基于遗传算法和空间推进方法的高超声速进气道优化设计研究

将遗传算法（单目标遗传算法GA和多目标遗传算法NSGA-Ⅱ、NCGA）与高效、高精度的卒间推进方法——SSPNS（Single-sweep Parabolized Navier-Stokes Algorithm）流场计算方法相结合，对二维高超声速进气道进行了气动优化设计研究。在单目标优化设计中以巡航点（Ma=7．0）的总压恢复最大为设计目标，多目标设计中则在巡航点分别考察了总压恢复最大-压升最大两目标模型、总压恢复最大-压升最大-阻力系数最小三目标模型。优化设计结果表明，单目标设计使得总压恢复有明显提高；多目标优化设计所得的Pareto最优前沿为设计者提供了可靠的设计依据。为了兼顾巡航点和加速爬升段的综合忭能，采用多目标优化方法对进气道进行了多点优化设计，并开展了基于等动压弹道的设计点选择问题初步研究。计算结果表明，若将设计点选在Ma=6．5左右，则进气道的综合性能较好。     

多道扫描探针系统在电弧风洞中的应用

介绍了一种用于诊断电弧风洞等离子体参数的多道扫描探针系统，使用该系统研究了ＦＤ０４风洞空流场的等离子体特性，利用ＣＴＷ理论分析了探针数据，实时给出了流场攻密度的空间分布。实验表明，空流场的电子温度分布基本是均匀的；电子密度分布与流场结构紧密相关，电子密度变化在３倍之内，随着流场结值的不同２，电子密度也随之变化。     

氢/空气超音速燃烧自燃规律的实验研究

对平行喷射氢／空气超音速燃烧自燃规律进行了实验研究。主流空气用氢和空气燃烧补氧的方式加热到温度1000～2100K，压力0．8～1．6MPa。发现滞止温度、滞止压力和燃烧室内部构型等都对自燃有影响，特别是滞止温度和内壁构型的影响非常大。研究了四种试验段构型的自燃规律，找到了它们的自燃极限条件。对于光滑内壁构型，当温度接近自燃极限时，发现了有兴趣的现象并作了讨论。     

碱金属引射对尾流化学动力学和电子密度的影响

用把碱金属（Na）加入到空气尾流中进行数值模拟的方法,研究了碱金属引射对高超声速尾流化学动力学和电子密度的影响。采用的化学反应模型为包括O2、N2、O、N、NO、NO＋、Na 、Na、O2-及e-的10组元模型。计算结果表明,碱金属引射,使尾流电子数密度增加1～3个量级。计算结果与文献中的数据符合较好。     

高超音速进气道的附面层问题

本文论述了高超音速进气道所面临的严重附层面问题,高超音速附面层的特点,高超音速附面层对进气道性能的影响,影响附面层转捩和厚度的诸因素.对如何控制和改善附面层及在设计高超音速进气道时如何考虑附面层因素,亦提出了一些初步看法.     

二维非常规压缩型面超/高超声速进气道的设计概念

为了提高满足一定尺寸要求的进气道的性能,提出了一种非常规压缩型面进气道,并用数值模拟手段对该进气道和常规的二维斜楔式进气道的性能进行了比较。数值模拟结果表明,设计工况下该进气道能够获得跟常规二维斜楔式进气道大致相当的气动性能。非设计工况下,该进气道性能优于常规进气道。一体化设计时,该进气道对保持前机体来流附面层的稳定性十分有利。     

高超音速飞行的总温总压计算

本文用化学平衡定熵变成份变比热热力计算法(以下称热力计算法〕计算了Ma=0～7.00、高度H=0～40km的总温、总压随Ma数及高度H的变化规律.计算结果与定成份定比热的气动函数法(下称气动函数法)和修正系数法的计算结果及R-R公司的引用数据进行了比较.给出了总温、总压的相对误差δ_T、δ_P随Ma数及H的变化规律.计算表明,热力计算法与气动函数法相比较,在Ma>3.0之后有显著的差别.     

Particle swarm optimization applied to hypersonic reentry trajectories

This paper presents the novel use of the particle swarm optimization(PSO)to generate the end-to-end trajectory for hypersonic reentry vehicles in a quite simple formulation.The velocitydependent bank angle profile is developed to reduce the search space of unknown parameters based on the constrained PSO algorithm.The path constraints are enforced by setting the fitness function to be infinite on condition that the particles violate the maximum allowable values.The PSO algorithm also provides a much easier means to satisfy the terminal conditions by adding penalty terms to the fitness function.Furthermore,the approximate reentry landing footprint is fast constructed by incorporating an interpolation model into the standardized bank angle profiles.Numerical simulations demonstrate that the PSO method is a feasible and flexible tool to generate the end-to-end trajectory and landing footprint for hypersonic reentry vehicles.     

Advances in critical technologies for hypersonic and high-enthalpy wind tunnel

Hypersonic and high-enthalpy wind tunnels and their measurement techniques are the cornerstone of the hypersonic flight era that is a dream for human beings to fly faster, higher and further. The great progress has been achieved during the recent years and their critical technologies are still in an urgent need for further development. There are at least four kinds of hypersonic and high-enthalpy wind tunnels that are widely applied over the world and can be classified according to their operation modes. These wind tunnels are named as air-directly-heated hypersonic wind tunnel, light-gas-heated shock tunnel, free-piston-driven shock tunnel and detonation-driven shock tunnel, respectively. The critical technologies for developing the wind tunnels are introduced in this paper, and their merits and weakness are discussed based on wind tunnel performance evaluation. Measurement techniques especially developed for high-enthalpy flows are a part of the hypersonic wind tunnel technology because the flow is a chemically reacting gas motion and its diagnosis needs specially designed instruments. Three kinds of the measurement techniques considered to be of primary importance are introduced here, including the heat flux sensor, the aerodynamic balance, and optical diagnosis techniques. The techniques are developed usually for conventional wind tunnels, but further improved for hypersonic and high-enthalpy tunnels. The hypersonic ground test facilities have provided us with most of valuable experimental data on high-enthalpy flows and will play a more important role in hypersonic research area in the future. Therefore, several prospects for developing hypersonic and high-enthalpy wind tunnels are presented from our point of view.     

Sensitivity analysis of flowfield modeling parameters upon the flow structure and aerodynamics of an opposing jet over a hypersonic blunt body

Implementation of an opposing jet in design of a hypersonic blunt body significantly modifies the external flowfield and yields a considerable reduction in the aerodynamic drag. This study aims to investigate the effects of flowfield modeling parameters of injection and freestream on the flow structure and aerodynamics of a blunt body with an opposing jet in hypersonic flow. Reynolds-Averaged Navier-Stokes (RANS) equations with a Shear Stress Transport (SST) turbulence model are employed to simulate the intricate jet flow interaction. Through utilizing a Non-Intrusive Polynomial Chaos (NIPC) method to construct surrogates, a functional relation is established between input modeling parameters and output flowfield and aerodynamic quantities in concern. Sobol indices in sensitivity analysis are introduced to represent the relative contribution of each parameter. It is found that variations in modeling parameters produce large variations in the flow structure and aerodynamics. The jet-to-freestream total-pressure ratio, jet Mach number, and freestream Mach number are the major contributors to variation in surface pressure, demonstrating an evident location-dependent behavior. The penetration length of injection, reattachment angle of the shear layer, and aerodynamic drag are also most sensitive to the three crucial parameters above. In comparison, the contributions of freestream temperature, freestream density, and jet total temperature are nearly negligible.