间接空冷系统变工况快速计算模型

Fast calculation model of indirect air-cooled system under off-design condition

以某600 MW机组大型间接空冷系统为对象,分别建立了凝汽器热力计算模型与空冷塔数值计算模型,按照正交实验方法设计了49组工况,通过耦合迭代的方法对机组变工况运行进行了数值模拟,得到了相应的变工况运行特性信息.以所得数值模拟结果为样本,基于最小二乘支持向量机,建立了反映机组变工况运行特性的背压快速计算模型,在机组运行的全工况范围内反映了环境温度、侧风风速和热负荷变化对机组背压的影响.该方法结合了数值模拟方法机理建模的准确性和最小二乘支持向量机良好的泛化能力,计算高效,可为机组经济与安全运行提供连续定量的指导.

Taking a 600 MW indirect air-cooled unit as an example, thermal calculation model of the condenser and numerical calculation model of air-cooled tower are established, respectively. In order to obtain operating characteristics of the indirect air-cooled system under off-design condition, 49 nu- merical simulations were carded out with the coupled method according to orthogonal experimental design. Based on least square support vector machine, a fast calculation model for back pressure which reflects operating characteristics of the unit is established based on the results of numerical computation. By this model, the effects of ambient temperature, crosswind speed and thermal load on back pressure of the unit are obtained under all working conditions. Combining the accuracy of numerical simulation based on mechanism and excellent generalization of least square support vector machine, this model has fast calculation speed and provides a continuous and quantitative guidance for the economic and safe operation of the unit.