船用燃气轮机变几何动力涡轮大攻角流动特性的三维数值模拟

采用三维数值模拟技术,研究了可调导叶转动导致变几何动力涡轮气动性能变化的流场机理。结果表明,在较小的转角范围内,采用大转折角设计的可调导叶使涡轮处于大攻角运行。在大正攻角或大负攻角下可调导叶级动叶栅流道内的三维分离流场结构及其产生机理有很大差异,而且大正攻角造成的吸力面分离流动更使整个涡轮的效率显著地下降。通过系统的机理分析,提出可调导叶宜采用较小转折角的后部加载叶型,而变几何动力涡轮可调导叶级动叶栅要采用较大负冲角的气动设计原则。     

船用燃气轮机动力涡轮可调导叶级的流场结构

基于耦合求解可压缩Favre平均Navier-Stokes方程及Menter的Baseline（BSL）双方程湍流模型．本文对一个考虑可调导叶设计的船用燃气轮机变几何动力涡轮进行了全流场的三维粘性数值模拟。计算结果表明,采用可调导叶技术,涡轮各级热力反动度发生了明显变化;可调导叶级的流动特性变化更显著影响变几何动力涡轮的气动性能;选取具有良好冲角适应性和跨音速性能的可调导叶是船用燃气轮机变几何动力涡轮气动设计的一个关键技术。由此,根据数值计算结果．重点分析可调导叶级的气动特性及其流场结构。     

变几何燃气涡轮损失模型的分析

根据传统的定几何燃气轮机损失模型，提出了在变几何条件下，如何进行涡轮损失计算的思路，并根据具体实例，对几种常用的损失模型作了比较，给出了一套完整的计算变几何涡轮损失的方法。     

可变几何动力涡轮应用的效果

《Теплознергетика》2006年2月号报导了具有可调节导向器的动力涡轮应用效果的研究结果。     

小偏差方法在变几何燃气轮机性能研究中的应用

为了分析不同涡轮变几何给燃气轮机性能带来的影响,基于小偏差方程提出了一种研究变几何燃气轮机性能的新方法。该方法的计算结果与特性曲线法的计算结果比较表明,新方法的计算精度在绝大多数工况下都可以保证在4%以内,如表2所示。采用该方法的计算结果表明,不同涡轮变几何可以得到不同的效果:高压涡轮和低压涡轮变几何可以很好地调节压气机的工作点,在燃气轮机改造过程中可以起到很重要的调节作用,动力涡轮变几何则可以更好地改善机组的变工况性能。     

变几何燃气轮机性能的计算分析

为了分析不同涡轮变几何时的机组性能,基于小偏差方程提出了一种研究变几何燃气轮机性能的新方法。应用该方法计算了不同涡轮通流面积的相对变化量在±5%时的机组性能,并从理论上进行了分析。分析表明:在简单循环机组中,无论是高压涡轮、低压涡轮还是动力涡轮变几何,对系统经济性的影响都不大,但会影响压气机平衡运行线,其中低压涡轮变几何对低压压气机平衡运行线的影响较大,高压涡轮和低压涡轮变几何对高压压气机平衡运行线的影响较大。     

一种考虑变几何特性的重型燃气轮机建模方法

在传统燃气轮机仿真模型的基础上,对比分析模型计算结果与机组性能试验数据,定量地得到了可转导叶(IGV)开度变化对燃气轮机性能的影响,建立了考虑IGV开度变化对机组性能影响的重型燃气轮机性能仿真模型.结果表明:所建模型的稳态计算结果与试验数据相吻合,正确反映了燃气轮机参数随燃气轮机功率的变化关系,可以应用于系统动态特性分析以及控制系统的设计和验证.     

某MW级燃机变几何动力涡轮动_静叶栅与排气道的流动分析

某MW级燃机末端的变几何动力涡轮动/静叶栅与非对称排气道之间的流场会相互作用,使用商用CFD软件CFX研究了不同导叶安装角下、二者之间的耦合流场.在导叶设计安装角下的流场分析表明:排气道的非周向对称性主要影响动力透平的动叶流场,导致动叶不同叶片载荷出现周向差异,同时动叶出口气流角分布也会出现强烈的周向不均匀性.导叶旋转7°后,导叶进口正冲角增大导致吸力面大范围分离;动叶进口呈现负攻角,压力面的分离程度增大;同时排气道内旋涡程度加剧,这导致了导叶安装角改变后动力涡轮的效率和功率出现明显下降.     

1,5级变几何涡轮非定常流动特性研究

可转导叶由于端部间隙和转轴的存在,会产生复杂的二次流动。本文对LISA涡轮进行变几何改型,采用几何约化法对该1.5级变几何涡轮进行数值模拟,详细探究了可转导叶间隙高度对可转导叶（S1）涡系的流动细节和载荷的影响,并深入研究其非定常流动对下游叶排的干涉及二次流输运过程的影响。计算结果表明：泄漏涡（LV）、角涡（CV）和通道涡（PV）共同组成了可转导叶的涡系;可转导叶端部间隙高度影响流动损失和级效率大小,设计间隙下该变几何涡轮S1时均总压损失系数Y为10.32%,涡轮时均总总效率ηtt为82.26%;可转导叶的尾缘泄漏涡使第1级动叶（R1）流动产生强非定常性;可转导叶的尾缘泄漏涡和R1泄漏涡、壁面涡是造成第2级静叶（S2）流动非定常性的主要因素。     

变几何涡轮对涡轮气动性能的影响研究

针对自由涡轮导向器叶片可调的多级轴流涡轮进行气动性能研究。结果表明:通过改变自由涡轮导向器叶片角度可以调节多级涡轮的流量、效率、膨胀比分配和功率分配,自由涡轮导向器叶片角度变化对涡轮流场和各级静叶损失产生明显的影响。     

Numerical investigation of combustion characteristics for hydrogen mixed fuel in a can-type model of the gas turbine combustor

Numerical simulations are performed to analyze the combustion characteristics of propane fuel mixed with different amounts of hydrogen in a can-type combustor. The volume fraction of the hydrogen fuel varies from 0% to 100% in the fuel mixture. The results indicate that the hydrogen enrichment of the fuel significantly affects the flow structure, mixture fraction, and combustion characteristics. An increase in the volume fraction of hydrogen significantly affects the mean mixture fraction distribution, promotes combustion, and increases the flame temperature and the width of the flammable range within the combustor. Therefore, the degree of temperature uniformity at the outlet of the combustor increases with hydrogen enrichment, corresponding to an increase of 49.64% in the uniformity factor. The hydrogen enriched fuel can also reduce the emissions of CO and CO₂, owing to the reduced amount of carbonaceous fuel.     

Numerical simulation of the solar chimney power plant systems coupled with turbine

Numerical simulations have been carried out on the solar chimney power plant systems coupled with turbine. The whole system has been divided into three regions: the collector, the chimney and the turbine, and the mathematical models of heat transfer and flow have been set up for these regions. Using the Spanish prototype as a practical example, numerical simulation results for the prototype with a 3-blade turbine show that the maximum power output of the system is a little higher than 50 kW. Furthermore, the effect of the turbine rotational speed on the chimney outlet parameters has been analyzed which shows the validity of the numerical method advanced by the author. Thereafter, design and simulation of a MW-graded solar chimney power plant system with a 5-blade turbine have been presented, and the numerical simulation results show that the power output and turbine efficiency are 10 MW and 50%, respectively, which presents a reference to the design of large-scale solar chimney power plant systems.     

一种新的舰船燃气轮机状态监测系统

本文描述了一种新的舰船燃气轮机状态监测系统。该系统综合了先进的状态监测、性能分析、预测方法。利用专用模块进行在线或离线的燃气轮机性能监测／预测／诊断、传感器故障检测、故障及事件存储并提供维修措施。     

9E燃气轮机轻重油燃料切换控制程序的修改

分析了燃料系统主燃油泵出现的故障，指出严格控制轻重油切换过程中燃料油的温度变化率是非常重要的，并给出了该切换过程控制程序的修改方法。     

Numerical simulation of clocking effect on blade unsteady aerodynamic force in axial turbine

To give an insight into the clocking effect and its influence on the wake transportation and its interaction, the unsteady three-dimensional flow through a 1.5-stage axial low pressure turbine is simulated numerically by using a density-correction based, Reynolds-Averaged Navier-Stokes equations commercial CFD code. The 2nd stator clocking is applied over ten equal tangential positions. The results show that the harmonic blade number ratio is an important factor affecting the clocking effect. The clocking effect has very small influence on the turbine efficiency in this investigation. The difference between the maximum and minimum efficiency is about 0.1%. The maximum efficiency can be achieved when the 1st stator wake enters the 2nd stator passage near blade suction surface and its adjacent wake passes through the 2nd stator passage close to blade pressure surface. The minimum efficiency appears if the 1st stator wake impinges upon the leading edge of the 2nd stator and its adjacent wake of the 1st stator passes through the mid-channel in the 2nd stator. The wake convective transportation and the blade circulation variation due to its impingement on the subsequent blade are the main mechanism affecting the pressure variation in blade surface.     

Experimental and numerical studies of blade roughness and fouling on marine current turbine performance

The impact of blade roughness and biofouling on the performance of a two-bladed horizontal axis marine current turbine was investigated experimentally and numerically. A 0.8 m diameter rotor (1/25th scale) with a NACA 63-618 cross section was tested in a towing tank. The torque, thrust and rotational speed were measured in the range 5 < λ < 11 (λ = tip speed ratio). Three different cases were tested: clean blades, artificially fouled blades and roughened blades. The performance of the turbine was predicted using blade element momentum theory and validated using the experimental results. The lift and drag curves necessary for the numerical model were obtained by testing a 2D NACA 63-618 aerofoil in a wind tunnel under clean and roughened conditions. The numerical model predicts the trends that were observed in the experimental data for roughened blades. The artificially fouled blades did not adversely affect turbine performance, as the vast majority of the fouling sheared off. The remaining material improved the performance by delaying stall to higher angles of attack and allowing measurements at lower λ than were attainable using the clean blades. The turbine performance was adversely affected in the case of roughened blades, with the power coefficient (C_P) versus λ curve significantly offset below that for the clean case. The maximum C_P for this condition was 0.34, compared to 0.42 for the clean condition.     

Numerical investigation into influence of geometry on flow in a rotating cavity with an axial throughflow

For cooling design, in modern gas turbine engines, it is important to understand and predict the fluid flow and heat transfer in the high pressure compressor drum cavities, which have complex and varying geometries. Unsteady, three dimensional (3-D), Computational Fluid Dynamics (CFD) techniques are used to illustrate the great influence the geometry of these cavities has on flow and heat transfer. Comparisons are made with heat transfer measurements and general agreement is found. Predictions suggest that for certain geometries less computationally expensive axisymmetric CFD or boundary layer integral computations may be suitable for design purposes.     

Numerical investigations on the steady and unsteady leakage flow and heat transfer characteristics of rotor blade squealer tip

The steady and unsteady leakage flow and heat transfer characteristics of the rotor blade squealer tip were conducted by solving Reynolds-Averaged Navier-Stokes(RANS) equations with k-ω turbulence model.The first stage of GE-E3 engine with squealer tip in the rotor was adopted to perform this work.The tip clearance was set to be 1% of the rotor blade height and the groove depth was specified as 2% of the span.The results showed that there were two vortexes in the tip gap which determined the local heat transfer characteristics.In the steady flow field,the high heat transfer coefficient existed at several positions.In the unsteady case,the flow field in the squealer tip was mainly influenced by the upstream wake and the interaction of the blades potential fields.These unsteady effects induced the periodic variation of the leakage flow and the vortexes,which resulted in the fluctuation of the heat transfer coefficient.The largest fluctuation of the heat transfer coefficient on the surface of the groove bottom exceeded 16% of the averaged value on the surface of the squealer tip.     

Numerical investigation of the effects of rising angle on intermediate turbine duct and nearby turbines

In order to improve the efficiency,ultra-high bypass ratio engine attracts more and more attention because of its huge advantage,which has larger diameter low pressure turbine (LPT).This trend will lead to aggressive (high diffusion) intermediate turbine duct (ITD) design.It is necessary to guide the flow leaving high pressure turbine (HPT) to LPT at a larger diameter without any severe loss generating separation or flow disturbances.In this paper,eight ITDs with upstream swirl vanes and downstream LPT nozzle are investigated with the aid of numerical method.These models are modified from a unique ITD prototype,which comes from a real engine.Key parameters like area ratio,inlet height,and non-dimensional length of the ITDs are kept unchanged,while the rising angle (radial offset) is the only changed parameter which ranges from 8 degrees to 45 degrees.In this paper,the effects of rising angle (RA) on ITD,as well as nearby turbines,will be analyzed in detail.According to the investigation results,RA could be as large as 40 degrees in such model of this paper to escape separation;When RA increases,local inlet flow field of LPT nozzle appears to be with apparent variation;while a positive result is that outlet flow field could be kept almost unchanged through modifying blade profile.On the other hand,it seems optimistic that the overall total pressure loss could be kept nearly equivalent among different RA cases.And a valuable conclusion is that outer wall curvature is more important for pressure loss,which advises a clear direction for optimizing ITD.