浅析燃气轮机的可靠性及应用

随着燃气轮机的广泛运用,提高燃气轮机可靠性已经成为十分关注的问题。根据燃气轮机的基本工作原理,对其可靠性的影响因素进行了简单的分析,并就提高其可靠性措施做了简单描述。     

某重型燃气轮机燃烧室燃烧流动的数值模拟

对某重型燃气轮机燃烧室燃烧天然气进行数值模拟,在模拟过程中采用了雷诺应力模型、EBU-Arrheniue湍流燃烧模型和六通量辐射模型来描述其燃烧流动过程,运用FLUENT软件求解了三维流场和温场分布.计算结果能够很好地反映该重型燃气轮机燃烧室燃烧流动特点,对预测燃烧室内的燃烧流动有一定参考价值.     

Friction and Wear Characteristics Due to Stick-Slip under Fretting Conditions

Friction and wear characteristics between two steel surfaces under fretting conditions are investigated experimentally. The fretting damage caused by low-amplitude oscillatory sliding can be classified into three regimes of gross-slip, mixed-slip, and partial-slip due to the stick-slip phenomenon. One of the most important characteristics of fretting wear is the transition from gross-slip to mixed-slip. Several criteria have been introduced for a quantitative determination of the transition between mixed-slip and gross-slip. However, the transition criteria have some problems in determining the regimes because parameters are difficult to calculate or depend on the system. To introduce new transition criteria in this study, the phase difference between friction force and relative displacement is used to determine the transition and predict the fretting wear. It is found that the phase difference with a range of 0° to 90° can predict the onset of fretting conditions.     

Wear analysis of materials used as orthopaedic implants

In the biomedical field, about 6% of the hip total prostheses must be replaced after 9 years. One of the main causes of the aseptic loosening may be attributed to fretting corrosion between the prosthesis and the bone cement. To understand this degradation, a fretting test between a stainless steel, 316L and PMMA has been used in Ringer solution. Fretting maps for the contact 316L/PMMA were determined in air and in Ringer solution. It has been shown that the lubricant effect of the aqueous environment shifts the gross slip/partial slip transition towards larger normal forces or lower displacements.To understand the fretting degradation behaviour of 316L against PMMA, fretting corrosion experiments have been investigated under constant applied potential. The first conclusion is that the dissipated energy is maximum at about −600 mV/SCE. The wear on PMMA does not depend on the applied potential. Moreover, the wear coefficient is lower than that in air due to the lubricant effect of the Ringer solution. Wear on 316L depends on the applied potential. The wear volume is minimum at −600 mV/SCE although the dissipated energy is maximum. The wear on 316L in Ringer solution is attributed to a dissolution process due to the local destruction of the passive film by fretting. The effect of potential on the wear of 316L may be accounted for by changes in the aqueous environment confined in the contact zone due to a restricted mass transport from the bulk solution and to the large local current densities consecutive to the destruction of the passive film. Accordingly, the wear volume on 316L is correlated to the time. Finally, the proton reduction, inside the contact, is believed to contribute significantly to the dissolution process.     

大气参数对燃气轮机进气冷却效果的影响

针对燃气轮机进气冷却的效果在不同大气参数下变化很大的问题,对燃气轮机进气冷却装置的热力过程、影响因素、经济效果等方面进行了研究。基于某电厂燃气轮机和燃气-蒸汽联合循环机组的运行数据,利用热平衡仿真软件Gate Cycle对两种发电机组系统进行模块化建模,并增加进气冷却装置,定量分析了两种发电机组进气被冷却后输出功率的增加量(即进气冷却效果)在不同大气参数(温度、相对湿度和压力)下的变化情况。研究结果表明,大气参数的变化,会对燃气轮机进气冷却的效果产生很大影响,两者之间呈现出一定的数值关系。     

燃气轮机动态仿真容积效应法研究

针对燃气轮机动态建模容积效应法运用过程中,使用真实体积运算时计算结果振荡较大,无法对燃气轮机动态过程进行实时有效的运算的问题,对容积效应法的原理进行分析,提出了采用虚拟容积计算方法计算容积大小.采用面对对象的模块化建模方法,基于Matlab/Simulink平台,运用容积效应法建立了燃气轮机动态仿真模型,解决了在常规建模时迭代次数太多的问题.分别计算了在相同工况变化条件下,采用真实容积和虚拟容积方法建立的两种模型的仿真结果.研究结果表明,采用虚拟容积的仿真模型更稳定,并且计算结果更准确.     

Evaluation of component characteristics of a reheat cycle gas turbine using measured performance data

In this work, component characteristics of a reheat cycle gas turbine in a commercial combined cycle power plant were evaluated. An inverse performance analysis, in which component characteristic parameters were estimated based on measured performance data, was carried out. The measured parameters were the power, the fuel flow rates of two combustors, and the temperatures and pressures at various locations such as the compressor discharge, exits of both the high-and low-pressure turbines. The estimated parameters from the analysis include the compressor and turbine efficiencies and the inlet air flow rate. The analysis was performed for a wide operation range in terms of the ambient temperature and load, providing a database for the variations of the characteristic parameters with changes in the operating condition. In addition, a sensitivity analysis was performed to examine the influence of the uncertainties of the measured parameters on the estimated parameters. The analysis program can be further developed into a performance diagnosis tool and the obtained component characteristic data can be used as reference database.     

Ignition and combustion characteristics of the gas turbine slinger combustor

This paper describes the ignition and combustion characteristics of a gas turbine slinger combustor with rotating fuel injection system. An ignition test was performed under various airflow, temperature and pressure conditions with fuel nozzle rotational speed. From the test, there are two major factors influencing the ignition limits: the rotational speed of the fuel nozzle, and the mass flow parameter. Better ignition capability could be attained through increasing the rotational speed and air mass flow. From the spray visualization and drop size measurement, it was verified that there is a strong correlation between ignition performance and drop size distribution. Also, we performed a combustion test to determine the effects of rotational speed by measuring gas temperature and emission. The combustion efficiency was smoothly enhanced from 99% to 99.6% with increasing rotational speed. The measured pattern factor was 15% and profile factor was 3%.     

气体涡轮流量计结构优化研究

以TM80气体涡轮流量计为研究对象,采用数值模拟与实验测试相结合的方法对其进行结构优化研究。数值结果表明压力梯度骤变和边界层分离的出现主要由流量计的表芯支座和后导流体引起。由此提出了关于表芯支座坡度和后导流体直径的结构优化方法,将表芯支座的坡度设计为15°,将表芯支座侧面的台阶流转变成渐缩流;将后导流体直径缩减为62 mm,将后导流体侧面的台阶流转变成等直径的管道流。数值模拟和实验测试证实,当表芯支座坡度设计为15°、后导流体直径设计为62 mm时,流量计的压力损失显著降低,仪表系数变得更加稳定,线性度误差明显变小,说明该结构优化方法可以明显提升流量计的计量性能。研究结论有助于为今后开发性能更好的气体涡轮流量计提供有力的理论指导和技术支持。     

Analysis of the combustion instability of a model gas turbine combustor by the transfer matrix method

Combustion instability is a major issue in design of gas turbine combustors for efficient operation with low emissions. A transfer matrix-based approach is developed in this work for the stability analysis of gas turbine combustors. By viewing the combustor cavity as a one-dimensional acoustic system with a side branch, the heat source located inside the cavity can be described as the input to the system. The combustion process is modeled as a closed-loop feedback system, which enables utilization of well-established classic control theories for the stability analysis. Due to the inherent advantage of the transfer matrix method and control system representation, modeling and analysis of the system becomes a straightforward task even for a combustor of the complex geometry. The approach is applied to the stability analysis of a simple combustion system to demonstrate its validity and effectiveness. This paper was recommended for publication in revised form by Associate Editor Ohchae Kwon Dong Jin Cha received his B.S. and M.S. degrees from Hanyang University in Seoul, Korea, in 1981 and 1983, respectively. He then received his Ph.D. in ME from the University of Illinois at Chicago in 1992, and worked at the US DOE NETL for the next three years as a National Research Council (NRC) Associate. Dr. Cha is currently a Professor at the Department of Building Services Engineering at Hanbat National University in Daejeon, Korea. His research interests include combustion instability of gas turbine for power generation and fluid flows in building services engineering. Jay H. Kim received his BSME from Seoul National University in 1977, MSME from KAIST in 1979 and Ph.D. in ME from Purdue University in 1988. He has joined the Mechanical Engineering faculty of the University of Cincinnati in 1990, and is currently a Professor. Before joining the University of Cincinnati, he worked in industry for six years in Korea and US. His research interests have been in broad areas of acoustics, vibrations and applied mechanics with recent focuses on human/bioacoustics and vibration, gas pulsations and elastic stability. Yong-Jin Joo received his BSME and MSME from Sung Kyun Kwan University in Seoul, Korea, in 1990 and 1992, respectively. Mr. Joo is currently a Project Leader for IGCC Operation Technologies at KEPRI (Korea Electric Power Research Institute) which is the central R&D center of KEPCO (Korea Electric Power Corporation). His research interests include the development of operation and maintenance simulator for power plants including IGCC.     

汽轮机旁路系统与阀门选用

介绍了我国典型的内汽轮机旁路系统结构,分析了汽轮机旁路系统中阀门的安装、调试及故障排除。     

LDA-measurements in natural gas high-pressure pipelines for the testing of turbine gas meters

In industrial gas volume measurement, the reliable, precise and economically efficient determination of gas quantities by measurement is of utmost importance. Standby meter sections, Z-connection and permanent series connection of two gas meters of different designs are state of the art [Schmittner, D., The importance of the accuracy of measurement for industrial gas measurements. 3R International, Vol. 30, No. 6–7, 1991, pp. 338–343 (in German)]. The permanent or temporary series connection for the comparison and test section makes expenses for a second complete measuring device necessary. An alternative at present is the dismounting of the gas meter and the check test in an appropriate high-pressure test facility. A test according to requirements, using a non-interacting measuring instrument which should be transportable, if possible, and usable with other gas meters can be a bridge between these two possibilities. To prove this, measurements with an LDA system were carried out in a natural gas high-pressure pipeline upstream of a turbine gas meter. After extensive profile and single-point measurements have been made it can be said that this test by the single-point method is feasible with an uncertainty of ≤ ± 0.5%, providing defined prerequisites are met.     

Combustion instability mechanism of a lean premixed gas turbine combustor

Lean premixed combustion has been considered as one of the promising solutions for the reduction of NOx emissions from gas turbines. However, unstable combustion of lean premixed flow becomes a real challenge on the way to design a reliable, highly efficient dry low NOx gas turbine combustor. Contrary to a conventional diffusion type combustion system, characteristics of premixed combustion significantly depend on a premixing degree of combusting flow. Combustion behavior in terms of stability has been studied in a model gas turbine combustor burning natural gas and air. Incompleteness of premixing is identified as significant perturbation source for inducing unstable combustion. Application of a simple convection time lag theory can only predict instability modes but cannot determine whether instability occurs or not. Low frequency perturbations are observed at the onset of instability and believed to initiate the coupling between heat release rate and pressure fluctuations.     

轴针式喷嘴内部空化与针阀密封面磨损特性

喷嘴是柴油机的核心部件之一,其空化与磨损特性对柴油机的雾化、燃烧与动力特性均存在重要影响.从可视化和数值模拟两个方面研究柴油机轴针式喷嘴内部燃油的流动状况.结果表明,针阀开启前燃油就存在大量空泡,开启后针阀密封面上游处的空化现象较下游严重.在S195柴油机上,利用扫描电镜(Scanning electric microscope,SEM)研究轴针式喷嘴针阀密封面的磨损特性.结果表明,密封面上上游处的原始凹坑缺陷在运转20 h后出现较明显的磨损,而下游处的原始凹坑缺陷没有明显的磨损,即实际磨损严重的部位与空化密度大的部位一致.上游凹坑缺陷处磨损严重的原因是,原始的凹坑缺陷是空化的发生源,原始的凹坑缺陷处倾向于汇聚空泡,团聚的空泡溃灭,对壁面产生磨损.研究结果为减缓轴针式喷嘴针阀密封面的磨损提供理论依据.     

基于PLC的燃气轮机进气冷却测控系统的研制

介绍了由PLC作为下位机的燃气轮机进气冷却测控系统,详细阐述了测控系统的设计方案以及PLC的功能实现.运行结果表明,该系统性能稳定可靠,自动化程度高,能够满足进气冷却的测控要求.     

YL-14000A型烟机转子振动处理

详细介绍炼油厂催化车间烟气轮机YL-14000A转子振动故障分析及处理过程,消除振动前后烟机回收能量的对比,为烟机更好运行提供有益的思路。     

M701F燃气轮机温度控制回路分析

燃机透平进口温度是影响燃机热效率的重要参数,温控的最终目的是控制透平的工作温度。本文针对M701F燃机温度控制方式和工作状况进行分析,阐述了IGV和燃烧室旁路阀开度变化对温度的影响,并介绍了惠州LNG电厂BPT变化趋势大导致自动停机的处理情况。可对同类9F级燃气-蒸汽联合循环机组的运行维护提供参考和借鉴。     

三菱M701F型燃气轮机控制系统分析

Mitsubishi公司的M701F型燃气轮机是从国外引进的大型燃气轮机机组;其控制系统采用Mitsubishi公司自身开发的Diasys Netmation,该文主要分析M701F型燃气轮机的控制系统,特别对燃气轮机的温度控制系统进行了详细分析.     

分析内燃机的磨损磨粒-利用铁谱加热法

阐述了内燃机摩擦磨损机理和铁谱技术。通过利用铁谱加热分析法对内燃机的摩擦磨损进行分析与研究。这一分析方法对于分析和鉴别多摩擦副工况下的油液中各类磨粒的材质成分是一种极为有效方法,并且为内燃机摩擦磨损的故障诊断提供了有利的科学依据。     

Torsional Fretting Wear Behavior of Bonded MoS2 Solid Lubricant Coatings

The effects of applying a bonded MoS₂ solid lubricant to a 1050 steel substrate were investigated using a torsional fretting wear apparatus. Tests were conducted under a normal load of 50 N with angular displacement amplitudes ranging from 0.1 to 5°. Wear scars were examined using scanning electron microscopy, energy-dispersive X-ray spectrometry, optical microscopy, and surface profilometry. The MoS₂ coating exhibited different torsional fretting regimes than those of the substrate. Fretting regimes of the coating were primarily in the partial slip regime (PSR) and the slip regime (SR) with no mixed fretting regime. The width of the PSR narrowed. Due to the lubricating effects of the coating, the friction torque was consistently lower than that of the substrate. The damage to the coating in the PSR was very slight, and its granular structure remained even after 1,000 cycles. The damage mechanism to the SR coating was a combination of abrasive wear, oxidative wear, and delamination. The MoS₂ coating had potential to alleviate torsional fretting wear.