民用飞机航材预测与配置管理技术综述

航材作为综合后勤保障(ILS)的物资基础,其科学的预测与合理的配置是有效保障民用飞机安全经济 运行的前提。为了使利益攸关方(制造商、运营商、维修商等)实现共赢,本文针对现有民用飞机航材预测与配 置管理技术进行研究,并探讨其发展趋势。首先,介绍了民用飞机航材预测技术的研究现状;然后,论述了民用 飞机航材配置管理技术的研究现状;最后,在总结现有关于航材预测与配置理论和方法的优势与不足的基础 上,对民用飞机航材预测与配置管理技术的发展进行了趋势分析,为国产民用飞机航材综合管理提供参考,进 而提升民用飞机维修保障体系的完善程度。     

民用飞机航材销售费用分解结构模型研究

当前我国民用飞机缺乏合理、灵活的航材价格计算模型,而合适的航材销售费用分解结构模型可以降低运营成本、增加利润。本文综合多种因素的影响,从不同的维度对航材定价进行研究,阐述民用飞机航材成本费用的构成;从全寿命周期的角度对航材价格影响因素进行分析,构建国产民用飞机全寿命周期不同航材在多种因素影响下的销售费用分解结构模型。结果表明：构建的分解结构模型合理、有效,能够指导国产民用飞机型号航材定价分析,航材销售价格影响因素分析能够结合不同部门维度或工作维度对全寿命周期内的航材成本进行结构分解,实现利润最大化。     

民用飞机IRS冗余配置下融合算法研究

为了确保民用飞行的安全,大型民用飞机一般配备冗余的导航系统,如A320一般装有三套IRS。如何利用冗余的传感器信息提供最重的位置信息,成为民用飞机飞行管理系统亟待解决的关键技术。本文对冗余配置下如何进行三套IRS的融合进行了研究,提出了基于历史信息获取最佳混合位置的方法,并通过仿真分析验证了算法的有效性,为FMS导航功能关键技术的实现提供了理论基础和技术支持。     

民用飞机航材支援网络选址因素权衡方法研究

民用飞机航材支援网络作为主制造商为客户提供航材的必要媒介,合理地搭建该航材支援网络有利于提高主制造商的服务品质和客户运营能力。基于Kriging 方法,提出一种定性与定量相结合的民用飞机航材支援网络选址因素权衡方法,对选址因素进行梳理和分类,获取选址定量分析数据需求,并运用所提方法进行民用飞机航材支援网络选址因素权衡,...     

基于GRA-IPSO-SVM的航材携行需求预测研究

异地执行飞行任务中航材需求的准确预测是做好携行保障的主要内容之一,为此提出灰色关联度（GRA）与改进的粒子群算法（IPSO）及支持向量机（SVM）相结合的航材预测方法。首先运用GRA 对航材携行需求的影响因素进行分析;其次引入活性因子和非线性惯性系数改进粒子群算法,并通过IPSO 对SVM 参数进行寻优;最后使用优化后的SVM 模型预测航材需求。结果表明：GRA-IPSO-SVM 方法预测结果的均方根误差比PSO-SVM 方法下降0.16,平均绝对百分比误差下降2.18%,且预测时间减少了0.7 s。     

军用航材智能化保障的技术构建

针对军队航材保障效率较低、反应时间过长等问题,结合国防与军队信息化、智能化建设的实际,提出了军用航材智能化保障模式;通过运用物联网、神经网络、云计算等方法,对智能化保障模式各功能的实现提出支撑技术,航材智能化保障模式各项功能得以实现;通过对军用航材智能化保障进行模式构建,并就该模式下各功能模块的实现提出支撑技术,革新保障方式,有效提高了航材保障的效率。     

一种基于任务的航材备件预测方法

航材备件是影响军机完好率的主要因素之一,为控制成本有必要对备件进行最优配置。因此,提出了一种基于任务的军机航材备件预测方法,首先按照军机能力目录对机载成品进行分类,其次将能力按照军事任务所需进行分组,接着统计特定时间段内的历史故障数据得到机载成品的故障率与维修速率,最后建立排队论生灭过程模型,实现特定任务下的航材备件需求预测。理论分析和验证结果表明,该方法能实现较为精确的航材备件需求预测,在保证飞机完好率的同时控制航材备件成本。     

基于Matlab与VB混合编程的压痕直径测量软件设计

通过压痕直径测量工程应用实例,介绍了基于COM组件技术的Matlab与VB混合编程的可视化程序设计方法和及实现步骤。基于COM组件技术的混合编程方法能够大大提高程序开发的效率,降低编写难度,增强程序的可维护性,在诸多方面具有单一编程语言所不具有的优势。     

基于B/S的民用飞机结构修理方案平台的设计与实现

民用飞机结构修理过程中有时会遇到超出手册范围的情况,在制定超手册结构修理方案的过程中,为了给维修工程人员提供相关的参考方案,本文开发一种基于Browser/Service（B/S）的民用飞机结构修理方案平台。首先从业务流程和平台功能角度对平台需求进行分析;然后基于平台开发所使用的各项技术,从平台架构、数据库、平台功能模块三方面对平台设计进行详细分析;最后通过实际操作演示,对平台的主要功能模块进行测试。结果表明：该平台人机界面友好、扩展性良好、操作简单方便,实现了民用飞机结构飞机损伤信息和修理方案电子化,能够根据损伤信息自动推荐出数据库中存储的若干修理方案,为维修工程部门更快制定超手册修理方案提供支持。     

五轴数控机床后置处理算法研究

五轴数控加工技术基于五轴数控编程理论,对五轴机床的结构形式和运动特性进行分析,通过后置算法求解,得到后置处理坐标转换公式,并将前置处理产生的刀位数据文件(CLFS)转换成机床执行的CNC程序,再利用Visual Basic语言编程创建坐标转换界面,实现数控程序自动转换。     

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.      

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.     

Preparation of Highly Dispersed Antimony-doped Tin Oxide Nano-powder via Ion-exchange Hydrolysis of SnCl4 and SbCl3 and Azeotropic Drying

Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.     

Effects of Mo on the Microstructure and Hydrogen Sorption Properties of Ti-Mo Getters

The effects of Mo on the microstructure evolution, porosity and hydrogen sorption properties of Ti-Mo getters are investigated in this work. The results show that the addition of Mo prolongs the densification process of Ti-Mo getters and results in a significant amount of sintered pores. With the Mo content increasing, the porosity of getters firstly increases reaching the maximum value as it at- tains about 7.5wt.%, and then drops. At the room temperature, the hydrogen sorption property of getters increases progressively with the Mo content increasing, but the tendency is not very clear before its content lies below 2.5wt.%. When the Mo content achieves about 7.5wt.%, the hydrogen sorption property proves to be the best. The discussion is made about the above mentioned phenomena inclusive of hydrogen sorption properties of getters under different activation conditions (from 500-750 ℃).     

超声速燃烧数值模拟中的湍流与化学反应相互作用模型

高精度数值模拟有助于理解超声速湍流燃烧中湍流与化学反应的相互作用,可为发动机燃烧室等工程应用设计提供可靠的预测模型。除直接数值模拟外,目前在湍流燃烧应用中使用的大涡模拟和雷诺平均Navier-Stokes模拟均需要借助模型模化发生在湍流小尺度上的流动与化学反应过程对湍流大尺度运动的影响。现有的湍流与化学反应相互作用模型大致可分为:火焰面类模型和概率密度函数类模型,2类模型在不同的应用中各自具有优势和局限性。此外,现有模型大都基于低马赫数燃烧,而超声速燃烧中通常会伴随快速混合、局部熄火和再着火以及激波等复杂过程,这为发展其中的湍流与化学反应相互作用模型提出了更多的挑战。     

适于低轨卫星IP网络的单核共享树组播算法(英文)

为了解决低轨卫星IP网络中现有典型源组播算法的信道资源浪费问题,本文提出了一套单核共享树组播算法,即核心群合并共享树(CCST)和加权核心群合并共享树(w-CCST)算法。CCST 算法包括动态近似中心(DAC)选核方法和核心群合并组播路径构建方法。DAC方法专为周期、规律运动的低轨卫星网络提出,不需要复杂的星上计算。在核心群合并方法中,以核节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,从而使得组播树的树代价最小,大大提高了网络的带宽利用率和组播传输效率。w-CCST 算法中所提出的加权因子可以调整树代价和端到端传播时延之间的折衷程度,因此,可以通过调整加权因子来适度增大树代价、降低端到端传播时延以支持某些端到端时延要求苛刻的实时组播业务。最后,与低轨卫星 IP 网络中典型算法进行了性能比较,仿真结果说明,CCST 算法的平均树代价比其它算法显著降低,w-CCST 算法的平均端到端传播时延小于 CCST 算法。     

Jet Vectoring Control Using a Novel Synthetic Jet Actuator

A primary air jet vectoring control system with a novel synthetic jet actuator (SJA) is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either “push” or “pull”, one novel synthetic jet actuator can fulfill both “push” and “pull” functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various appli- cations, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems.     

Nonlinear Adaptive Slewing Motion Control of Spacecraft Truss Driven by Synchronous V-gimbaled CMG Precession

The slewing motion control of a truss arm driven by a V-gimbaled control-moment-gyro (CMG) is a nonlinear control problem. The V-gimbaled CMG consists of a pair of gyros that must precess synchronously. The moment of inertia of the system, the angular momentum of the gyros and the external disturbances are not exactly known. With the help of feedback linearization and recursive Lyapunov design method, an adaptive nonlinear controller is designed to deal with the unknown items. Performance of the proposed controller is verified by simulation.     

An SOR Implicit Time-accurate Scheme in Calculating Unsteady Flows

A new time-accurate marching scheme for unsteady flow calculations is proposed in the present work. This method is the combination of classical Successive Over-Relaxation (SOR) iteration method and Jacobian matrix diagonally dominant splitting method of LUSGS. One advantage of this algorithm is the second-order accuracy because of no factorization error. Another advantage is the low computational cost because the Jacobian matrices and fluxes are only calculated once in each physical time step. And, the SOR algorithm has better convergence property than Gauss-Seidel. To investigate its accuracy and convergency, several unsteady flow computa- tional tests are carried out by using the proposed SOR algorithm. Roe’s FDS scheme is used to discritize the inviscid flux terms. Un- steady computational results of SOR are compared with the experiment results and those of Gauss-Seidel. Results reveal that the numerical results agree well with the experimental data and the second-order accuracy can be obtained as the Gauss-Seidel for unsteady flow computations. The impact of SOR factor is investigated for unsteady computations by using different SOR factors in this algorithm to simulate each computational test. Different numbers of inner iterations are needed to converge to the same criterion for different SOR factors and optimal choice of SOR factor can improve the computational efficiency greatly.