The internal flow distribution and combustion characteristics are greatly affected by the structure of spreader-stoker boiler

which is the main cause of poor combustion efficiency and environmental pollution.In this study

the physical and mathematical models of the internal flow field are established on the base of UG-35/39-M spreader-stoker boiler.And the effect of front arch angle on the cold internal flow field is studied.The results show that there is a steady recirculation zone above the front arch.With the increase of the front arch angle

the recirculation zone tends to decrease until it disappears.Within the experimental range

the internal flow works best when the front arch angle is 15°.The presence of the recirculation zone reduces the velocity of air

prolongs the residence time and enhances the air mixing effect in the boiler.The increased arch angle can improve the combustion and heat transfer conditions in the furnace.Meanwhile

it can aggravate the erosion of the furnace and adversely affect the safe operation of the boiler.