Dynamic Mathematical Model Of Distributed Parameter For Steam-Water System Of Supercritical Pressure Boiler

In order to adapt the demand of modulation peak to develop once—through boiler, its dynamic characteristic under various working conditions and sensitivity to all kinds of disturbances will directly influence various load ability and safe economy function of boiler. The study of supercritical pressure once—through boiler in home are in an initial stage at the present. accordingly, it is critical effect to grip the dynamic characteristic of unit which establish the dynamic mathematical model of supercritical fossil power unit and do research analysis on simulation. In this paper, taking one 1900t/h supercritical pressure once—through boiler installed in East boiler company as subject investigated, analyzing the structure and characteristic of unit, from the mechanism of units, based on the law of quality conservation, energy conservation and momentum conservation, having Lagrange fluid particle tracing idea in hydrodynamics field application in analyzing of unit operational characteristic, author build up the nonlinear distributed parameter general dynamic mathematical model of single-phase heating surface or diphase heating surface in the steam-water system for supercritical pressure once—through boiler, which is suitable numerical calculation and simulation for large scale disturbance and full working conditions change, and enough materializing distributed characteristic of thermodynamic parameter in process and time lag characteristic of energy transportation in tache. The transient responses curve of the system main variables under several disturbance are computed by Computer Simulation for the model, and theoretical analysis shows that the simulation results are reasonable. The article covers the full research on such aspects as mathematic description, numerical analysis method and their practical applications. The diphase heating surface is divided into a hot water section, a evaporation section and a micro overheat section , the problems of model switching are avoided successfully between subcritical and supercritical working condition in the model of The diphase heating surface, and the model can be used for between subcritical and supercritical working condition without causing the model stiff infinity prick up problem. The mathematical model and dynamic characteristic account is unified and predigested for the diphase heating surface of once—through boiler under subcritical and supercritical pressure, and propose that the working conditions at phase change point could be used as divide criterion between water region and steam region under supercritical pressure, the problems are solved successfully between water and steam phase change point under supercritical pressure. The model not only using optimization design and engineering analysis of operational characteristic in power generation unit, and quantitative analysis and performance evaluation of system process, but also applying real—time simulation training to power plant run personnel.