Through study on secondary vortex in flow field of the furnace for six-conrner tangential firing boiler with a height-length-width ratio

it has been found that the formation of secondary vortex must satisfy three conditions.Although the secondary vortex can strengthen combustion reaction in the furnace

making utilization of space in the furnace to be more sufficient

and being helpful to control the unburned combustibles in fly ash and to control the NOx emission

at the same time

however

it is easily to result in impefect combustion and slagging on the high-temperature heating surfaces.Regarding to this

fundamental method for prenventing secondary vortex at the corners has been put forward

i.e.adopting burners' arrangement modes

such as four-corner tangential arrangement or dualfurnace tangential arrangement

to enhance the rigidity of primary and secondary air jet

and arranging cross-wind around the burners

to weaken the condition for producing secondary vortex

the rotating intensity of main rotary gas flow in the furnace has been strengthened

the substances in the furnace are basically forced to move as the mode of main rotary gas flow.