Effects of stability margin and thrust specific fuel consumption constrains on multi-disciplinary optimization for blended-wing-body design

Blended-Wing-Body(BWB) configuration, as an innovative transport concept, has become a worldwide research focus in the field of civil transports development. Relative to the conventional Tube-And-Wing(TAW) configuration, the BWB shows integrated benefits and serves as a most promising candidate for future ‘‘green aviation". The objective of the present work is to figure out the effects of the stability margin and Thrust Specific Fuel Consumption(TSFC) on the BWB design in the framework of Multi-Disciplinary Optimization(MDO). A physically-based platform was promoted to study the effect static stability margin and engine technology level. Low-order physically based models are applied to the evaluation of the weight and the aerodynamic performance. The modules and methods are illustrated in detail, and the validation of the methods shows feasibility and confidence for the conceptual design of BWB aircrafts. In order to find out the relation between planform changes and the selection of stability and engine technology level, two sets of optimizations are conducted separately. The study proves that these two factors have dominant effects towards the optimized BWB designs in both aerodynamic shapes, weight distribution, which needs to be considered during the MDO design process. A balance diagram analysis is applied to find out a reasonable static stability margin range. It can be concluded that a recommended stability margin of a practical BWB commercial aircraft can be half of that of a conventional TAW design.     

衣服铺陈的岁月

有着特殊含义的衣服．只生存在某个特定年代的人群的集体记忆中．当记忆的阀门偶然打开．过去的时光就这样带着厚重的灰尘在一件件衣服上铺陈开来。     

基于模拟退火算法预测储层参数

讨论了如何将地震资料、测井信息和先验地质知识有机地结合起来预测储层参数，以便揭示储层内部细节和纵横向变化特征。通过将模拟退火算法与人工神经网络相结合，能够解决非线性全局优化问题，勾画出地震信息和储层参数之间的复杂关系，为储层特征描述和储层横向预测提供提供直观、可靠的地层参数剖面一孔隙度、砂泥质百分含量、含水饱和度及渗透率等剖面。     

彩色氦气泡在风洞试验中的应用

彩色氦气泡流动显示是一极好的新技术。在风洞中应用彩色氦气泡进行流动显示已于1984年3月在哈尔滨空气动力研究所实现了,获得了丰富多采的彩色迹线,摄制了清晰的彩色录象和彩色照片。不久之后,进行了轿车、面包车、高楼、船舵、鱼鳞波表面、细长体、圆柱体、降落伞和各种飞机模型的试验。 本文描述了彩色氦气泡流动显示技术,介绍了在风洞中进行流动显示的一般装置、基本原理和应用。     

中心遥控作业的设计研究

从实际应用经验出发，介绍了遥控作业的编写原则和方法，以规范作业设计过程，约定设计规则，引导编码风格，从而保证遥控作业的正确，可靠，高效，易维护。     

利用星敏感器的卫星自主导航

本课题对利用星敏感器进行卫生自主导航问题作了初步的研究，研究表明，当已知地球大气的星光折射模型，则可利用星光折射的测量或掩星时刻的测量来实现卫生的自主导航，在导航过程中不需要精确的姿态确定，研究报告提出了相应的基本导航算法，讨论了误差的影响，通过数学仿真模拟计算，给出了数值结果，提示了这类导航的若干特点。     

飞行仿真转台混合灵敏度设计

以ET－ⅢA型电动伺服转台为背景，在分析了转台系统的不确定性及其性能指标要求的基础上，利用H∞混合灵敏度方法对转台系统速度环进行了设计，并通过计算机实现控制算法，最终的调试结果满足系统的性能要求，从而验证了设计方法的可行性和有效性。     

Numerical simulation of aerodynamic interaction for a tilt rotor aircraft in helicopter mode

A rotor CFD solver is developed for simulating the aerodynamic interaction phenomenon among rotor, wing and fuselage of a tilt rotor aircraft in its helicopter mode. The unsteady Navier–Stokes equations are discretized in inertial frame and embedded grid system is adopted for describing the relative motion among blades and nacelle/wing/fuselage. A combination of multi-layer embedded grid and ‘‘extended hole fringe" technique is complemented in original grid system to tackle grid assembly difficulties arising from the narrow space among different aerodynamic components, and to improve the interpolation precision by decreasing the cell volume discrepancy among different grid blocks. An overall donor cell searching and automatic hole cutting technique is used for grid assembly, and the solution processes are speeded up by introduction of Open MP parallel method. Based on this solver, flow fields and aerodynamics of a tilt rotor aircraft in hover are simulated with several rotor collective angles, and the corresponding states of an isolated rotor and rotor/wing/fuselage model are also computed to obtain reference solution.Aerodynamic interference influences among the rotor and wing/fuselage/nacelle are analyzed,and some meaningful conclusions are drawn.     

气动-引力辅助转移轨道研究及在星际探测中的应用

借力飞行是减小星际探测任务发射能量和总的速度增量的有效途径,然而,借力飞行前后,探测器速度矢量转角的变化往往受到借力星体体积、质量等因素的影响,而不能达到理想的要求。若在借力飞行中引入气动辅助变轨,即气动-引力辅助转移(AGA),则这一问题可以得到有效解决。现通过对AGA转移轨道的分析,给出了AGA转移轨道设计的拼接条件,此拼接条件是对AGA转移轨道进行设计和分析的重要准则。同时还以探测Ivar小行星为例,提出了一种将绘制等高线图和圆锥曲线拼接相结合的设计AGA转移轨道的方法,并给出了设计探测Ivar小行星转移轨道的参数。数值计算表明:AGA转移方法不但可以降低远程星际探测任务的发射能量和总的速度增量,而且可以找到更多的探测机会。     

机载固体运载火箭能力分析及轨道计算

以我国现有固体火箭发动机为动力装置，以带翼的三级固体运载火箭分析模型为依据，探讨机载火箭发射小型低轨卫星的可行性和现实性。