背压微增条件下汽轮机出力的简化计算

Simplified Calculation of the Output Power of a Steam Turbine Under the Condition of the Back Pressure Being Slightly Increased

为获得准确的背压微增条件下汽轮机出力特性，分析背压变化时机组热力系统变工况实际运行特性，基于对热力系统的合理假设和相关经验公式的应用，在忽略汽轮机本体结构和内部级组热力参数变化的前提下，提出了汽轮机背压微增出力特性的简化计算方法。以某300MW湿冷机组和660MW间冷机组的变背压工况性能试验数据为例进行验证，结果表明，简化计算获得的微增出力特性曲线的斜率和试验结果偏差在3％以内，是一种行之有效的背压微增出力特性高精度计算方法。

To acquire the accurate output power characteristics of a steam turbine under the condition of its back pressure being slightly increased, through analyzing the actual operation characteristics of the thermal system of the unit under the off-design conditions when the back pressure varies, on the basis of the rational assumptions and the corresponding empirical formula of the thermal system under the precondition of the structure of the proper of the steam turbine and any changes in the thermodynamic parameters of the groups of its internal stages being neglected, proposed was a simplified method for calculating the output power characteristics of the steam turbine under the condition of the back pressure being slightly increased. A verification was conducted by using the test data of the performance of a 300 MW wet-method cooling unit and a 660 MW intercooling unit under the condition of the back pressure being varied. It has been found that the deviation between the slope of the output power characteristic curve obtained during the simplified calculation under the condition of the back pressure being slightly increased and the test data is within a range of 3% ,thus the simplified calculation method is an effective high precision one for calculating the output power characteristics when the back pressure had been slightly increased.