Experimental Research & Numerical Simulation Of Flow Field And Flame Blackness Of CWS Burner At Large-Scale Boiler

This article includes the coal-water slurry burner, jet combination of burner and aerodynamic characteristics of tangential firing in furnace. The coal-water slurry burner and jet combination of burner is analyzed by numerical calculation while the blackness of light diesel oil, heavy oil, pulverized coal and coal-water slurry brighten and half brighten flame is analyzed by the experiment and numerical calculation in the hot test bed and station boiler.The coal-water slurry burner is based on the straight and roational coal-water slurry burner (external straight flow and internal cyclone flow). In accordance to the effect of aerodynamic characteristics by the coal-water slurry burner, jet combination is made up with secondary air of rectangular snout and primary air of coaxial annular what is combined of direct flow and rotational flow in mixing chamber. ( straight primary air in the external ring and vortical center air in the internal ring)What indicated in the research is that the characteristic of aerodynamic in flow field is affected by the precombustion chamber, expanded exit, center air.In jet combination, the effect of secondary air to primary air incarnates through the spiral vortex extrusion in the initial section and transition section and the interflow injection in the root section. In the initial section of interflow, the sectional area of backflow region decreases while its length increases in the initial section and the root section and the shape of backflow region transform changes into erect elliptical from circle(the major axis of elliptical along the direction of secondary air).The quantity of reflux is changed. The maximal quantity of reflux decreases and the spread angle along the vertical direction to the jet combination of primary air decreases, too. The circle of contact takes on time averaged, instantaneity, periodicity and crumbliness in flow field of angle burner high length-with ratio furnace.The ash air can velocity in the exit of furnace by the negative tangential direction, what reduce the flue-gas temperature misalignment.Because the two-colour method only considered the effect to by the black carbon, it is not acceptable for the research of the blackness of half lighting flame. This article introduces the three-colour and four-colour method and do some further studies on the flame blackness by three-colour method and considers the flame to negative grey body. The flame blackness turns to be large and then small along the flame travel. The maximum value of soft coal, heavy oil and coal slurry flame blackness almost appears after the maximum temperature of flame. The primary conclusion is that: the soft coal flame blackness is 0.579~0.84;the CWS (made with soft coal) flame blackness 0.621 ~0.82; the heavy oil flame blackness is less than of soft coal and coal-water slurry; the major effect influencing factor of flame blackness is the triatomic gas, the coke particle and ash particle.