基于流型判别准则的排汽焓的准确在线监测方法

An Accurate On-line Monitoring Method of the Exhaust Steam Dryness Based on Discriminant Criteria of the Flow Patterns

随着信息计算机技术发展,对大型汽轮发电机组进行性能在线监测及分析成为可能。机组能耗率和干度是两个被监测的重要指标。通过对已往的汽轮机变工况计算方法分析,提出以汽轮机末级抽汽或次末级抽汽(过热蒸汽状态)为计算起点的汽轮机的顺序变工况核算方法。根据初始假定的末级流量和现场实际的末级前热力状态和背压,用汽轮机变工况流型判别准则,判别级的流型,然后从末级前参数开始顺序进行一次级的变工况核算,得到新的排汽焓和排汽干度,最后算得机组的能耗率和排汽焓(或排汽干度)。这样既不用流量测量,也不用排汽干度测量,就能准确地在线监测机组能耗率和排汽干度。

With the development of information and computer technology, it is possible to monitor and analyze on-line features of large steam turbine-generator units. The energy consumption rate and the exhaust steam dryness are two important indices. Base on the analyses of those existed calculation methods for turbine varying condition, we give a sequential varying condition calculation that starts with steam extraction of the final stage or the second final stage （superheated steam condition）. According to the initially assumed final stage flow, and the thermodynamic parameters before the final stage, also the baekpressure, we can distinguish the flow patterns of the stage by a diseriminant criteria. Then we can conduct a stage varying condition calculation of primary stage in sequence from the front final stage parameter, so the new exhaust steam enthalpy and the exhaust steam dryness can be got. So the precise energy consumption rate and the exhaust enthalpy （or the dryness） can be got easily. Obviously, without measuring the flow or the dryness, we can accurately monitor the on-line energy consumption rate and the dryness of the units.