不同结构超声速燃烧斜坡喷注器性能对比研究

为了进一步研究斜坡结构特点对超声速流场混合增强作用,设计了膨胀型和压缩型两种斜坡实验件,并分别进行了火焰传播、纹影及油流谱实验.利用数值仿真的方法对斜坡后压力分布、激波间相互作用以及流向涡的卷起过程进行了分析研究,与实验结果对比一致.最后分析了实验结果与国外相关研究的差异,论证了该设计的两种斜坡喷注器中膨胀型斜坡有更好的自燃及火焰稳定作用.      

变推力发动机仿真计算分析

分析了变推力发动机采用的双调模式,用流量调节器控制推进剂流量。流量定位针栓式喷注器控制喷注压降,保证喷注速度基本不变。根据发动机系统特点建立了主要组件的数学模型,并根据模型进行了仿真计算,最后对发动机前管路流阻影响进行了分析。     

某型先进发动机燃油喷嘴雾化特性的试验研究及火焰筒头部数值模拟

使用相位多普勒粒子分析仪和激光多普勒粒子测速仪系统(PDPA/LDV)等设备测量了某型航空发动机喷嘴的雾化特性,主要包括:喷嘴流量特性,雾化粒度(SMD)和喷雾锥角。应用Fluent软件,对装用该喷嘴的燃烧室火焰筒进行了数值模拟。试验和计算结果得出了一些有价值的结论,对该发动机的燃油喷嘴和火焰筒头部温度场、速度场有深入了解,对其改进提供了重要依据。     

丙酮平面激光诱导荧光技术在喷嘴混合研究中的应用

使用丙酮平面激光诱导荧光技术对喷嘴的混合特性进行了研究,分析了示踪粒子及激励波长选择时的注意事项,对丙酮的光物理过程进行了初步研究.对直流离心喷嘴进行了6种速度比的气-气混合实验研究,得到了喷嘴下游区域的浓度分布和混合比分布情况,发现喷嘴存在临界混合速度比vr相似文献   

蒸汽引射稠油输送新技术

管线输送是稠油输运的一种主要手段。由于我国一些油田原油粘度高,常温下流动性差,管输需采用特殊工艺。根据粘度随温度沿指数下降的规律,与其它工艺比较,加热输送工艺有更大的潜力。该文提出了一种蒸汽引射直接加热稠油输送的新技术。为研究其有效性,进行了性能分析,并在辽河油田Ф80mm,300m输油管线上进行了现场实验,测量了三种工况下该方法对稠油的温度、压降和含水率的影响。实验结果表明该文提出的方法是可行的。     

进气道低速特性试验技术研究

为了研究多种进气形式进气道的低速稳、动态气动特性,采用引射器引射的方式,在FL 8低速风洞开展了进气道试验技术研究,研制出了进气道试验专用引射系统、流量测量与控制装置、模型支撑连接装置及大迎角试验设备,通过机翼下、腹部和翼根三种进气形式的进气道模型风洞试验对新研制的进气道试验设备和相关试验技术进行了验证。试验结果表明:在零速度和大迎角、大侧滑(α=60°,β=20°)低速来流下,利用多喷嘴引射器引射可以很好地实现各种进气道模型内流场的模拟,保证进气道工作线与发动机工作线相交。     

风兜面积对气冷喷油杆性能影响的数值研究

以某型涡扇发动机加力燃烧室气冷喷油杆为研究对象,在梯形截面的风兜下底和高度不变的情况下,通过改变上底长度得到一系列不同风兜面积的几何模型,综合考虑外流场对气冷喷油杆内部流动和换热特性的影响,对其在巡航状态下进行了流/热/固耦合三维数值模拟研究,获得了不同风兜面积对气冷喷油杆引气率、冷却空气喷口流量分布、壁面平均冷却效果、壁面最高温度的影响规律.结果表明:引气率随风兜面积增大线性增大;喷油嘴凸台周围冷却空气喷口的流量沿气冷喷油杆内冷却空气流向呈二次曲线规律变化,且随风兜面积增大分布趋于均匀;随风兜面积增大,喷油杆、隔热套壁面平均冷却效果线性增大,壁面最高温度降低;有效抑制内涵高温燃气倒灌进入隔热套是避免喷油杆局部高温的关键.      

Experimental study of hydrogen-rich/oxygen-rich gas-gas injectors

Five types of coaxial injectors were investigated experimentally using hot hydrogen-rich gas and oxygen-rich gas, which were respectively provided by a GH2/GO2 hydrogen-rich perburner and a GH2/GO2 oxygen-rich preburner. The injectors were the shear coaxial injector, the oxidizer post expansion coaxial injector, the fuel impinging coaxial injector, the central body coaxial injector, and the shear tri-coaxial injector. The characteristic velocity efficiency and the combustor＇s wall temperatures were obtained for different design parameters through the experiments. It can be con- cluded that angles of the oxidizer post expansion and the fuel impinging have little influence on the combustion performance and the wall temperatures. The contact area between fuel and oxidizer and the mass flow rate have significant impacts on the combustion performance. The shear tri-coaxial injector has the best combustion performance but also the highest wall temperatures among the five types of injectors.     

针栓式喷注单元雾化角模型分析

为了实现不同径向孔形的针栓式喷注器雾化角的准确预测，从动量守恒方程出发建立了液膜撞击液膜和液膜撞击液束的雾化角理论修正模型。对于液膜撞击液膜的喷注单元，模型中通过理论推导引入了2个变形因子，将撞击的几何变形效应与雾化角关联；对于液膜撞击液束，通过引入阻塞率定义有效撞击动量比，同时将液束入口孔形的影响隐含考虑在变形因子中，最后根据高速摄影试验结果和数值仿真结果获得了对应的变形因子组合系数，使得新的雾化角模型适应性更广、准确性更高。结果表明：引入变形因子和阻塞率的理论模型预测值与试验及数值仿真结果吻合很好；对于液膜撞击液膜，变形因子基本维持在0.9~1.1，根据试验结果及仿真结果，变形因子推荐值为C₁=0.99和C₂=1.06；对于液膜撞击液束，变形因子推荐值为C₁=0.75和C₂=1.25。该模型根据实际出口的轴向动量和合成总动量计算雾化角，隐含考虑了撞击作用造成的影响，较根据撞击前入口的轴向动量和合成总动量计算雾化角的常用模型预测值准确度显著提高，为针栓式喷注器的理论研究和工程设计提供了重要参考。     

A high-fidelity design methodology using LES-based simulation and POD-based emulation: A case study of swirl injectors

Engineering design is undergoing a paradigm shift from design for performance to design for affordability, operability, and durability, seeking multi-objective optimization. To facilitate this transformation, significantly extended design freedom and knowledge must be available in the early design stages. This paper presents a high-fidelity framework for design and optimization of the liquid swirl injectors that are widely used in aerospace propulsion and power-generation systems. The framework assembles a set of techniques, including Design Of Experiment (DOE), high-fidelity Large Eddy Simulations (LES), machine learning, Proper Orthogonal Decomposition (POD)-based Kriging surrogate modeling (emulation), inverse problem optimization, and uncertainty quantification. LES-based simulations can reveal detailed spatiotemporal evolution of flow structures and flame dynamics in a high-fidelity manner, and identify important injector design parameters according to their effects on propellant mixing, flame stabilization, and thermal protection. For a given a space of design parameters, DOE determines the number of design points to perform LES-based simulations. POD-based emulations, trained by the LES database, can effectively explore the design space and deduce an optimal group of design parameters in a turn-around time that is reduced by three orders of magnitude. The accuracy of the emulated results is validated, and the uncertainty of prediction is quantified. The proposed design methodology is expected to profoundly extend the knowledge base and reduce the cost for initial design stages.