涡轮基组合循环发动机一体化性能数值模拟

【作者】 范静；

【导师】 乔渭阳；

【作者基本信息】 西北工业大学 ， 人机与环境工程， 2005， 硕士

【摘要】 本文的工作是根据国家863计划关于发展天地往返运输系统的要求,立足于国内现有的计算条件,从一体化角度出发,对空天飞机/吸气式推进系统性能进行系统的研究。 本文分析了吸气式组合发动机的布局方式,对涡扇发动机和冲压发动机的主要设计参数的选择方法进行了说明。为了数值模拟空天飞机/吸气式推进系统一体化性能,采用了模块化合成程序。根据选定的发动机设计参数,计算了沿飞行轨迹的涡扇和冲压发动机的性能。 空天飞机的推进系统中,涡扇和冲压发动机燃烧室、喷管内的温度较高,应该考虑化学平衡效应对发动机性能的影响,因此本文发展了一种快速、稳定的计算化学平衡影响的程序,克服了采用牛顿—莱普森法求解非线性方程组既耗时又存在稳定性方面的缺点。在此基础上,发展了计算有关燃烧、膨胀等热力过程混合气体性质的子程序,与计算发动机循环性能的主程序结合,完整地分析了空天飞机推进系统中的化学平衡效应。 对于高度一体化的飞行器,飞行器的性能与进气道和喷管的内部特性、外部特性有着直接的联系,在一体化设计过程中,确定进气道、喷管的特性是非常重要的。由于目前在微机上采用CFD方法模拟飞行器机体—进气道—发动机—喷管一体化是不现实的,因此本文用工程计算的方法完成了进气道和喷管外部特性的计算。这种方法虽然不能揭示流动的本质,但是可以方便地进行飞行器/推进系统一体化的数值模拟,在飞行器设计的初级阶段是卓有成效的。 由于空天飞机/吸气式推进系统的高度一体化特性,造成了计算时气动和推进界面的划分常常模糊不清。正是由于气动—推进界面定义的模糊,在力的合成过程中,有时出现阻力被遗漏或重复计算,其结果是飞行性能估算不准。因此本文也详细说明了气动—推进界面的划分和力的合成方法,并根据这种方法,计算了推进系统的安装性能。更多还原

【Abstract】 According to the requirement of the aero-space plane project of "863", the integrated performance of an aero-space plane/air-breathing propulsion system is studied systemically in this dissertation.The arrangement of turbo and ramjet engines is described. Choices of main design parameters of turbo and ramjet engines are introduced. For the integrated performance simulation of the aero-space plane/air-breathing propulsion system, a modular synthesis program is used. Based on given design parameters, the engine performance is computed along flight trajectory.On account of high temperature in burners and nozzles of both turbofan and ramjet engines, the effect of chemical-equilibrium on engine performance should be considered. A quickly convergent algorithm is developed to solve this problem. Based on this algorithm, some new routines for calculating combustion and expansion are developed to serve as interfaces between engine program and chemical-equilibrium routines. With these routines, the effect of chemical-equilibrium on the performance of propulsion system is calculated.On account of high temperature in burners and nozzles of both turbofan and ramjet engines, the effect of chemical-equilibrium on engine performance should be considered. A quickly convergent algorithm is developed to solve this problem. Based on this algorithm, some new routines for calculating combustion and expansion are developed to serve as interfaces between engine program and chemical-equilibrium routines. With these routines, the effect of chemical-equilibrium on the performance of propulsion system is calculated.Because the vehicle performance is closely relative to characteristics of induction system and exhaust system for highly integrated vehicles, it is important to determine the characteristics of the induction system and exhaust system. It is unrealistic to simulate the integration of airframe, induction system, engine and exhaust system with CFD algorithm, so an engineering method is used to compute the characteristics ofinduction system and exhaust system. Although this method can’t discribe complicated flow phenomenon exactly, it can easily simulate the integration of vehicle/propulsion system. The engineering method is effective in predesign. For understanding complicated flow near nozzle/afterbody, an effective CFD code(NND scheme) is applied to simulate flow phenomenon near nozzle/afterbody. The results indicate that the model and numerical algorithm is effectiveBecause of highly integration of aero-space plane/air-breathing propulsion system, the definition of aero-propulsion interface is ambiguous, this cause incorrect force accounting, so the definition of Aero-propulsion interface and the approach of force accounting are described in the dissertation . According to the approach of force accounting, installation performance of propulsion system is calculated.更多还原