Saturator is one of the core components of humid air turbine (HAT) and is the main feature of HAT making it different from other gas turbine cycles. Due to the lack of sufficient experience in commercial plant operation, HAT cycle has a great demand for modeling and simulation of the system and its components, especially the saturator, to provide reference for system design and optimization. The conventional saturator models are usually based on the theory of heat and mass transfer, which need two accurate coefficients to ensure convincing results. This work proposes a global heat and mass transfer coefficient based on cooling tower technology to model the saturator in small-scale HAT cycle. Compared with the experimental data, the simulation results show that the proposed model well predicts the dynamic humidity and temperature distribution characteristics of saturator at low air pressure and temperature.

Due to the fact that the turbine outlet temperature of aeroderivative three-shaft gas turbine is low, the conventional combined cycle is not suitable for three-shaft gas turbines. However, the humid air turbine (HAT) cycle provides a new choice for aeroderivative gas turbine because the humidification process does not require high temperature. Existing HAT cycle plants are all based on single-shaft gas turbines due to their simple structures, therefore converting aeroderivative three-shaft gas turbine into HAT cycle still lacks sufficient research. This paper proposes a HAT cycle model on a basis of an aeroderivative three-shaft gas turbine. Detailed HAT cycle modelling of saturator, gas turbine and heat exchanger are carried out based on the modular modeling method. The models are verified by simulations on the aeroderivative three-shaft gas turbine. Simulation results show that the studied gas turbine with original size and characteristics could not reach the original turbine inlet temperature because of the introduction of water. However, the efficiency still increases by 0.16% when the HAT cycle runs at the designed power of the simple cycle. Furthermore, simulations considering turbine modifications show that the efficiency could be significantly improved. The results obtained in the paper can provide reference for design and analysis of HAT cycle based on multi-shaft gas turbine especially the aeroderivative gas turbine.

Three commonly used calculation methods of the thermal physical properties for gas turbine working medium are adopted.They are variable specific heat method(method A),the method based on the experimental data(method B),and the method based on the real gas state equation(method C).When the working medium is air or gas,the calculation errors compared with the public database query results of NIST chemical and physical property department is analyzed to get the most suitable calculation method for thermal physical properties of gas turbine.The results show that regardless of the low pressure or high pressure,w hen the temperature is more than 300 ℃,the calculation results of air of method B have a fixed deviation of 4 kJ/kg compared with the standard values,and the influ-ence of the fixed deviation will be reduced during the compression work,which proves that the accura-cy of method B;regardless of the working medium is air or gas,the error of the method A and C are larger,and method B is the most suitable method to describe the compression and expansion process of gas turbine.

采用建模仿真的方式对天然气供应系统的整体性能进行研究.首先基于模块化建模的理念设计了系统的各主要部件模型;随后根据燃机电厂的实际运行数据,通过BP神经网络训练得到天然气供应系统中的压力、值班/预混气流量设定规律;最后加入了基于比例-积分-微分控制原理的压力、温度和流量控制器,在Simulink仿真中完成了整体仿真模型的搭建.对所建模型进行了稳态和动态仿真,仿真结果与电厂实际数据基本一致,表明模型能够较为准确地反映天然气供应系统的整体性能.

The integrated gasification combined cycle (IGCC) is a power generation technology which combines clean coal technology with a combined cycle. The system modeling is significant for design, operation and maintenance of the IGCC power plant. However, the previous IGCC modeling methods only contained a simplified compartment gasifier model, which is useful to consider the heat transfer and chemical reaction inside the gasifier, but cannot analyze the pressure and flow distribution. In order to obtain a more accurate model of IGCC system, the volume-resistance technique and modular modeling method are utilized in this paper. The new model can depict the dynamic response and distribution characteristics of the gasifier, as well as their influence on the IGCC system. The simulation result of the gasifier and IGCC system shows an obvious delay after considering pressure and flow distribution. Therefore, the proposed IGCC system model can obtain a more reliable result when considering the distribution characteristics of the gasifier.

A simplified method is proposed to reduce the calculated quantity of two-phase lattice Boltzmann (LB) model for large density ratio. The simplified model not only apparently reduces the calculated quantity but also has a good stability for two-phase flow with large density ratio. Based on the simplified two-phase LB model, the impingement of droplet onto a stationary liquid film is simulated. The simulation of single droplet impacts onto liquid film is used to verify the applicability of the simplified model for the impingement process. It shows that the results calculated by the simplified model are in good agreement with experimental data in published paper. Then, the impingement process of double droplets with a horizontal distance and time interval onto a liquid film is simulated by two-phase lattice Boltzmann model. Different horizontal distances, droplet diameters, impact velocities, Reynolds numbers, relative film thicknesses and time intervals between the droplets are considered. The mechanism of the impingement process is analyzed. The rule of middle splash height is obtained. The changing rule of the middle splash height and the horizontal distance has a relationship with the droplet diameter. Larger Reynolds number makes height rise faster. Thicker liquid film leads a higher height but a slower rising rate. The time interval between the droplets would destroy the symmetry and make the flow become complex. It changes the middle splash direction and lowers the splash height. The flow mechanism of the impingement process is elaborated. (C) 2015 Elsevier Ltd. All rights reserved.

建立了燃气轮机性能仿真模型、叶片温度模型和叶片应力模型,以获取涡轮叶片的温度和应力.基于蠕变实验获取的Larson-Miller参数,建立了涡轮叶片蠕变损伤评估模型,将该模型分别应用于定时维护和视情维护体系下燃气轮机大修周期的规划.结果表明:压气机故障对蠕变寿命的影响大于涡轮故障;压气机损伤是对蠕变寿命影响最大的气路故障;该模型经校准后可指导实际维护活动.

应用累积偏差的概念,基于动态过程对燃气轮机在性能降级后的运行参数与正常状态下的运行参数进行比较,得到了部分性能降级与运行参数偏移之间的直观关系,并将累积偏差与稳态计算得到的降级参数进行对比.结果表明:基于动态过程的性能降级诊断方法相比稳态计算更为灵敏,动态过程中部分运行参数可以表征性能参数的降级,可用于诊断性能参数的降级情况.

基于两相格子Boltzmann模型,对大密度比下有一定水平间距的双液滴冲击液膜的流动过程进行了仿真,模拟了不同液滴初始间距和不同雷诺数下液滴冲击液膜的动态过程,重点分析了不同液滴初始间距和雷诺数下产生不同冲击和溅射现象的原因,以及不同参数对冲击和溅射行为的影响.总结了中心位置水花溅射高度随时间的变化规律,并论述了冲击和溅射过程中的内在作用机理.结果表明:在一定范围内,初始间距和雷诺数越大,中心位置水花溅射高度上升越快;随着雷诺数的增大,冲击、碰撞的程度越剧烈,中心位置水花顶端有液滴飞出.

Based on traditional simulation model of gas turbines,by comparing and analyzing the gas turbine performance between calculation results and experimental measurements,the effects of angle change of adjustable inlet guide vane(IGV)on the gas turbine performance were quantitatively obtained,and thus an improved simulation mode of heavy gas turbines was constructed considering the effects of IGV angle change on the gas turbine perfomrance.Results show that the steady state simulation results agree well with experimental data,exactly indicating the relationship between running parameters and the power of gas turbine,therefore the model may be used to the analysis of relevant dynamic characteristics and to the design of corresponding control systems of gas turbines.

IGCC system has been revealed to be a very attractive power generation system based on coal, promising highly efficient electricity generation and very low environmental impact. The integration of gasifier and power island will be a system engineering. This paper will investigate the influence of IGCC system configuration on system performance. Especially the exhaust heat utilization of syngas from gasifier will be discussed in detail. As the example, one E class gas turbine will be utilized as the core subsystem, the gasifier and HRSG system will be matched. A steady state thermodynamic model for IGCC system is developed on IPSEpro simulation platform and applied to a performance analysis. The characteristics under off-design and design condition for IGCC system were also analyzed.

Gasifier is one of core parts of Integrated Gasification Combined Cycle, which combines clean coal technology with combined cycle through the gasification of solid coal. The conventional lumped parameters simulation model cannot reflect the distribution characteristics in the gasifier.In order to obtain a more realistic model which can depict the dynamic response as well as the distribution characteristics, this paper utilizes the volume-resistance modeling technique and modular modeling method for the gasifier modeling. The gasifier will be divided into several compartments. The parameters in each compartment are uniform, while it has distribution characteristics for a whole gasifier. Thus the pressure and temperature distribution in the gasifier will be incorporated into the gasification process.The gasifier model in this paper can not only be used for the system performance analysis, but also for the control system design and debugging.

A two-phase Shan-Chen model with adjustable surface tension was proposed by improving the original lattice Boltzmann model,based on which falling film flow was simulated under 2-dimensional conditions respectively under Reynolds numbers of 5,10 and 20,so as to further study the flow characteristics of film with inlet disturbance,analyze the influence of external disturbance and surface tension on the steady-state wave motion,and to summarize the tendency of steady-state film development.Results show that the flow morphology acquired through numerical calculation is in good agreement with experimental data,demonstrating that the Shan-Chen model is capable of reflecting the physical process of falling film flow.

In order to study the reason of frequent pipe burst of heating surface in a 600 MW supercritical W-flame boiler, the numerical simulation of combustion process in boiler is carried out to study the impact of air distribution modes on pipe burst of boiler heating surface. The results show that the temperature field at furnace center is in W shape distribution and symmetric under actual operation conditions. The change of temperature field is not sensitive in the furnace when the ratios of primary air and inside secondary air are 5/6 and 6/5 in front and back arch, and the temperature flame doesn't sweep over the heating surface; however, when the ratios of outside secondary air in front and rear arch and the graded wind in front and back wall are 5/6 and 6/5, the furnace temperature field appears skew, and the temperature flame badly sweeps over the cold ash hopper, which may cause pipe burst of heating surface at cold ash hopper.

This paper presents an investigation on dynamic characteristics of a rod-fastened rotor. Based on the framework of a traditional Riccati transfer matrix method (TMM), an improved Riccati TMM considering contact effects brought by a face tooth is developed. A correction coefficient for equivalent stiffness imported from a three-dimensional (3D) finite element contact case analysis is defined to evaluate the contact effects, and then the dynamic model of the rod-fastened rotor including bearing support is established. A computer program is further developed to obtain the dynamic characteristics such as critical speeds of lateral vibration, mode shapes, and an unbalance response. The improved TMM is applied to investigate the dynamic characteristics of a real central tie rod rotor of the class-F gas turbine for verification of its effectiveness, and the calculated critical speeds are in good agreement with test measurement results, implying that the method is accurate and the dynamic model is reliable. This approach can also be applied to analyze other combined rotors with a homogeneous structure.

The pursuit of increased efficiency and economy by the trucking industry has led to the increasing use of wide-base tyres that are subjected to higher inflation pressure and heavier truck loadings. In evaluating the structural adequacy of pavements to sustain the applied wheel loads, this paper presents a finite element method to estimate the deflection and contact characteristics of a wide-base tyre on a rigid pavement under static load, focusing on nonlinear material, geometric and contact problems. The computed model is qualitatively compared with the experimental data to examine its validity. It is concluded that both inflation pressure and static load play an important role in the tyre pavement interaction process. Analysis results provide reliable predictions for vertical inflation, contact patch area and stress distribution of the wide-base tyre under different inflation pressures and loads and a better approximation of the effects of non-uniform tyre contact stresses on rigid pavement response variables is achieved.

Rod fastening rotor is usually used in heavy duty gas turbine rotor-support system,of which critical speed calculation differs from that of the integral rotor.In the framework of Riccati transfer matrix method,discretization of central tie-rod fastening rotor structure with detailed analysis was conducted.Taking into account the impacts which are brought by bearing support and meshing face tooth on dynamic characteristics of rotor system,a computation model of rotor-support system was further established.In this way,critical speeds and the corresponding modes were obtained.The calculated result shows a good agreement with the test measurement result,which implies that the method is accurate and computation model is reliable.This approach can also be applied to analyze dynamic characteristics of rotors with homogenous structure.

During the lifetime of a gas turbine, its gas path components deteriorate gradually and sometimes serious problems happened. Direct physical and indirect model based methods can be used in health monitoring systems for gas turbines. The gas turbine under study is run as part of a combined cycle generation unit, sited in the BAO Steel Power Plant. The basic health monitoring system is based on vibration signal. After the vibration monitoring system failed to detect foreign object damage (FOD) fault, a health monitoring system based thermodynamic model is tried to explain quantitatively why the performance degradation happened, with the foreseeable usage as part of the online health monitoring system. The present work is based upon component level nonlinear gas turbine model, so errors caused by linearization can be avoided. The component level model of gas turbine is built as dynamic model, and the off-design performance of gas turbine is evaluated as the steady-state solution of the dynamic model. A dynamic tracking filter, which tracking field measurements with PI control loops, is incorporated into the gas turbine dynamic model. Output of the dynamic tracking filter is called correction factors, which are used as multiplicative corrective values of component performance parameters (i.e., flow or efficiency) in the gas turbine model. With dynamic tracking filter and aero-thermal dynamic model, the model based fault diagnosing of gas turbine is implemented as a three step process. As a case study, several measurement data sets are tried to detect and isolate FOD fault happened. The result demonstrates that a model based gas path analysis can detect and isolate fault even when no vibration level alarm is reported.

Heat exchangers and pre-reformers are critical devices for high temperature fuel cell systems. It is recommended to incorporate a compact heat exchange and the pre-reformer when considering the limited space and cost. The volume-resistance characteristic modeling technique is introduced here to meet the requirement for quick dynamic and real time simulations. The distribution characteristics along the heat exchange reformer length direction are presented, and some key effect factors are studied. The transient behaviors are investigated for different step-change conditions, such as mass flow rate and inlet temperature. This can provide some references and tools for the fuel cell system design and optimization.

Based on the features of thermodynamic system for the 350 MW unit in one power plant,the emulation model for said system has been established.Results of emulation under condition of mixedly burning coal and blast furnace gas of low calorific value show that the main parameters tally with the actual parameters in operation of unit.On the basis of this,directing against the problems of high discharged flue gas temperature etc.existing in mixedly burning,analysis has been carried out,and improvement measure of suitably increasing the heat exchange area of air preheater has been put forward,so as to reduce the discharged flue gas temperature and enhance the boiler effciency.