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.