多点集中力下高超进气道弹性变几何研究

针对二元高超声速进气道需在宽马赫数Ma为4.5～6.0的范围内工作的要求,探索了一种在多点集中力作用下进气道曲面压缩面弹性可调的变几何方案.通过数值计算,首先对集中力数目的选取进行了研究,发现3个集中力对型面变形更为有效;然后对在3个集中力作用下产生变形的进气道进行了流固耦合分析,结果表明变形型面的静压分布与理想型面的静压分布基本吻合;对其性能进行分析,结果表明:Ma为6.0设计的进气道,变形后在Ma为4.5,5.0流量系数分别达到0.98和1.00,且出口总压恢复系数与未变形的进气道相比基本保持不变.由此说明,多点集中力下弹性可调的变几何方案是可行的,并有助于提高非设计点下进气道的性能.      

不同飞行状态下固体火箭发动机尾喷焰数值研究

为了研究飞行状态对固体火箭发动机尾喷焰的影响,建立了含化学反应项和组分输运项的N-S(Navier-Stokes)控制方程,并采用MUSCL(monotonic upstream-centered scheme for conversation laws) Roe格式的有限体积法进行求解.在此基础上,结合热力计算结果对某固体火箭发动机在不同飞行状态下的化学反应流和单一组分流进行仿真计算.结果表明:初始倾角和第一马赫波节长度随飞行高度的增加而增大,随来流马赫数的升高而减小.同单一组分流相比,化学反应流对第一马赫波节的影响较初始倾角显著.射流轴线温度因飞行状态的不同有较大涨落差异.初始倾角、第一马赫波节由来流总压决定,射流轴线温度由激波结构、复燃效应、来流条件等因素共同决定.      

A low-diffusion robust flux splitting scheme towards wide-ranging Mach number flows

This paper develops a low-diffusion robust flux splitting scheme termed TVAP to achieve the simulation of wide-ranging Mach number flows. Based on Toro-Vázquez splitting approach, the new scheme splits inviscid flux into convective system and pressure system. This method introduces Mach number splitting function and numerical sound speed to evaluate advection system. Meanwhile, pressure diffusion term, pressure momentum flux, interface pressure and interface velocity are constructed to measure pressure system. Then, typical test problems are utilized to systematically assess the robustness and accuracy of the resulting scheme. Matrix stability analysis and a series of numerical cases, such as double shear-layer problem and hypersonic viscous flow over blunt cone, demonstrate that TVAP scheme achieves excellent low diffusion, shock stability, contact discontinuity and low-speed resolution, and is potentially a good candidate for wide-ranging Mach number flows.     

中心进气旋转盘流动与换热的数值研究

本文采用混合长度模型及共轭计算的方法对中心进气转静系旋转盘、腔内的流动与换热进行了数值计算, 并与实验结果进行了比较, 证明混合长度模型对转静系旋转盘、腔的流动与换热的计算是可行的。计算结果显示: 冲击区努赛尔特数最大值不在驻点, 而是偏离驻点一段距离; 随着转速和冷气流量的增加, 盘面换热总体加强。      

高位垂直进气旋转盘流动与换热的实验研究

本文用实验的方法对高位垂直进气转静系旋转盘附近冷气流动与换热特性进行了实验研究, 得到了静盘表面压力、转盘表面温度、局部努赛尔特数的分布及平均努赛尔特数, 并对结果进行了相应的分析。      

中心进气和高位垂直进气转静系旋转盘冷却品质比较

基于实验结果,对中心进气和高位垂直进气转静系旋转盘的冷却品质进行了较为系统的比较,结果发现：虽然两者的备面平均努赛尔特数和无量纲过余体平均温度相差很小,但是从减小径向温差角度看,高位垂直进气具有明显的优势,证明了以前提出的涡轮盘冷却指标应含径向温差的合理性。     

高位垂直进气旋转盘非稳态换热的实验研究

用实验的方法对高位垂直进气的转静系旋转盘在非稳态情况下的流动与换热特性进行了研究,主要研究了冷气流量系数和旋转雷诺数的变化对盘面温度和平均努塞尔数的影响.结果发现:冷气流量的改变对盘面的换热影响非常明显,盘面各点温度随时间的变化率是相同的;旋转雷诺数增加使盘面平均努塞尔数增大,旋转雷诺数变化的方式导致盘缘区域温度随时间的变化率与中心区域的不同.      

多级组合盘的整体结构最优化设计

整体组合盘结构优化设计是单级盘结构优化设计的进一步发展, 它具有广泛的实用价值。本文采用自动形状描述、单级盘有限元强度计算、多级盘优化协调组合和整体组合盘结构优化设计策略, 编制了SODMROD软件, 并给出了计算实例。同时介绍了盘剖面形状描述的基本思路和部分公式以及利用优化方法进行盘、鼓间变形协调计算的部分公式推导。      

抽吸对高超声速内收缩进气道涡流区及起动性能的影响

研究了抽吸位置和开槽形式对高超声速内收缩进气道涡流区和起动性能的影响.数值计算结果表明:在内收缩进气道下洗气流集中区域开槽对减小出口涡流区效果显著,在分离包内开槽可以以较小的流量损失来大幅提升进气道的起动性能.横纵向组合槽即T型槽的综合抽吸效率最高,相对原型进气道,设计点马赫数为6.0时在相对抽吸流量为1.01%时出口总压恢复系数提高了12.8%,畸变指数减小了37%;起动马赫数从5.2降至4.1,自起动马赫数由6.2降至4.8.      

New design of a compact aero-robotic drilling end effector: An experimental analysis

This paper presents the development of a normal adjustment cell (NAC) in aero-robotic drilling to improve the quality of vertical drilling, by using an intelligent double-eccentric disk nor-mal adjustment mechanism (2-EDNA), a spherical plain bearing and a floating compress module with sensors. After the surface normal vector is calculated based on the laser sensors’ feedback, the 2-EDNA concept is conceived specifically to address the deviation of the spindle from the sur-face normal at the drilling point. Following the angle calculation, depending on the actual initial position, two precise eccentric disks (PEDs) with an identical eccentric radius are used to rotate with the appropriate angles using two high-resolution DC servomotors. The two PEDs will carry the spindle to coincide with the surface normal, keeping the vertex of the drill bit still to avoid repeated adjustment and position compensation. A series of experiments was conducted on an aeronautical drilling robot platform with a precise NAC. The effect of normal adjustment on bore diameter, dril-ling force, burr size, drilling heat, and tool wear was analyzed. The results validate that using the NAC in robotic drilling results in greatly improved vertical drilling quality and is attainable in terms of intelligence and accuracy.