涡轮叶片辐照晶体测温安装方式建模及仿真

针对辐照晶体传感器测量复杂工况条件下涡轮叶片表面温度时的安装问题，仿真分析了晶体温度传感器在涡轮叶片上的2种安装方式。选取航空发动机涡轮叶片吸力面的缘板处、叶片尾缘处和气膜孔背面3个位置，模化辐照晶体传感器在涡轮叶片工况下的安装条件，采用表面粘贴和开槽封胶2种安装方式建模，导入ANSYS Workbench进行流-固耦合有限元仿真，分析高温胶和辐照晶体在复杂工况下的应力、变形和温度等特性。结果表明，表面粘贴式安装的晶体传感器温度更高，但高温胶和晶体传感器所受应力远大于开槽封胶式安装所受应力，由此可知表面粘贴式安装的测温精度更高，但其牢固性不如开槽封胶式安装。研究结果可为采用辐照晶体测量航空发动机涡轮叶片温度的试验测试提供基础支撑。     

涡轮叶尖压力边小翼肋条对泄漏流场的数值模拟

结合基于压力修正的采用雷诺应力湍流模型加壁面函数的气维计算流体力学程序,通过在叶尖压力面表面边缘加小翼肋条的被动控制方法以期减小叶尖间隙泄漏流动带来的损失,文章对某一轴流涡轮转子叶尖间隙泄漏流场的被动控制进行了数值模拟研究,并详细分析了在不同肋条宽度下泄漏流场细节,最后计算了涡轮效率;结果表明:涡轮叶尖单压力边小翼肋条总体上减小叶尖表面压差,使得吸力面后半部分泄漏流速度减小,从而减小泄漏流动损失,但会增大通道内流动损失,涡轮转子效率下降;小翼肋条宽度有一个最佳值,小间隙下增大肋条宽度使得效率减小,大间隙下肋条宽度增大却增大涡轮转子效率;压力边小翼肋条改变了叶尖压力边附近的流场,对吸力边附近泄漏流动结构没有大的影响.     

基于热-流-固耦合方法的涡轮叶片数值计算

将流体动力学方法与有限元方法相结合,在定常流场分析的基础上,采用单向和双向热、流、固耦合的计算方法获得了转子叶片在设计工况下的应力和变形情况,并比较了两种方法的计算结果.单向耦合计算中分析了离心、气动、热载荷对叶片应力、变形的影响,并按照斯贝发动机EGD-3应力标准对叶片强度进行了校核.计算结果表明：两种计算方法在涡轮叶片强度分析中是可行的,双向耦合能更准确地反映转子叶片的真实工况.     

某型燃气轮机等离子强化燃烧三维仿真研究

为对某型燃气轮机燃烧室性能进行预估,以提供燃烧室优化设计和试验定型的理论依据,对某型燃气轮机燃烧室等离子强化燃烧流场进行了三维仿真。网格在曲线贴体坐标系下进行非结构化划分,湍流模型采用RNG模型,压力一速度耦合的求解采用SIMPLEC算法,得到了燃烧室流场的点火时间、火焰筒壁面温度及流场温度分布、速度分布和物质分布等情况。仿真结果表明,某型燃气轮机的设计基本满足性能要求,但存在一些问题需要在进一步的工作中改进提高。     

C/SiC复合材料在鼻锥热防护系统中的应用研究

在飞行器防热材料优问题的研究中,高超速飞行器鼻锥面临剧烈的气动加热环境,而目前的常用耐高温合金材料很难满足飞行器的防热设计要求,因而需要对鼻锥结构进行热防护.对鼻锥C/SiC复合材料热防护结构进行了仿真研究.湍流模型采用SST k-ω两方程模型,采用松耦合的耦合方法,对不同C/SiC复合材料厚度的热防护效果进行的研究.研究结果发现采用C/SiC复合材料能够有效地降低内部结构的温度;同时结构内部温降幅度随着复合材料厚度的增加而增加.     

超声速旋转火箭弹气动特性仿真和分析

采用CFD方法,基于剪切应力输运（Shear Stress Transport,SST）湍流模型,求解大长细比卷弧翼火箭弹在超声速情况下的气动力和气动热问题．对火箭弹流场进行数值计算,与实验数据进行对比．采用薄壁模型模拟结构耦合传热,计算在一定海拔和旋转情况下火箭弹的气动加热,并与不旋转的情况进行对比．计算结果表明该数值方法能较好地计算气动力因数和气动热分布．在特定的低转速和海拔情况下的火箭弹温度分布比不旋转的稍微大一点,在旋转情况下的火箭弹尾部截面压力分布不对称,尾部流线更加紊乱;弹头和尾翼前缘温度较高,应当在火箭弹设计中予以考虑．     

汽车发动机冷却风扇仿真方法对比

对比多参考坐标系(Multiple Reference Frame,MRF)模型和滑移网格模型(Sliding Mesh Model,SMM)在分析中的差异,分别应用FLUENT中的三维N-S方程和RNG湍流模型,对发动机冷却风扇的静止和旋转区域进行数值模拟,得到流道内空气的质量流量及风扇叶片表面的压力和速度矢量分布.SMM的结果更接近真实结果;根据SMM得出的结果说明MRF模型在工程领域的应用.     

多管火箭武器的瞬态耦合热效应仿真计算

针对某火箭武器发射时外部高温高速燃气流对控制柜内部换热的耦合加热问题,建立了一种求解多管火箭武器内外耦合热效应的数值仿真方法.为了精确地控制柜内的温度,保证稳定性,通过构造反映壁面外燃气流加热的壁面温度函数,将控制柜外热环境转化为浮动的热边界条件,实现了火箭武器控制柜外部热环境与内部换热的解耦计算,避免了难以实现的直接耦合求解,仿真了多管火箭武器控制柜内外的温度分布,为进一步进行火箭武器控制柜的热可靠性设计提供了依据.     

基于流固耦合的叶片颤振分析

研究航空发动机性能问题,叶片颤振过程属于流固耦合问题,为了对叶片颤振进行预测和分析,保证发动机稳定,在提出对流固耦合原理和求解过程进行分析的基础上,采用 ANSYS 进行结构计算,CFX 进行流场计算,并利用两者间的数据交互平台传递流场压力载荷和结构位移数据,实现了流固耦合数值仿真计算.在不同来流速度及攻角下进行叶片和流场的耦合计算,根据得到的叶片振动位移响应判断叶片是否会发生颤振.计算结果表明,颤振频率与叶片低阶固有频率一致,证明来流速度和攻角是影响叶片气动弹性稳定性的重要因素,并可做为叶片颤振的预测依据.     

基于参数化的涡轮叶片三维气动优化仿真

为了提高涡轮叶片的设计效率,在分析已有涡轮叶片截面线参数化造型技术优缺点的基础上,基于B样条曲线实现了涡轮叶片截面线的参数化造型和参数化修改,并编写了叶片造型程序,实现了叶片流场模型的自动化生成.以某型号涡轮叶片为例,对其进行三维流场数值模拟,然后采用遗传算法和序列二次规划法算法的组合,以涡轮的气动效率为目标函数,对涡轮叶片进行了气动优化.算例结果表明文中所建立的涡轮叶片自动优化设计体系是可行的.     

Reliability based multidisciplinary design optimization of cooling turbine blade considering uncertainty data statistics

Considering the coupling among aerodynamic, heat transfer and strength, a reliability based multidisciplinary design optimization method for cooling turbine blade is introduced. Multidisciplinary analysis of cooling turbine blade is carried out by sequential conjugated heat transfer analysis and strength analysis with temperature and pressure interpolation. Uncertainty data including the blade wall, rib thickness, elasticity Modulus and rotation speed is collected. Data statistics display the probability models of uncertainty data follow three-parameter Weibull distribution. The thickness of blade wall, thickness and height of ribs are chosen as design variables. Kriging surrogate model is introduced to reduce time-consuming multidisciplinary reliability analysis in RBMDO loop. The reliability based multidisciplinary design optimization of a cooling turbine blade is carried out. Optimization results shows that the RBMDO method proposed in this work improves the performance of cooling turbine blade availably.

     

Aerodynamic and heat transfer design optimization of internally cooling turbine blade based different surrogate models

This study presents a numerical procedure to optimize the cooling passage structure of turbine blade to enhance aerodynamic and heat transfer. Surrogate model based optimization technique is used with Navier-Stokes analysis of fluid flow and heat transfer with RNG k-epsilon transport turbulence model. The objective function is defined as a nonlinear combination of heat transfer and pressure loss with K-S function. Optimal Latin Hypercube Sampling is used to determine the training points as a mean of design of experiment. Two Loops Dynamic Optimization System (TLDOS) is performed to implement the cooling blade optimization. Blade performance improves obviously, especially the kriging model based system. Result shows a significant impact of rib positions for blade heat transfer but slightly for total pressure loss. Numerical simulation proves the feasibility and validity of the TLDOS methods.     

Distortion behavior of hydro turbine blade castings during heat treatment processes under variation of seasonal temperature

Distortion often appears at the corners of heavy turbine blade castings during heat treatment processes,so a great machining allowance is generally set in production which directly results in cost increase. In this paper,a novel real-time measuring technology is developed for non-contact measuring the deformation behavior of heavy steel castings in heat treatment process. It was employed to measure the distortion and the temperature field of a batch of heavy turbine blade castings at cooling stage in normal...     

内置转子换热管强化传热数值模拟

为分析内置转子换热管的传热效果,建立光管和内置转子换热管的三维模型,对换热管内流场、温度场、压力场以及传热过程进行模拟,得到管内流体的阻力特性和传热特性.模拟结果表明:内置转子换热管内的三维流动比较复杂,转子与管壁之间缝隙内的流体有明显的环绕流动,切向速度和径向速度也增大到一定范围;相同雷诺数条件下,内置转子换热管压降...     

Implementation of synthetic turbulence inlet for turbomachinery LES

Large eddy simulation (LES) has the potential to model complex separated flows, where Reynolds Averaged Navier–Stokes (RANS) based methods often fail. An important aspect of LES is specifying correlated turbulent fluctuations at the inlet boundary. This is particularly important in turbomachines, where turbulence length scale and intensity play a key role in the correct prediction of component performance.In this work, a method is implemented into an unstructured Computational Fluid Dynamics (CFD) solver to impose correlated turbulent fluctuations in a compressible form. It is shown that compressibility effects are particularly important in turbomachinery and must be taken into account. The method uses a pre-processing method to generate a cube of isotropic, homogeneous turbulence. The velocity fluctuations so obtained are used to determine a fluctuating Mach number in order to evaluate the instantaneous total pressure and temperature fluctuations at domain inlet. In the authors knowledge this is one of the first attempts to define correlated fluctuations in a compressible form.The method is successfully applied to two turbomachinery related flows. Firstly, the jet flow from a propelling nozzle is investigated. Following this, the flow over a low pressure (LP) turbine blade is predicted. Results from the LES simulations show that modifications to the inlet conditions can significantly affect flow development. For the jet, changes in the shear layer and peak shear stress are shown, important in the context of high frequency sideline noise generated by the jet. Despite what is suggested in the literature the differences in shear stresses are important also in a non-swirling jet.For the LP turbine, incoming turbulent fluctuations modify the onset of transition and the extent of separation bubble. Without imposed turbulence fluctuations, loss is overpredicted by up to 50%. Moreover it is important to use a compressible solver. Despite the fact that the majority of the results proposed in literature on LP turbine is using incompressible solvers, the difference in terms of pressure coefficient, Cp, is comparable to turbulence contribution.     

A coupled Navier-Stokes/Vortex-Panel solver for the numerical analysis of wind turbines

The present paper introduces a coupled Navier-Stokes/Vortex-Panel solver for the computational study of incompressible high Reynolds number flow around horizontal axis wind turbines. The Navier-Stokes solver is confined to the near-field around one wind turbine blade; the Vortex-Panel method accounts for the far-field of a two-bladed rotor. A robust coupling between both methods is achieved through the spanwise distribution of bound circulation determined by Stokes’ theorem. The coupled solver reduces both artificial dissipation and computational cost compared to a full-domain Navier-Stokes analysis. Results obtained for inviscid and attached viscous flow around an optimal wind turbine blade are compared to a vortex model based on strip theory. Good agreement is found between both models that serves as a validation of the coupled solver for future applications to wind turbines.     

乙烯裂解炉反应管数学模拟新方法

综述了不同类型的乙烯裂解炉反应管数学模型，分析了各类模型的缺点。为此提出了一种进行反应管数学模拟的新方法。即应用CFD方法对反应管内流体流动、传热、传质及裂解反应过程，不经任何简化直接进行数值求解，得到了管内的流场、温度场和浓度场等详细信息。模拟计算得到了反应管长度方向上的温度、速度、压力和组分浓度的变化规律；在反应管径向上存在着明显的速度和温度分布，而组分浓度变化程度不如速度和温度明显；计算结果为提出结焦抑制方法提供了依据。     

涡轮气冷叶片传热分析数据提取技术研究

涡轮气冷叶片传热管网计算是涡轮气冷叶片传热设计的重要环节,针对涡轮气冷 叶片传热设计需求,提出了涡轮气冷叶片模型传热分析数据提取的方法,具体包括计算单元划 分、流路自动判断、网络图生成和传热数据提取等算法。结合涡轮气冷叶片结构特点,使用UG Open API 工具开发了传热分析数据提取系统,实现了涡轮气冷叶片传热分析数据的提取、管理 和输出功能,以用于后续的分析计算,提高了传热设计管网计算的自动化水平,并通过实例验 证了所提出方法的可行性。     

基于叶片动态响应后风轮输出特性的CFD仿真

通过模态实验测得叶片低阶弯振特征向量,经过Matlab拟合获得风轮振动控制方程。自编UDF代码实现对运行风轮振动形态的控制。数值模拟过程中利用动网格技术施加到风轮叶片,控制其运动形态,使其旋转的同时做垂直于旋转面的弯振运动。湍流模型选择大涡模拟(LES)研究振动风轮输出特性规律。研究结果表明:施加低阶弯振后,叶片中部位置出现压力指向性的改变,扭矩和推力波动明显加剧且呈现出周期性规律。弯振的施加使风轮功率下降,且下降趋势随着风速和尖速比增大而增强。通过仿真叶片的结构动态响应,为改进和优化常规风力机性能分析及流固耦合分析提供新思路。     

A Turbine Blade Parametric Modeling Method Considering 1-D Heat Transfer Analysis

Traditional feature-based turbine blade models can match the needs of geometric modeling but could hardly meet the requirement of data extraction in 1-D heat transfer analysis. In this paper, the requirements of data extraction in 1-D heat transfer analysis are taken into consideration as well as geometric representation in parametric design process. An improved turbine blade parametric modeling method is proposed. Based on the modeling method proposed, a system structure of blade modeling process considering 1-D heat transfer analysis is devised. Eventually, a turbine blade parametric modeling system is constructed to test and verify the feasibility of the proposed modeling method and system structure. Experiments show that the blade parametric modeling method proposed can make geometric models better adapt to the specific requirements of 1-D heat transfer analysis and has certain reference value to the creation of high quality digital models.