文档介绍：基于层次径向基神经网络的汽轮机排汽焓计算
摘要
随着当前电力行业日新月异的快速发展,许多其他领域的高新技术不断的被应用到电力设计和改造的实际工程当中。本文仅就变工况时200MW汽轮机组的烟汽参数测算方法作一讨论。利用层次径向基神经网络的便捷运算功能,对汽轮机末级抽汽和排汽焓进行计算,该方法利用汽轮机设计数据和实际监测数据对排汽焓值进行估算,利用该方法有着计算精确度较高,收敛速度快等显著特点,很易适于实际工程应用当中。经对典型末级的某热电厂200MW汽轮机组末级抽汽及排汽焓值的计算,初步得出了汽轮机的排汽焓变化规律,为在线性能监测及排汽焓的分析测算提供了一种较为行之有效的方法。
关键词:排汽焓计算,层次径向基神经网络,200MW汽轮机,
The calculation of the exhaust enthalpy based on the theory of hierarchical radial basis work
Abstract
Along with the high and new technique of current electric power profession that the continuous changes and improvements's fast development, much the other realm is continuously of were apply toed the electric power design with the actual engineering that reform center. In this paper, a new method based on hierarchical radial basis work is presented, which discusses how to calculate the exhaust enthalpy of a steam turbine. It is based on the actual on-line monitoring datum and constructional datum of turbine to calculate the exhaust enthalpy. The result with which has a higher precision and the speed of converging is faster. It is suitable to the engineering application. Using this method to calculate a 200MW unit with a typical last stage, the variational rule of exhaust enthalpy is concluded. It is an effective method in analyzing and calculating the exhaust enthalpy in on-line performance monitoring.
Keywords: the calculation of exhaust enthalpy, hierarchical radial basis work ,200MW turbine
第1章引言
发电机组热力性指标对于汽轮机或电厂的设计、运行都非常重要。设计工况的指标是所有工况中最具有代表性的,因此设计工况下回热原则性热力系统计算最为普遍。而热电厂为确定其全年的热经济性,一般将选择全年中几个具有代表性的工况来进行计算,如冬季和夏季的平均工况等。
而实际运行状态下汽轮机运行工况是在改变的,通过汽轮机的蒸汽流量和蒸汽参数都将发生改变,汽轮机的某些级或全部级的反动度、级效率也随之发生变化。这样设计当中不可避免的要面对的矛盾就是设计工况的指标是否能够准确的反映生产中工况的变动问题,代表实际运行当中变动的工况。
再者,我们常用的指标η(汽轮机的汽缸效率)是缸内实际焓降Δh与理想焓降Δht之比即η=Δh/Δht 。各个缸的实际焓降Δh是可测参数(如温度、压力等)在焓-熵图上求得,但对汽轮机的低压缸焓降进行计算时,由于其排汽工质可能处于湿蒸汽区,需要温度、压力和干度三个参数才能确定排气焓,虽然现在可以应用一些热力软件在已知温度、压力、干度的情况下能查出,但排汽干度目前还难以实现在线检测,湿蒸汽排气焓无法通过常规方法得到,这样第二个困难就是热力系统热经济性在线分析仅通过人工方法难以实现。而且汽轮机组在线计算要求具有很高的实时性,为避免出现计算的滞后现象这就对整个计算周期有更