航空学报英文版

研磨盘表面形貌对研磨效率的影响 =Effect of lap surfaceprofile on lapping efficiency/左敦稳 (南京航空航天大学 ) ,王珉 ,Touge Mutsumi(日本国立熊本大学 ) .-1 999,1 2( 2 ) .-1 1 5～ 1 2 0电子元化、材料加工的高效精密、超精密加工在生产中倍受关注 ,分析了研磨盘表面形貌中研磨效率的影响 ,并通过在研磨盘表面上加工出微小环槽实验研究了研磨铁氧体材料时效率的变化趋势。理论分析和实验结果表明 ,研磨盘表面形貌通过影响对固定磨料和游离磨料的保持能力从而在加工中对效率产生显著影响 ;在加工 Mn-Zn铁氧体材料时在获得同等最…     

在双盘平面研磨机上研磨零件外径的影响因素

在现代飞机制造中,研磨是精密零件加工的重要手段之一。本文仅对在双盘平面研磨机上研磨零件外径的影响因素,并用数理统计分析的方法加以总结,供大家参考。一、在双盘平面研磨机上研磨零件时的影响因素 1.研磨盘的旋转速度研磨时所采用的速度取决于被研磨件的材料、硬度、直径和表面质量,在中型研磨机的上研磨盘有三种速度,即30、60、120转/分,     

高陡度光学非球面高效制造的探讨

分析了计算机控制光学表面成形法、计算机控制应力盘抛光、磁流变抛光制造光学非球面元件的几项先进技术,探讨了光学元件的高速、高效加工,提出了高陡度光学非球面的固着磨料研磨加工。     

瑞士高精度研磨设备

研磨和抛光是一个非常有前景、有成效的精加工方法。瑞士STAHLI公司是一家一直致力于研磨、抛光技术和设备研发和制造的厂家,该公司总部设在瑞士,在德国和美国都设有分厂,是单端面、双端面机床的制造世家。 研磨,是两个表面在一起摩擦的一种加工方法,表面之间有研磨介质(研磨液和研磨料),工件材料被载体表面(磨盘)和压在磨盘上的工件之间无数的松散的粒子磨去。研磨需要     

自适应端齿研磨机的设计与工艺研究

为提高端齿盘研磨精度和研磨效率,从分析端齿盘加工需求出发,改进现有研磨工艺,介绍了一种自适应找正的专用高精度、高效率端齿研磨机床的总体设计方案及其关键零部件,并通过试验验证研磨加工的端齿盘分度精度达到0.5″,能够满足端齿盘研磨加工的要求。     

非接触式超精密研磨技术

名古屋工业技术研究所SP46型非接触式研磨机,研磨盘与工作轴以20～200r/min的转速作同向、高精度旋转,工作悬浮在研磨盘上,在研磨液的化学作用及微细粉末粒子的撞击下产生研磨作用。轴系皆采用液体动静压轴承,可加工Φ170mm的工件。该机可加工出表面粗糙度为2nm的硅片,加工Φ100mm、厚度为30mm的BK7光学玻璃,平面度为0031μm,表面粗糙度(均方根偏差)可达0.0038μm。特别适合微电子功能材料及光学平面的超精密加工,具有广阔的应用前景。     

提高工效的超精密镜面磨削加工

提高工效的超精密镜面磨削加工日本理化学研究所与有关单位合作开发出应用电解在线修整法（ＥＬＩＤ）的超精密镜面磨削系统．它是对由化学气相沉积制成的非球面碳化硅反射镜同时进行表面粗糙度和形状加工，可使加工时间比用传统的研磨加工大大缩短．实验证实加工直径２０...     

不锈钢镜面的游离磨粒精密加工

利用游离磨粒加工方法对马氏体平面不锈钢SUS440C试件进行精密加工.通过田口实验方法对研磨阶段的工艺参数进行了优化,涉及的工艺参数包括研磨盘转速、加工载荷和加工时间.利用优化的研磨工艺加工后试件表面粗糙度达Ra72nm.抛光过程中使用聚氨酯抛光垫和二氧化硅磨粒,经抛光后试件表面粗糙度达Ra8nm、表面呈镜面.     

实现高效率低损伤研磨加工的磨料优化研究

大功率激光系统对于熔石英光学元件提出了苛刻的加工要求,研磨作为加工环节之一,对于光学元件的加工周期和损伤控制具有非常重要的作用。采用计算机控制小磨头方法进行研磨加工时,在加工工艺参数相同的条件下,磨料是直接决定效率和损伤的关键因素。本文分别从材料去除效率和研磨加工损伤两方面对磨料进行对比分析,通过理论仿真得出磨料的规律特性,再结合实验研究进行规律验证,基于高效率和低损伤进行磨料优化选取,并讨论分别给出粗研、精研的磨料和工艺。     

非球面研磨阶段检测技术的优化

研磨阶段非球面的面形误差将由几十微米收敛到几个微米,适当的测量方法决定了该阶段误差的收敛速度和精度,而非圆对称离轴非球面加工研磨阶段的检测无疑更具难度。本文基于双四阶B样条函数的概念,提出了NURBS曲面拟合模型并用于指导非球面的研磨,同时给出应用实例,验证了该方法的有效性。     

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.