三维机身机翼一体化雷达截面的复射线分析

本文把入射平面波用三维复射线展开，利用复射线近轴近似原理，计算并叠加每个复波束经三维机身机翼一体化的多次反射后而产生的远场散射贡献，从而可以方便地求得目标的雷达截面（ＲＣＳ）。本文还对计算实例作了实验验证。     

Integrated batteries layout and structural topology optimization for a solar-powered drone

The purpose of this paper is to demonstrate an integrated optimization scheme for a solar-powered drone structure. Consider a primary beam in the wing of large aspect ratio, where 100 lithium batteries are assembled. In the proposed integrated optimization, the batteries are considered here as parts of the load-carrying structure. The corresponding mechanical behaviors are simulated in the structural design and described with super-elements. The batteries layout and the structural topology are then introduced as mixed design variables and optimized simultaneously to achieve an accordant load-carrying path. Geometrical nonlinearity is considered due to the large deformation. Different periodic structural configurations are tested in the optimization in order to meet the structural manufacturing and assembly convenience. The optimized designs are rebuilt and tested in different load cases. Maintaining the same structural weight, the global mechanical performances are improved greatly compared with the initial design.     

有无涵道动力下的类BWB低速布局气动特性研究

随着航空飞行器的不断发展,新型非常规气动布局研究早已成为世界航空大国的关注焦点。基于TRIP 3.0软件平台通过等效盘模型应用到涵道风扇内外流一体化模拟中,完成对类BWB低速布局有无涵道风扇动力下的气动特性和流场影响分析。首先,对某单独螺旋桨验证算例进行分析;然后,对单独涵道风扇进行计算,得到设计推力下的涵道动力叶片数、安装角及转速等参数;最后,将设计推力下涵道动力参数应用到类BWB低速布局全机有无动力模拟中。结果表明:计算拉力和扭矩值与试验值吻合较好;尾部布置的涵道动力对机身后段及尾翼压力分布影响显著;涵道对前方气流抽吸作用,加速机身后段上表面气流流速,减小内侧平尾有效迎角,对机身和平尾升力以及俯仰力矩系数影响较大;在小迎角状态下,涵道动力对机身增升作用明显,会产生明显低头力矩,但对平尾作用正好相反,且两者增量大小相当,使得全机增升效果不显著,且俯仰力矩变化较小。     

有无叶顶冷却涡轮叶栅气热性能的旋转效应研究

为揭示叶片或机匣旋转条件和叶顶冷却对涡轮动叶气热性能的影响机理,选用LISA 1.5级涡轮动叶片,构建叶顶冷却孔,开展了不同冷气流量下的数值模拟研究。计算结果表明:不同旋转条件下,当冷气与主流的流量比为0.3%时,叶栅能量损失最低,当流量比为1.0%时,间隙泄漏流量最低、叶顶传热性能最好。叶片旋转、机匣旋转和平移运动都能降低泄漏损失和泄漏流量,叶片旋转时,叶栅出口下游上半叶高截面的能量损失最大降低约26.10%。旋转效应对泄漏损失的影响不随流量比变化而改变,但对叶栅总损失和叶顶传热品质的影响随流量比增加会不同。当流量比小于0.3%时,叶片旋转情况下叶栅总损失低于静止工况但高于机匣运动工况,且叶顶传热品质最优;当流量比大于0.7%时,叶片旋转使叶栅总损失最高,机匣运动使叶顶传热品质最优。     

Transonic wing stall of a blended flying wing common research model based on DDES method

Numerical simulation of wing stall of a blended flying wing configuration at transonic speed was conducted using both delayed detached eddy simulation(DDES) and unsteady Reynolds-averaged Navier-Stokes(URANS) equations methods based on the shear stress transport(SST) turbulence model for a free-stream Mach number 0.9 and a Reynolds number 9.6 × 10~6. A joint time step/grid density study is performed based on power spectrum density(PSD) analysis of the frequency content of forces or moments, and medium mesh and the normalized time scale0.010 were suggested for this simulation. The simulation results show that the DDES methods perform more precisely than the URANS method and the aerodynamic coefficient results from DDES method compare very well with the experiment data. The angle of attack of nonlinear vortex lift and abrupt wing stall of DDES results compare well with the experimental data. The flow structure of the DDES computation shows that the wing stall is caused mainly by the leeward vortex breakdown which occurred at x/x_(cr)= 0.6 at angle of attack of 14°. The DDES methods show advantage in the simulation problem with separation flow. The computed result shows that a shock/vortex interaction is responsible for the wing stall caused by the vortex breakdown. The balance of the vortex strength and axial flow, and the shock strength, is examined to provide an explanation of the sensitivity of the breakdown location. Wing body thickness has a great influence on shock and shock/vortex interactions, which can make a significant difference to the vortex breakdown behavior and stall characteristic of the blended flying wing configuration.     

低速离心压气机叶尖小翼设计与扩稳机理研究

为了揭示叶尖小翼对离心压气机气动性能的影响机理,采用数值模拟方法研究了NASA低速离心压气机(LSCC)附加不同叶尖小翼的气动特性,并在分析离心叶轮失稳机制的基础上探究了叶尖小翼的扩稳机理.研究结果表明:平顶型小翼对离心压气机性能影响较小,凹槽型小翼均使得压气机效率有所降低.凹槽型压力面小翼方案使得压气机综合稳定裕度增...     

雷诺数对涡轮叶尖流场影响的数值研究

采用基于压力修正的三维计算流体力学程序，结合雷诺应力湍流模型和剪切应力传输湍流模型加壁面函数的方法，对某一轴流涡轮转子叶尖间隙流场进行了数值计算研究，详细计算了不同涡轮叶尖间隙高度和来流湍流度条件下雷诺数对涡轮转子间隙流场的影响，最后计算了转子效率。结果表明：当泄漏流流经叶尖时因为叶尖剪切力做功有块总压增大区；雷诺数带来的影响比湍流度和叶尖间隙高度带来的影响要大，湍流度的变化对流场影响不大；雷诺数对泄漏涡尺寸的影响不大，但低雷诺数会引起流动分离，带来损失，当雷诺数在文中的范围内变化时，效率下降近八个百分点。     

叶尖泄漏与压气机叶栅三维角区分离相互作用实验研究

为了进一步揭示叶顶泄漏与压气机叶栅三维角区分离流动的相互作用机制,采用五孔气动探针测量了叶栅出口截面气动参数,并对机匣端壁静压进行了测量,详细分析了不同间隙尺寸及来流角度时压气机叶栅间隙流对角区三维分离流动的影响机理.研究结果表明,适当大小叶顶间隙引入的泄漏流阻止了端壁二次流动与叶片吸力面附面层之间的相互作用,移除了三维角区分离,改善了叶栅性能.随着叶顶间隙尺寸及叶栅内气流折转程度的增加,叶顶泄漏涡与上通道涡间的相互作用程度逐渐增强.     

超薄翼型上液压系统布置的设计分析

超薄翼型飞机后梁空间狭小,无法为液压管路系统提供足够的空间。分别从液压系统泄漏、液压油介质的腐蚀性、穿燃油箱的密封性、对燃油箱温度的影响以及对液压能源系统本身的影响等设计问题进行分析,提出了将部分液压管路布置在燃油箱内的方案。试验证明此设计方案能满足系统要求和适航要求。     

空间平台武器系统传递对准匹配方式

根据建立的传递对准模型和用于导航解算的轨道运动学模型,提出了速度匹配、比力匹配、角速率匹配和姿态匹配等空间平台武器系统传递对准的不同匹配方式,并对不同匹配方式及其组合的传递对准性能进行了仿真分析,研究了弹性变形的影响。结果表明：速度＋角速率和比力＋姿态等组合匹配方式的传递对准性能较优。