大型燃煤发电机组汽轮机系统仿真建模与变工况特性研究

发布时间：2018-04-05 00:08

本文选题：汽轮机系统　切入点：变工况　出处：《华中科技大学》2014年硕士论文

【摘要】：当前全国能源结构以火电为核心，研究电站系统的运行特性和能耗分布是一项重要的任务，汽轮机系统作为火电站的核心设备，研究其工作特性和经济性是研究电站热力系统的首要任务。而在系统运行过程中，设备状态的变化是不可避免的，故此时运行工况会偏离设计工况，而整个系统的变工况特性不能用传统的方法来评价。使用仿真建模技术，建立汽轮机系统全工况仿真模型，并利用该模型研究汽轮机系统的变工况工作特性，这是本论文研究任务的根本出发点。论文研究和阐述了汽轮机变工况计算的相关方法和理论，重点研究了汽轮机变工况近似计算中被广泛使用的弗留格尔公式方法，指出了其误差过大且无法满足部分故障工况计算的缺点，说明了该计算方法不适用于本课题模型建立的原因，并考证了“弗留格尔公式”这一名词的出处。针对某600MW超临界机组，分析其汽轮机系统的组成和工作特性，，以及其变工况运行的特点，按照分段模块化建模的思想，建立其汽轮机系统各部分模型。在排除使用经典弗留格尔公式的前提下，根据设计数据，分析级组前后压比和带有马赫数M a和绝热系数k的函数间存在简单函数关系，并利用该关系，建立了新的汽轮机本体仿真模型，并对该模型进行了计算验证；利用分段建模的思路，将汽轮机旁路系统分为节流减压段和喷水减温段，根据各段的工作原理建立了汽轮机旁路系统仿真模型。利用全部已建立的模型，将之结合成为汽轮机系统总体模型，并进行变工况计算研究。计算了包括机组负荷变化，主再热蒸汽单参数变化，主蒸汽压力温度耦合变工况，回热加热器换热系数变化，回热加热器切除，回热加热器端差变化以及再热事故喷水等机组变工况运行特性，以热耗率作为主要研究对象，整理并分析了以上各个变动工况下系统热耗率的变化值和变化趋势，指出了这些工况变动对汽轮机能耗的影响，并将其与设计值进行了对比研究，验证了模型在变工况条件下计算结果的正确性。
[Abstract]:At present, thermal power is the core of the national energy structure. It is an important task to study the operating characteristics and energy consumption distribution of the power plant system. The steam turbine system is the core equipment of the thermal power plant.It is the most important task to study the thermodynamic system of power station by studying its working characteristics and economy.During the operation of the system, the change of the equipment state is inevitable, so the operating condition will deviate from the design condition, and the off-condition characteristic of the whole system can not be evaluated by the traditional method.Using the simulation modeling technology to establish the simulation model of steam turbine system under all working conditions, and using the model to study the working characteristics of the steam turbine system under different working conditions is the basic starting point of the research task in this paper.In this paper, the relevant methods and theories of variable working condition calculation of steam turbine are studied, and the Flieger formula method, which is widely used in approximate calculation of steam turbine variable working condition, is emphatically studied.This paper points out the shortcoming that the error is too large and can not satisfy the calculation of partial fault condition, explains the reason why the calculation method is not suitable for the model establishment of this subject, and verifies the origin of the term "Fligel's formula".In view of a 600MW supercritical unit, the composition and working characteristics of its steam turbine system and the characteristics of its operation under different working conditions are analyzed. According to the idea of piecewise modular modeling, the models of each part of the steam turbine system are established.On the premise of excluding the use of the classical Flieger formula, and according to the design data, it is analyzed that there is a simple functional relationship between the pre-and post-stage pressure ratio and the functions with Mach number Ma and adiabatic coefficient k, and the relationship is used.A new simulation model of steam turbine body is established, and the model is calculated and verified, and the steam turbine bypass system is divided into throttling decompression section and water injection reducing temperature section by using the idea of subsection modeling.According to the working principle of each section, the simulation model of steam turbine bypass system is established.Using all the established models, the whole model of steam turbine system is combined, and the off-condition calculation is carried out.The calculation includes unit load change, main reheat steam single parameter change, main steam pressure temperature coupling variable working condition, heat transfer coefficient change of regenerative heater, recuperative heater excision,The variation of the end difference of the regenerator and the operating characteristics of the units such as reheat accident water injection etc. Taking the heat consumption rate as the main research object, the variation value and trend of the heat consumption rate of the system under each of the above changing conditions are sorted out and analyzed.The effect of these variations on turbine energy consumption is pointed out and compared with the design value, which verifies the correctness of the model under the condition of variable working conditions.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621

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