【作者】 金亮；

【导师】 王振国；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2008， 博士

【摘要】 论文结合风洞实验与数值模拟方法,对基于升力体构型的高超声速飞行器机体/发动机一体化设计与性能分析方法进行了研究。在借鉴国内超燃冲压发动机研究成果的基础上,完成了高超声速一体化飞行器基准构型的设计,在发动机关闭和发动机通流状态下开展了缩比模型风洞实验,并结合数值模拟方法,对基准构型在发动机关闭状态和通流状态下的流场特征以及纵向气动性能进行了研究。计算结果与实验结果基本吻合,验证了数值计算技术的可靠性。采用数值模拟方法研究了不同模型尺度以及来流条件对飞行器气动性能的影响,分析了风洞实验条件与飞行条件下数值模拟数据产生差别的原因,指出了发动机通流状态下摩阻系数的不同是导致二者产生差别的主要原因。发展了一套模拟超燃冲压发动机燃烧流场的计算程序ChemTur3D,考虑了湍流与与化学反应非平衡效应以精确模拟氢/空气混合与燃烧。该程序数值求解三维RANS方程,采用有限体积法离散计算域。反应模型采用七组份八方程,湍流模型采用Menter提出的SST湍流模型,对流项采用AUSM+以及二阶MUSCL格式求解,粘性项采用中心差分格式求解,应用LU-SGS以及点隐式方法进行时间迭代。在MPICH环境下实现了并行计算,通过相关算例验证了程序的可靠性。数值模拟了直连式超燃冲压发动机以及飞行器基准构型的燃烧室/尾喷管一体化燃烧流场,对燃烧室内的流场特征进行了分析。根据飞行器一体化算力体系划分方法,结合气动数据与推进数据,对飞行器基准构型在发动机点火状态下的性能进行了研究。结果表明,飞行器基准构型在攻角小于3度时可以产生净正推力,但存在配平攻角较大等缺点。在冷流状态下,进行了不同部件构型设计对飞行器整体性能影响的研究,发现机身上表面构型采用卡门曲线设计,可增加低头力矩,有利于配平前体下表面产生的较大抬头力矩。在点火状态下,针对不同燃料混合增强装置、不同燃料喷注位置及当量比对飞行器整体性能的影响进行了研究。将以上研究成果应用于飞行器优化构型的设计,优化构型的容积比基准构型增加16%,通过采用数值模拟方法对优化构型在三种工作状态下的性能进行研究,表明优化构型的配平攻角较小,综合性能较优。论文为研究高超声速飞行器在真实飞行中不同工作状态转变下的性能变化以及一体化构型设计奠定了一定基础。更多还原

【Abstract】 The configuration design and performance analysis of an airframe/scramjet integrated hypersonic lifting body vehicle was researched by using the method of numerical simulation and wind tunnel experiments.A baseline vehicle configuration based on the current research of scramjets was designed, the cowl-closed and cowl-open subscale test models have been built and tested in the wind tunnel, and numerical study was performed on the two configurations to examine the flow-field characteristics and longitudinal aerodynamic performance. A reasonable match between the computed and the test data showed that the CFD methodology may be used for further research at flow conditions where no experimental data was available with confidence. The CFD results were used to access effects of model scale and air flow conditions on the vehicle overall aerodynamic performance. It was indicated that the difference of friction drag coefficient of the wall surface was great, which was the main difference of the drag coefficient between full scale model and subscale model and that between wind tunnel test condition and flight test condition when the cowl door was opened.A computational code ChemTur3D was developed to simulate the reacting flows in scramjet engine combustors. To accurately compute the flow of a hydrogen/air mixture and combustion at high temperature, the turbulent and chemical nonequilibrium effects must be taken into account. The 3D Reynolds averaged Navier-Stokes equations and species conservation equations were solved using a finite volume, cell vertex scheme on three-dimension structured grids. Chemical reactions were modeled using finite rate chemistry between hydrogen and air consisting of seven species and eight reactions, and turbulent mixing was modeled using the Menter’s Shear-Stress Transport (SST) approach. The AUSM+ scheme with the Monotone Upwind Scheme in Conservation Law (MUSCL) interpolation and second order central difference scheme were employed for the convection terms and the viscous terms, respectively. The LU-SGS implicit algorithm was used for the time integration, to eliminate the stiffness problem due to chemical reactions and turbulence, a point implicit method was implemented into the LU-SGS method. The code’s implementation of parallel multi-blocking was realized in MPICH environment, and the numerical accuracy was evaluated by applying the program to compute several test cases.The analysis of flow field characteristics of scramjet combustor in direct-connect test and the integration of scramjet combustor/nozzle of baseline vehicle were carried out by using the code ChemTur3D. The performance of the baseline vehicle working at powered mode was evaluated by integrating the data of aerodynamic and that of propulsion accounting to the force accounting system. Results showed that positive thrust of the powered baseline vehicle was obtained at the angle of attack less than three degree, but the trimmed angle of attack was too high.Numerical simulations of different part configurations under cold flow condition have been performed, and the influence of each configuration design on the overall aerodynamic characteristics was analyzed. It was found that the airframe upper surface geometry featured Von Karman curve could provide a nose down pitch moment, which may be propitious to trim the large nose up pitch moment generated by the forebody. The effects of variation fuel mixing enhancement, distribution of fuel injection and equivalence ratio on the combustor performance were studied by numerical simulation under combustion flow condition.Based on these results, several enhancements to the baseline vehicle was adopted and the optimized vehicle was designed and analyzed, the optimized vehicle has a 16% larger capacity than the baseline one. Numerical simulation results showed that the optimized vehicle has a reduced trim angle of attack than the baseline one, and a better overall aerodynamic performance.This work has established a foundation for increasing the knowledge of the aerodynamics and propulsion performance associated with the different working mode of the hypersonic integrated vehicle free flight as well as supporting the highly airframe/scramjet integrated vehicle configuration design.更多还原