【作者】 吴先宇；

【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， 2007， 博士

【摘要】 论文采用数值仿真和直连式试验等手段深入研究了超燃冲压发动机一体化流道设计优化问题,并全面地探讨了各设计因素对发动机部件和系统性能的影响。发展了基于替代模型的复杂系统渐进优化流程,比较了多项式响应面、Kriging函数、神经网络等替代模型对高度非线性问题的近似能力和迭代优化效果。在复杂非线性系统的渐进优化中,可同时采用多种替代模型进行迭代,有利于充分利用各替代模型对设计空间近似的优势,提高优化效率。建立了进气道/前体性能评估方法,采用渐进优化方法在全空间和缩减空间内对进气道/前体进行了两轮优化,优化效果比较显著;根据优化中建立的数据库,深入分析了各构型参数对进气道/前体性能的影响,结果表明外罩构型参数和隔离段高度对进气道/前体综合性能有相对较大的影响。建立了直连式试验中燃烧室性能评估方法,通过大规模的直连式试验获得了燃烧室性能改善的燃烧室优化构型及最佳燃料喷注分布,并建立了燃烧室性能关于燃烧室型面扩张角、燃料喷注分布以及当量比的数据库。系统地研究了燃烧室扩张角、燃料喷注分布和当量比对燃烧室性能的影响;比较了改变喷注点喷油分配比例、燃料喷注周向分布、增减凹腔等几种情况时燃烧室性能的变化。设计了具有一定适应性和扩展性的燃烧室控制回路,根据反馈的推力和隔离段交互监控点压强等测量数据,通过可调气蚀文氏管动态调节燃料流量实现了燃烧室推力增益和燃烧室-隔离段干扰控制。建立了发动机/机体流道一体化构型的性能评估方法,采用渐进优化方法获得了在设计状态和非设计状态下性能均有较大改善的优化构型,研究了燃料喷注分布和主要构型参数对发动机性能的影响。论文为深入研究各设计因素对超燃冲压发动机性能的影响、获取关键设计因素、提高发动机性能奠定了一定基础。更多还原

【Abstract】 The issue of the integrated scramjet flowpath design and optimization was studied particularly by means of a new method with numerical simulation and direct-connect test, and the effects of design factors on the performance of the components and engine were discussed comprehensively.A successive optimization process based on surrogate models was developed for complex system optimization. The approximate and iterative capabilities of several kinds of surrogate models including polynomial response surface, Kriging model, and neural network were compared. During the optimization iteration of complex system, better optimization efficiency will be achieved when several surrogate models are adopted at the same time by synthesizing their advantages of space fitness.The parameters were defined to evaluate the general performance of inlet/forebody. Two circles of successive optimization of inlet/forebody were executed on the global space and reduced space respectively with the relative remarkable performance improvement. Then, the effects of configuration parameters on performance of inlet/forebody were discussed in detail according the database built during optimization, and the result shows the cowl parameters and isolater height have more important effect on the general performance of inlet/forebody.The analysis method was developed to evaluate the performance of scramjet combustor in direct-connect test. The optimal scramjet combustor configuration and fuel distribution were obtained by abundant direct-connect tests, and the database of combustor performance were built with respect to the divergence angles of combustor shape, distribution of fuel injection and equivalence ratio.The effects of divergence angles of combustor shape, distribution of fuel injection and equivalence ratio on the combustor performance were studied systemically. The variations of combustor performance were discussed for three cases of altering injection proportions for each injection, the circumferential fuel injection distribution, and adding/reducing cavities.An available and extensible combustor control loop was designed to perform the control of thrust force increment and combustor-isolator interaction by feedback of force and isolator pressure measurements, where the fuel mass flow was regulated dynamically by fuel mass flow control system based on controllable cavitaing venturi.The evaluation method was presented to analyze the performance of scramjet engine/airframe flowpath. The successive optimization of scramjet engine/airframe was executed, and the optimal configuration was obtained with remarkable performance improvement at on-design state and off-design state, further more, the effects of fuel injection distritution and main configuration parameters on the general performance of engine/airframe were discussed in detail.This work has established a foundation to further study the effects of design factors on scramjet performance, to obtain the dominating factors, and to improve the scramjet performance.更多还原