【作者】 金义；

【导师】 何小民；

【作者基本信息】 南京航空航天大学 ， 航空宇航推进理论与工程， 2013， 博士

【摘要】 驻涡燃烧室（Trapped Vortex Combustor，简称TVC）是一种非常有发展潜力和应用前景的新概念燃烧室，目前的试验结果证明了其优于常规旋流稳定燃烧室的性能：火焰稳定范围宽、燃烧效率高、氮氧化物排放低等，驻涡燃烧室也因此成为未来军用航空发动机高油气比燃烧室发展的重要方向之一。本文结合试验研究和数值模拟研究，基于高油气比驻涡燃烧室开展了燃烧室气动方案、油气方案、结构方案设计，并就燃烧室气动特性、部分关键技术和燃烧性能开展了系统而深入的研究。应用粒子图像测速技术和数值计算方法获得了燃烧室冷态流场宏观特性及细节特征。结果表明，凹腔流动的两种典型模式同时存在于本文设计的燃烧室中，联焰板截面为单涡模式，联焰板中间截面为双涡模式；不同截面凹腔与主流掺混的机理和程度不同，这种差异也增强了流动的三维特性；本文研究参数范围内，流动已经处于自模状态，燃烧室进口马赫数的变化对燃烧室流动结构没有影响，马赫数升高，火焰筒内涡量增大，混合增强；对于本文高油气比驻涡燃烧室，standard k-ε湍流模型对流场的预测精度最高。开展了驻涡燃烧室进气结构和供油技术的研究。提出了一种被动流动控制方法优化凹腔流动，数值结果表明，在凹腔前壁进气缝中设置局部阻塞区可以在凹腔内诱导流向涡，增强凹腔流动的三维特性，强化混合。对联焰板结构的研究发现，联焰板的宽度、倾角等结构参数以及联焰板与凹腔前壁进气的匹配对凹腔内的流动、燃烧影响很大，是驻涡燃烧室设计中的两个关键因素，本文获得的联焰板最佳宽度为20mm、最佳倾角0°，凹腔阻塞区位于相邻两联焰板中间对应的燃烧性能最好。研究结果拓展了关于联焰板作用的认识，对驻涡燃烧室设计具有一定的指导意义。提出了部分预混预蒸发多点供油的主燃级供油方案，开展冷态试验获得了钝体空腔孔径、面积比等结构参数以及进口马赫数等对性能的影响，开展燃烧试验初步验证了该方案的可行性。完成了值班级离心喷嘴油雾特性对凹腔燃烧性能的影响试验，获得的最佳油雾锥角为60°，试验结果表明，空心油雾锥性能优于实心油雾锥。开展了常压进口条件仅凹腔供油和凹腔/主燃级同时供油两种模式下燃烧室燃烧性能的试验研究，获得了进口马赫数、总油气比、两级燃油分配等参数对燃烧性能的影响规律。结果表明，473K进口温度下燃烧室贫油熄火油气比最低为0.0042，两级同时工作模式下燃烧效率最高为99.8%，在一定程度上解决了高油气比燃烧室贫油熄火性能和大状态燃烧效率的矛盾。随着凹腔供油比例的升高（20%～50%），燃烧效率降低。出口温度分布系数变化范围为0.14～0.18。本文研究结果对驻涡燃烧室优化设计具有重要指导作用，同时也对高油气比燃烧室的发展具有一定的参考价值。更多还原

【Abstract】 Trapped vortex combustor (TVC) is a very potential and promising new concept combustor forits demonstrated advantages over conventional swirl-stabilized combustors: wide operation range,high combustion efficiency (η) and low emissions. Now, TVC has become one of the most importantcandidates for the future high temperature rise combustor of military aero engine. This paper presentsthe aerodynamic, fuel/air scheme and geometry design of a high fuel/air ratio (FAR) trapped vortexcombustor, as well as numerical and experimental results of aerodynamics, some key technique inves-tigations and combustion characteristics.Particle imaging velocimetry (PIV) measurement and numerical simulation were carried out toinvestigate the cold flow characteristics of the model combustor. The results show that single-vortexand dual-vortex cavity flow patterns were obtained in the radial strut plane and in the middle planebetween two radial struts, respectively. The cavity/mainstream mixing mechanism and mixing degreeof different planes are different, this difference is believed to be helpful in enhancing the three dimen-sional effect of the flow. It is also observed that the flow remains self-similar with the range of inletMach number from0.1to0.25, the vortices become more intense at higher inlet Mach number, whichimplies the ability for the TVC to operate at high inlet velocities. A comparison between the numericalresults and the experimental results demonstrates the superiority of the standard k-ε turbulence modelin TVC flow prediction. The data obtained by PIV measurements in this paper can be used as a benchmark for cold flow CFD simulations of TVC.Key techniques were investigated in terms of flow optimization and fuel supply. A passive flowcontrol technique is proposed to optimize the cavity flow, it is found that streamwise vortexes aresuccessfully induced in cavities by local block area settled in the slots of the cavity fore walls, whichwould result in enhanced heat and mass transfer in circumferential direction. The geometry of radialstrut was varied to check its effect on TVC performance, the results reveal that the geometry of radialstruts has very strong impact on flow field and combustion characteristics of cavities in addition to itsimpact on "flame transportation", the optimum width and inclination angle are20mm and0°respec-tively in present work. Also, the relative position of radial struts and cavity injectors in circumferentialdirection are proved to be a critical issue in TVC, the best performance was achieved when a radialstrut was located in the middle plane of two adjacent cavity injector planes. Partially pre-mixedpre-vaporized multi-injection concept was proposed for the fuel injection in main stage of TVC, the effect of hole diameter, the area ratio and the inlet Ma number on performance were investigated ex-perimentally. The feasibility of this fuel injection technique was validated preliminarily by combus-tion tests. It is shown that combustion performance varies nonmonotonicly with increasing spray an-gle of cavity swirl-pressure injectors, the performance curve peaks at the spray angle of60°, also,better performance is observed with hollow spray cone rather than solid spray cone.The combustion characteristics of the high FAR TVC both in cavity-only mode and in cav-ity+main mode were investigated at atmospheric pressure. The lowest lean blowout fuel/air ratioachieved at the inlet temperature of473K is0.0042, which indicates encouraging flame stability. Incavity-only mode, combustion efficiency over98%were obtained for most of the tested cases. In cav-ity+main mode, noticeable decrease of η is observed as the cavity fuel percentage increases from20%to50%, the highest η at the over fuel air ratio of0.04is96.7%, however, a higher value of η can beexpected at realistic engine conditions of higher temperature and higher pressure. The overall tem-perature distribution factor (OTDF) varies in the range of0.14～0.18.更多还原