Abstract: In view of the hydrodynamic characteristics of water-wall in ultra-supercritical pressure boiler,a hydrodynamic model was established for complicated series-parallel circuit system.The hydrodynamic calculation procedure was developed based on the POWERSTATION4.0 platform.According to the principle of equal exit temperature of working fluid,the throttle orifice plate compensating pressure drop was numerically calculated.The verifying calculation for mass flow distribution and pressure drop characteristics was carried out at a given heat load and designed throttle orifice plate.The hydrodynamic characteristic curve was drawn by Chebyshev polynomial fitting method.The vertical water-wall hydrodynamic characteristics of 1000 MW ultra-supercritical pressure boilers were also investigated numerically.The results show that U-type bifurcate tubes are good for the throttle orifice adjustment of vertical water-wall.The lower furnace of boiler has strong positive flow characteristics at low load rate but weak negative flow characteristics in supercritical load.The upper furnace of boiler has negative flow characteristics at different load rates.The curve of water-wall hydrodynamic characteristics increases monotonically,which means that the pressure drop of water-wall only depends on the mass flow.These results provide reliable theoretical basis for engineering design and operational monitoring of ultra-supercritical pressure concurrent boiler vertical water-walls.

Key words: ultra-supercritical pressure boiler, vertical water-wall, hydrodynamic characteristics

摘要： 针对超超临界锅炉水冷壁系统水动力特性,建立了适用于复杂串并联回路系统的水动力特性计算模型,基于POWERSTATION4.0平台研制了水动力计算程序。按出口工质温度相等的原则计算节流补偿压降;以给定热负荷和节流方式进行流量分配和压降特性校核计算,用Chebyshev多项式拟合法拟合水动力特性曲线方程。并数值研究了1000 MW超超临界锅炉垂直水冷壁水动力特性,计算结果表明:U形叉管有利于垂直水冷壁节流调节,低负荷率下炉膛回路具有较强的正流量特性,而在超临界负荷具有弱的负流量特性。上炉膛回路在不同负荷率下均具有负流量特性。水冷壁水动力特性曲线呈单值性。研究结果为超超临界直流锅炉垂直水冷壁的工程设计及运行监测提供了可靠的理论依据。

关键词: 超超临界锅炉, 垂直水冷壁, 水动力特性