蒸发系统分布参数特性动态仿真研究

为了全面的把握蒸发系统的动态特性,应用基于炉内三维燃烧检测的蒸发系统分布参数模型对某台300MW锅炉进行了仿真研究。讨论了求解模型的数值算法,以提高仿真速度。以电厂实测数据作为分布参数模型的输入,获得壁面平均热流、汽包压力和汽包出口蒸汽流量动态特性;以扰动激励的方式,获得水位动态特性。将模拟计算结果与实测值／文献模型的模拟值或者文献仿真结果进行比较,证明了模型的有效性。仿真计算了壁面热流、壁面温度、质量含汽率以及质量流速等热力参数在蒸发受热面上的动态分布,结果表明各热力参数在水冷壁上呈现明显的分布参数特性,并且其分布特性随着工况的变化而变化。模型即可用于在线预测也可用于离线分析计算,为锅炉安全性与可靠性评价提供重要依据。

Dynamic Simulation of Distributed-parameter Characteristics of Evaporation System

To grasp the dynamics of evaporation system of boiler in detail, a simulation is made on a 300MW power plant boiler using the distributal parameter model based on three-dimensional combustion monitoring in furnace. The solution algorithm for the model is proposed to enhance the simulation speed. Taking the measured data of the power plant as the inputs of the model, average wall heat flux, drum pressure and steam mass flow rate in the outlet of the system are calculated; by the drives of some typical perturbations, dynamics of drum level is obtained. Simulation results are compared with those of plant data/other model or references, which shows that the model is effective to represent the dynamic process of evaporation on system. Dynamic distributions of some important thermodynamic parameters on evaporating heat surface, consisting of wall heat flux, wall temperature, mass fraction of steam and mass velocity, are also calculated, and the results are analyzed. Analyzed results indicate that the characteristics of these parameters are remarkably distributed and will change as the operation condition changes. The model can be applied for online prediction or off-line calculation, which provides an important basis to evaluate the security and reliability of power plant boiler.