侧向控制喷流干扰流场特性数值研究

侧向喷流是导弹在中高空进行姿态控制的重要手段.本文用数值方法求解N-S方程,模拟了二种带侧向喷流控制的喷流与绕流的干扰流场.通过定性流场结构和物面压力分布与实验结果的比较,数值模拟能较好地模拟侧向喷流与外流干扰产生的复杂流场特性.给出了合理的流场结构和干扰气动力特性,表明数值方法可以作为型号侧向喷流控制设计的研究手段.     

一种结合壁面模型模拟湍流流动的间断界面浸入边界法

提出了一种具有鲁棒性的间断界面浸入边界法，用来模拟不可压湍流的物体绕流问题。开发了一种新的OpenFOAM求解器，该求解器结合了压力隐式分裂算法和k-ωSST湍流模型求解Navier-Stokes方程。为了减少对近壁面网格的要求，在实施边界条件时，采用壁面模型计算得到的壁面剪切力将速度和湍流变量修正联系起来。壁面切应力采用远离壁面的镜像点求得，镜像点上流场变量通过反距离线性插值由周围流场信息得到。使用该求解器模拟了平板绕流、NACA0012表面压强和切应力分布、Buice扩散管、圆柱绕流、方柱绕流5个湍流流动问题，本文数值模拟结果与文献结果有较好的一致性，验证了该方法模拟湍流流动的有效性和准确性。     

三维薄翼非对称绕流的跨音速积分方程及其有限元解法

与有限差分法相比,积分方程的有限元解法具有计算工作量小,对计算机容量要求低而又能达到一定的计算精度等优点,但国外的研究尚限于二维翼型。最近,文[4]发展了积分方程的有限元解法并成功地应用于求解三维薄翼跨音速对称绕流问题。在此基础上,本文进一步发展该方法并用于求解三维薄翼跨音速有升力的非对称绕流问题。     

用非结构动网格方法模拟有相对运动的多体绕流

发展了用于模拟有相对运动的多体非定常绕流，并计算由流场决定的外弹道的数值方法。该方法采用非结构动网格，显式NND有限体 格式，求解非定常Euler方程，并耦合了刚体动力学方程，作为例证，计算了俯仰振动的NACA0012翼型绕流，计算结果与实验及文献结果吻合，最后，整个策略用于计算二维机翼－外挂物分离流场，并确定了外挂物下落轨迹。     

欧拉方程多段翼型绕流计算的嵌套网格方法

本文采用嵌合体埋入技术，将主段翼型和襟翼分成两子域，对多段翼型的复杂构型进行了分区迭代求解，在有限体体积离散的基础上，求解欧拉方程计算各子域流场的解，通过各流场的耦合迭代到多段翼型绕流的解，典型的带３０％襟翼ＧＡ（Ｗ）－１翼型算例表明，该计算方法稳定，能较地模拟多段翼型中主段翼型与襟翼交接处的复杂流动现象计算结果与实验值有较好的一致性。     

基于非结构重叠网格的二维N-S方程求解与应用研究

本文发展了非结构重叠网格技术.通过构造任意单元类型网格重叠的网格间边界确定算法、宿主单元搜索算法以及网格间插值算法,把非结构重叠网格推广应用于求解NS方程,并结合湍流模型模拟二维湍流流场.N-S方程的求解采用有限体积法,通量计算采用Osher格式,湍流模型采用SA模型.为验证本文方法的正确性和有效性,模拟了RAE2822翼型和某三段翼型绕流湍流流场,结果表明采用非结构重叠网格模拟复杂外形湍流流场不但网格生成效率高,而且容易推广应用于具有相对运动的非定常问题,具有较高的工程应用价值.     

三维方柱不可压缩绕流的大涡模拟计算

用非定常不可压缩流动求解方法对三维方柱绕流问题作了大涡模拟计算研究.求解程序采用虚拟压缩方法和双时间步的时间推进方案,对流项的差分采用高阶精度的数值差分格式.通过与实验和文献结果比较分析,验证了基于虚拟压缩方法的湍流大涡模拟计算方案对于复杂的三维钝体绕流计算是可行的.     

隐式无网格算法及其应用研究

本文的主要目的在于研究求解Euler方程的隐式无网格算法，并应用于复杂的流场计算。采用无网格算法，计算区域用点云离散代替通常的网格划分；计算点上的空间导数，用当地点云上引入的二次极小曲面逼近。求解的Euler方程用隐式时间后差离散，结合用Roe的近似Riemann解确定通量，并用LU－SGS算法分步计算，数值求解了单翼型或双翼型模拟的复杂绕流。     

正交流线坐标系中计算二维跨音速流的流线迭代法

本文提出了流线迭代法,用以实现文献[7]所提出的正交流线坐标系中的二维定常无粘气体动力学方程组的数值求解。 此方法的基本做法是:从物面起到流场远边界逐条流线地求出流动速度值,同时求出下一条流线的形状;按此方式对全流场进行迭代。迭代的收敛性很好。 用本文方法在零攻角和跨音速绕流的条件下计算了双圆弧翼型、NACA 0012翼型和R.A.E.101翼型。双圆弧翼型结果与实验数据符合较好。钝头翼型结果与其它方法结果相比是令人满意的。     

旋转坐标系N-S方程无网格/网格混合算法

为了模拟涡桨发动机等绕固定轴旋转的桨叶流场,发展了一种求解旋转体非定常黏性绕流的无网格/网格混合算法。算法基于求解旋转坐标系纳维尔-斯托克斯方程展开,避免了旋转角速度特征物理量的插值运算;计算域采用整体网格和物面附近局部无网格离散,通过引入无网格和网格对偶点,实现了混合算法绕流信息的跨区交换,并给出了一种对偶点调整选取的方法;基于无网格点云空间导数逼近方法离散控制方程,并结合隐式LU-SGS算法,给出了混合算法求解非定常问题的双时间步隐式推进格式。结果表明：所提算法通过2维振荡翼型非定常绕流、旋转圆柱黏性绕流和模拟发动机桨叶旋转运动的3维悬停旋翼绕流进行了考核,所得升力系数等重要气动数据的变化趋势与文献试验或计算值一致,典型截面处所示的激波强度和位置亦与文献值吻合,展现出算法在模拟旋转部件绕流问题方面具有广阔的工程应用前景。     

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.