能力,严重时会导致飞机失灵,从而酿成不可挽回的重大飞行事故.     

波音787飞机前起落架隔离活门故障分析

以一起波音787飞机前起落架隔离活门的故障为例,分析了787飞机前起落架隔离活门控制系统和部件的原理以及失效模式,并完善了机队解决方案。     

波音737NG飞机启动活门常见故障分析及处理

通过对飞机运行过程中启动活门出现的故障进行收集、分类和描述,剖析启动系统工作原理、启动活门组成及工作原理,判断故障发生的原因,提出排故的方法,为一线飞机维修人员高效完成启动活门排故工作提供参考.     

缝隙式机载真空压力调节活门的研制与设计

针对Cessna(塞斯纳)172R飞机真空系统故障率高的现象,研究了现有机载真空压力调节活门的结构特点,为该机型的真空系统设计一种缝隙式真空压力调节活门,该活门可视情况及时地清除缝隙部位污物,从而降低真空系统的故障率,提高飞机的安全性。     

论航材送修管理在提高波音737NG飞机引气系统可靠性中的作用

通过对波音737NG飞机引气系统的部件更换情况进行统计,分析出波音737NG飞机引气系统故障率最高的部件是预冷器控制活门和高压级调节器,且预冷器控制活门故障是导致引气系统空中故障的重要因素。因此,提出加强预冷器控制活门等部件送修质量管理、监控部件性能是提高飞机引气系统的可靠性的有效途径。     

燃油调节器起动供油特性研究

燃油调节器的起动供油特性的优劣,直接关系到发动机的点火能否成功。以弹用发动机燃油调节器起动供油装置为研究对象,建立起动供油系统的数学模型,并运用AMESim建立其仿真模型。重点分析了对起动供油特性起决定作用的关键部件——恒流量活门组件,得到了恒流量活门的初始开度、直径、节流孔直径、弹簧刚度、弹簧预紧力及喷嘴直径等设计参数变化对燃油调节器起动供油特性的影响趋势,为液压机械装置的设计、改进、改型和性能优化提供了理论依据。     

有翼高超声速再入飞行器气动设计难点问题

有翼高超声速再入飞行器是近年来的研究热点,气动设计是飞行器设计的关键。为了更清楚地认识有翼高超声速再入飞行器气动设计的难点问题,对有翼高超声速再入飞行器的发展、优势及总体任务剖面进行了介绍,从5个方面详细介绍了该类飞行器气动设计的难点问题,包括多约束复杂面对称气动布局设计、高温真实气体效应对气动特性影响、天地差异与天地换算方法、反作用控制系统(RCS)喷流干扰对气动特性的影响以及气动数据不确定度等,简要阐明了这些难点问题对总体设计的重要性以及初步的解决思路,为有翼高超声速再入飞行器气动设计提供了一些参考。     

Simulation and Analysis of Crashworthiness of Fuel Tank for Helicopters

Crashworthiness requirement of fuel tanks is one of the important requirements in helicopter designs. The relations among the protection frame, textile layer and rubber layer of the fuel tank are introduced. Two appropriate FE models are established, one is for an uncovered helicopter fuel tank without protection frame, and the other is for fuel tank with protection frame. The dynamic responses of the two types of fuel tanks impinging on the ground with velocities of 17.3 m/s are numerically simulated for the purpose of analyzing energy-absorbing capabilities of the textile layer and protection frame. The feasibility of the current crashworthiness design of the fuel tank is examined though comparing the dynamic response behaviors of the two fuel tanks.     

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation.      

突破技术趋同，波音再现竞争优势

 波音公司面临着来自空客公司的巨大挑战,企业战略性创新才是公司成功的关键。为此波音公司的全部战略性研究集中在扩大产品的差异性上,体现在3个方面：电子化（e-Enabled）运营环境、整体复合材料机身部件的制造技术和支持波音787客机的全球协同环境（GCE）。     

临近空间飞行器测控与信息传输系统频段选择

 临近空间飞行器是高性能信息化武器平台,测控（TT&;C）与信息传输系统是其信息保障的核心,而选择合理、可行的频段是展开系统设计的前提和基础。频段选择影响到整个技术方案的制定,是一个需综合考虑、影响深远并具有战略意义的关键问题,从国际电联（ITU）国际标准、高速数传、接收信噪比（SNR）、“三抗”、超视距中继、黑障、雨衰以及设备研制成熟度8个方面全面、细致论证了近空间平台测控系统的频段选择问题,最终得出在视距链路中以Ka频段为宜,在超视距链路中以Ku/Ka双频段为宜的结论。     

基于弯曲激波压缩系统的高超声速进气道反设计研究进展

总结了近十年来弯曲激波压缩研究的主要成果。提出了弯曲激波压缩系统的新概念,即利用特殊设计的楔形弯曲压缩面或空间弯曲压缩面,产生一系列与前缘弱激波相互交汇或叠加的压缩波系,从而使前缘激波弯曲,形成特殊的弯曲激波,它与波后的等熵压缩波来共同完成对气流的压缩。在此基础上,实现了由给定出口气动参数的超声速内流道反设计,实现了由给定压缩面压力分布和给定压缩面马赫数分布要求的型面反设计,实现了由给定激波波面的压缩型面反设计。研究证明,弯曲压缩面-弯曲激波压缩系统具有良好的综合气动性能,为高性能高超声速进气系统的气动设计提供了一种全新的设计方法。     

Experimental Study on Effects of Fuel Injection on Scramjet Combustor Performance

In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combus- tor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.     

(高)超声速流动试验技术及研究进展

近年来,与高速飞行器相关的(高)超声速流动受到了极大的关注。这类流动所具有的非定常性、强梯度和可压缩性对试验方法和风洞设计技术提出了挑战。超声速纳米示踪平面激光散射(NPLS)技术是由作者所在团队研发的非接触光学测试技术。它能够以较高的空间分辨率来揭示超声速三维流场的一个瞬态剖面的时间解析的流动结构。介绍了NPLS技术以及基于NPLS开发的密度场测量、雷诺应力测量和气动光学波前测量等方法,并回顾了这些技术在超声速边界层、超声速混合层、超声速压缩拐角、激波/边界层相互作用和光学头罩绕流等流动中的应用,清晰地再现了边界层、混合层、激波等典型流场结构及其时空演化特性。另外,为了模拟和研究高空大气条件下边界层自然转捩和超声速混合层的转捩特性,介绍了高超声速静风洞、超-超混合层风洞的设计技术以及层流化喷管的设计方法。     

Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis

Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved.