汽轮机变工况模型的简便建立方法及应用

A simple method to construct variable condition model for steam turbine and its application

鉴于汽轮机详细变工况计算方法在实际计算过程中很难开展,本文提出了一种根据机组热平衡图构造变工况计算模型的简便方法,并采用该方法建立了汽轮机定流量和定功率变工况计算模型。以某超临界660 MW机组为例,运用所建立的定功率变工况模型计算得到机组典型工况下的各参数值,计算结果与设计值相比误差较小;运用所建立的定流量变工况模型计算得到了四阀全开工况下主蒸汽压力、主蒸汽温度、再热蒸汽温度、再热压损和排汽压力变化对热耗率和功率的修正曲线,与制造厂提供的修正曲线相比误差较小。这表明所建立的变工况计算模型精度较高,满足工程计算的要求。

Since the detailed variable condition calculating method of steam turbine is very difficult to be used in the actual calculation process, a simple method to construct variable condition model according to heat balance diagram of the unit was proposed. By employing this method, calculation model of constant flow and constant power variable condition for steam turbines were developed. Moreover, by taking a supercritical 660 MW unit as an example, this model was applied to calculate the values of typical parameters under different typical conditions,and comparison between the calculated values and designed valves indicates the deviation was small. Furthermore,the correcting curves of main steam pressure, main steam temperature, reheat steam temperature, reheater pressure drop and exhaust steam pressure on heat rate and power under VWO condition were also obtained. The difference between the calculated correcting curves and that provided by the manufacturer was small. It demonstrates that the accuracy of the above variable condition model is high and can meet requirements of engineering calculations.