【作者】 柳军；

【导师】 乐嘉陵；

【作者基本信息】 国防科学技术大学 ， 力学、流体力学， 2004， 博士

【摘要】 本文工作主要涉及高超声速热化学非平衡流及其辐射特性的实验和数值计算研究。 实验研究工作为：1)、使用中国空气动力研究与发展中心(CARDC)再入物理弹道靶设备和脉冲曝光时间5ns的Nd-YAG激光器，进行了高超声速钢球模型激波脱体距离的测量实验。在国内第一次得到了非平衡流无烧蚀激波流场清晰的有限条纹激光干涉照片和阴影照片，测量得到高精度的头部激波脱体距离。测量误差约为5％，模型飞行速度5.0～5.5km／s，靶压10～80mmHg。使用了CFD及CFI技术辅助设计和确定实验方案。2)、测量了多个状态的高超声速球模型非平衡流场的可见光辐射强度，并对实验技术和方法进行分析研究。测量采用双狭缝式可见光辐射计，中心波长位于绿光波段(517.8nm、519.8nm)，半宽度为6.6nm。球模型飞行速度为4.8～5.7km／s，靶压10～80mmHg。 数值研究工作包括了热化学非平衡流场及其辐射特性的计算。其中，热化学非平衡流数值模拟工作为： 1)、对热化学非平衡流的物理化学模型进行分析，选择Park双温度模型、Gupta空气11组元化学反应模型及相应的输运模型、振动离解耦合模型、能量交换模型耦合Navier-Stokes方程组求解流动问题。2)、对NND格式、Roe格式、AUSM类格式以及相应的数值计算技术(包括加速收敛技术、MUSCL插值方法、熵修正技术、源项对角隐式处理等)在轴对称、三维热化学非平衡流数值模拟中的应用进行了比较和分析。结果表明，AUSM类格式性能最优，LUSGS隐式处理方法计算效率较高。提出了一种新的熵修正方法，与网格无关并可减少对边界层解的影响。3)、编制完成包含上述物理化学模型及数值技术的热化学非平衡流计算程序TCNEQ(2D、3D)。程序具有良好的结构网格适应性及模块化程度，气动力及热流计算结果与文献吻合，通过了算例考核及实验验证。4)、在国内第一次进行了球模型激波脱体距离实验和计算的高精度对比研究，并使用CFI技术进行了全流场的实验验证。采用多种气体模型计算实验状态的球模型激波脱体距离，并采用CFI技术处理为阴影图和有限干涉条纹图，直接与实验照片对比进行流场验证。5)、采用TCNEQ3D程序对Apollo飞船返回舱大攻角全流场(含底部及近尾流区域)进行数值模拟；计算了返回舱气动力系数，并与文献及实验结果进行对比；分析表明，非平衡现象可能是造成返回舱飞行实验数据与风洞实验数据不一致的原因之一。国防科学技术大学研究生院学位论文 热化学非平衡流辐射特性的数值计算工作有如下部分: 1、根据热空气辐射的三种类型，综合了量子力学、原子分子物理学以及光谱学的相关知识，分别对空气组元的连续谱辐射、原子线辐射和分子带辐射机制进行了详细的分析和讨论，给出了热化学非平衡态下求解辐射发射系数和吸收系数(含诱导辐射)、的相关公式。以本文实验状态为算例条件，在求得热化学非平衡流场数值解的基础上，采用“逐线计算”的精细辐射模型，在波长ZOOOA~S0000A的范围内对原子、分子跃迁各机制详细计算辐射的谱发射系数和谱吸收系数。 2、发展了精细光谱辐射模型的计算与应用分析技术，编制了适用于弹道靶高温气体辐射研究的“辐射计测量数值模拟程序”，在国内第一次应用于弹道靶光辐射实验的分析研究。通过构造规则的“辐射计算网格”，进行三维空间的数据重构，并数值积分求解辐射输运方程(Radiative Transfer Equation)，实现了弹道靶模型光辐射测量过程的数值模拟。计算可以得到流场光辐射信号在模型穿越辐射计视场范围时的完整时间历程，从而实现了可见光辐射实验测量与数值计算的高精度对比。计算并分析了半阴影区和壁面温度对测量结果的影响程度，模型可见光辐射数值计算结果与实验测量数据基本一致。 综合上述研究工作，分别完成了热化学非平衡流场数值模拟程序TcNEQ(2D、3D)、高温空气光谱辐射特性计算程序、高超声速模型流场光辐射信号计算程序，三个部分形成了一套完整的、功能齐全的高温气体动力学计算分析软件系统。其中，TCNEQ系列程序可以选择采用各种数值计算技术，应用于不同热化学模型、复杂外形飞行器的全流场数值模拟和气动力、气动热计算与分析;高温空气光谱辐射特性计算程序和三维流场光辐射信号计算程序可以对飞行器本体及绕流场的光辐射特性进行计算与分析。该软件系统在飞行器外形设计、目标识别与跟踪、通讯、突防、流场特性研究等方面都可发挥作用。流场光辐射信号计算程序经过改进，也可以应用于其他实验设备(如激波管)的高温气体辐射特性研究，对相关实验方法的设计、实验结果的分析整理及型号工程应用有重要的实用意义。关键词:高超声速，热化学非平衡，辐射，数值模拟，弹道靶实验第Xll页更多还原

【Abstract】 This paper is mainly about experimental and numerical study of hypersonic thermochemical nonequilibrium flow and its radiation characteristics. Experimental research includes:l).Highly accurate shock wave standoff distance of the hypersonic spherical steel model has been obtained in China Aerodynamics Research and Development Center (CARDC). The main facilities used are the Reentry Physics Ballistic Range and a high performance, pulsed Nd-YAG laser with pulse duration of 5ns. It is the first time in China to have obtained the clear laser interferogram and shadow graphs of the thermochemical nonequilibrium flowfield around the model without ablation. The error of measurement is about 5%. The model’s flight velocity is 5.0~5.5km/s, and the chamber’s pressure is 10~80mmHg. Computational Fluid Dynamics (CFD) and Computational Flow Imaging (CFI) methods are used to design and determine the experiment’s scheme.2).The radiant intensities of the nonequilibrium flowfield of the hypersonic spherical model in visible light have been obtained under several conditions, and the experimental techniques have been analyzed. A double-slit visible-light radiometer is used with the central wavelength located in the band of green light(517.8nm and 519.8nm) and the half-width 6.6nm. The model’s flight velocity is 4.8~5.7km/s, and the chamber’s pressure is 10~80mmHg.Numerical research includes the computation of thermochemical nonequilibrium flowfield and its radiation characteristics.The research on numerical simulation of thermochemical nonequilibrium flow includes:1). Analyzing the physical and chemical models for thermochemical nonequilibrium flow. The Park’s two-temperature model, Gupta’s reaction model with 11 air species and related transportation model, vibration-dissociation coupling model and energy exchange mechanisms are chosen to solve the Navier-Stokes equations.2).Comparing and analyzing the NND scheme, Roe scheme, AUSM-family scheme and related numerical techniques(including the technique for speeding up convergence, MUSCL method, entropy fix method, diagonal implicit processing of source terms, etc.) in simulating thermochemical nonequilibrium flow. The result indicates that the AUSM-family scheme is the best while the implicit LUSGS method has the highest computational efficiency. This paper also puts forward a newentropy fix method, which is independent of the computational grid and is capable to minimize the dissipative effect in the boundary layer.3).The computational codes TCNEQ (2D, 3D), which are for axial symmetrical and three-dimensional flow, have been established by using the above-mentioned physical and chemical models. The codes have good adaptability with structured grids and high level of modularization. The computational aerodynamics and heat flux are consistent with those of the references and the codes have been validated using experimental data.4).It is the first time in China that high accurate comparative research between the experimental and computational shock wave standoff distances is carried out. Several air models are used in computation. The whole flowfield is experimentally validated using CFI method. With CFI method, the numerical results are processed to generate computational shadowgraphs and finite-fringe interferogram, which can be compared with the experimental photos directly.5).The three-dimensional code TCNEQ3D is used to simulate the whole flowfield around the reentry capsule of the Apollo spacecraft (including the base and wake flow). The aerodynamic coefficients of the capsule are calculated and compared with the references and experimental data. The analysis indicates that the nonequilibrium phenomenon is possibly one of the reasons for the discrepancy between the capsule’s flight data and the wind tunnel data.The research on numerical computation of the radiation characteristics of thermochemical nonequilibrium flow includes:1. On the basis of the three types of the high temperature air radiation, analyzing and discussing in detail of the mechanism of continuum, atomic lines and m更多还原