汽轮机当量汽态线及其变化对经济性的影响

Turbine Equivalent Condition Curve and Its Effect on Economy

采用指示性相对内效率的定义,提出当量汽态线的概念,并据此推导出相应的汽轮机热耗计算模型。该模型不需要各缸抽汽温度的测量值,不仅简化了热耗计算,降低了测量要求,而且使当量汽态线和缸效率有了一致的对应关系。通过对依据两种汽态线建立的热耗率计算模型进行误差比较,可以看出二者误差非常小,所以使用当量汽态线后简化的热耗率计算模型可以用于汽轮机经济指标的计算与诊断。在汽轮机变工况模型的支持下,研究了汽轮机缸效率变化对热耗率的影响。数值试验结果表明:使用当量汽态线的概念不仅可以简化热耗率计算模型,而且便于评价汽轮机各缸相对内效率变化对机组经济性的影响。

Adopting the definition of indicated relative internal efficiency, the concept of equivalent condition curve was proposed and corresponding turbine heat rate model was derived. This model doesn't need the measured value of in-between extraction temperature, which not only simplifies the calculation of heat rate and reduces the requirement of measurement but also brings corresponding relation between condition curve and cylinder efficiency. Through the error comparison between heat rate models based on the two kinds of condition curve, result shows the error is very small. So the simplified heat rate model based on equivalent condition curve can be used in the calculation of economic index and diagnosis of turbine. Supported by turbine off-design performance model, the effect of cylinder efficiency on heat rate is studied. Result of numerical experiment shows that the concept of equivalent condition curve is convenient for evaluating the effect of cylinder efficiency on turbine economy as well as simplify the heat rate model.