IMECH-IR  > 高温气体动力学国家重点实验室
高超声速滑翔飞行器静/动态气动特性研究
Alternative TitleStudy of Static and Dynamic Aerodynamic Characteristics of Hypersonic Gliding Vehicle
韩汉桥
Thesis Advisor盛宏至 ; 王发民
2013-04
Degree Grantor中国科学院大学
Place of Conferral北京
Subtype博士
Degree Discipline流体力学
Keyword高超声速滑翔飞行器 乘波体 黏性干扰效应 真实气体效应 静稳定性 动态气动特性
Abstract

高超声速滑翔飞行器是一种可以实现远程快速到达、机动灵活的新型运载器,能够在较宽的飞行速度和高度范围内进行有效载荷精确投放,已成为各军事强国一个新的研究热点。本文选择高超声速滑翔飞行器的静/动态气动特性作为研究内容,围绕气动布局设计、高空物理效应影响以及飞行器的动态气动特性这几个关键问题开展了深入研究和探讨。

首先,针对工程约束进行乘波体的黏性优化设计后得到一种高升阻比乘波布局。在考虑防热、有效体积和静稳定性的要求后进行了工程化改型,构造出一种满足三轴静稳定条件的方案,并保持了较好的气动性能,同时给出了改善静稳定性的理论依据。采用CFD方法研究了黏性干扰效应和真实气体效应对所设计的高超声速滑翔飞行器气动特性的影响,得出了不同构型时黏性干扰效应和真实气体效应对气动特性的影响规律,发现迎风面后部的膨胀区对压心位置的变化规律有较大影响。通过比较分析得到了不同气动力系数对各物理效应的敏感程度,可以为高超声速滑翔飞行器的设计及气动性能评估提供理论参考。

发展了一种高效、精确的高超声速非定常气动力模型—VLPT,该模型在当地流活塞理论的基础上引入有效外形修正,可应用于传统工程方法不适用的高空、高马赫数这类强黏性干扰情况。结合定常N-S方程数值解提出了基于涡量的有效外形判定公式,通过大量二维和三维算例证明该模型在较宽的马赫数、攻角、飞行高度范围内都有良好的适用性,且易用于动态气动特性的分析中,计算效率远高于非定常N-S方程,有较高的工程应用价值。

结合VLPT方法推导了俯仰、偏航和滚转方向单自由度运动的静导数和动导数表达式,通过与非定常N-S方程辨识结果的比较,验证了VLPT方法对动态阻尼导数辨识的可靠性。耦合飞行器自由运动的动力学方程和本文发展的VLPT非定常气动力模型,建立了平衡位置处自由扰动运动的非线性分析系统。通过基于状态空间的时域分析方法来分析俯仰运动,结合特征根分析得到俯仰静导数和阻尼导数对俯仰运动特性的影响规律,并采用CFD/RBD方法进行了验证。

建立了分析飞行器横航向耦合运动特性的数学模型,选取了一组典型滑翔状态,通过状态空间内的时域分析方法分析了不同攻角时的特征根轨迹,得到两种横航向耦合运动的失稳模态,即小攻角时的螺旋失稳运动和攻角变大后的荷兰滚失稳运动。采用CFD/RBD方法对横航向耦合运动进行了数值模拟,验证了理论分析所得失稳运动模态的存在,结合气动参数变化对失稳运动过程进行了分析。最后根据特征根方程,结合判断系统稳定性的霍尔维茨判据,探讨了改善飞行器横航向耦合运动稳定性的基本策略。所得结果可为高超声速滑翔飞行器的进一步改型和控制系统设计提供重要参考。

Other Abstract

Hypersonic gliding vehicle is a new type of launch vehicle that has the capability of rapid long-range reach and maneuvering flight, and it can deliver a load precisely with a large range of velocity and altitude, which make it the research focus in the world’s military powers. Focusing on static and dynamic aerodynamic characteristics of hypersonic gliding vehicle, the key scientific problems such as aerodynamic configuration design, the influence of multi-physical effects at high altitude and dynamic aerodynamic characteristics are studied and discussed in this dissertation.

Firstly, a waverider configuration with high lift-to-drag ratio is designed by means of viscous optimization according to engineering constraints. Considering the requirements of thermal protection, effective volume and static staility, the waverider configuration is modified through engineering-oriented design, which can meet the static stability constraints of three directions along coordinate axis and still maintain good aerodynamic performance. By using CFD method, the influence of viscous interaction effects and real-gas effects on hypersonic gliding vehicles is studied, it is found that the expansion region at the end of the windward side has great effect on position of pressure center. The sensitivity of different aerodynamic parameters for each physical effects is acquired as a reference for configuration design and evaluation of aerodynamic performance.

An efficient and accurate hypersonic unsteady aerodynamic model is then developed (Viscous-corrected Local Piston Theory), which is based on local piston theory with viscous correction, and it can be used in strong viscous interaction conditions at high Mach number and high altitude. A semi-empirical relation for the determination of effective shape for this method is presented based on steady Navier-Stokes equations. Furthermore, a series of two-dimensional and three-dimensional numerical examples with various Mach numbers, angles of attack and operating altitudes for different shapes are provided to validate the accuracy of VLPT. This model can be used in analysis of dynamic aerodynamic characteristics easily and has much higher computational efficiency than unsteady Navier-Stokes equations, so it is valuable in engineering application.

The static derivatives and dynamic derivatives of single degree of freedom are derived from VLPT. Compared with unsteady Navier-Stokes predictions, it is found that the method of VLPT for calculating dynamic damping derivatives is reliable. By coupling the governing equations for free motion of flight vehicles (Lagrange’s equations) and hypersonic unsteady aerodynamic model, the nonlinear system for analysis of free disturbance movement at equilibrium point is established. Applying time-domain analysis in state space, the characteristic roots are obtained and the influence of longitudinal static derivatives and dynamic derivatives on pitching oscillation of hypersonic gliding vehicle is studied, which is validated through unsteady computational fluid dynamics simulation that is coupled to a rigid body dynamics simulation (CFD/RBD).

At the end of this dissertation, the analytical model for lateral and directional coupled motion is also established. After choosing a group of typical conditions in gliding trajectory, the root loci at different angles of attack for different motion models are obtained by means of time-domain analysis in state space. The root loci show that there are two unstable motion models in lateral and directional coupled motion: the spiral motion at small angle of attack and the Dutch roll movement at larger angle of attack. To validate these two unstable motion models, the coupled CFD/RBD method has been used, and then the unstable motions are studied based on variations of aerodynamic parameters. Moreover, some strategies are provided according to Hurwitz criterion for the purpose of improving the stability of lateral and directional coupled motion. The above results can be used as a valuable reference for control system design and further modification of hypersonic gliding vehicle.

Language中文
Document Type学位论文
Identifierhttp://dspace.imech.ac.cn/handle/311007/60946
Collection高温气体动力学国家重点实验室
Recommended Citation
GB/T 7714
韩汉桥. 高超声速滑翔飞行器静/动态气动特性研究[D]. 北京. 中国科学院大学,2013.
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