Numerical Analysis Of Heat Deviation With Flue Gas Side In Coal-fired Boiler Furnance

China is the world’s largest coal producer and consumer,China’s energy structure based on the rich coal and lack of gas and oil,lead to the pattern of our country formed mainly to coal.At present,the number of coal-fired boiler,coal fired power generation accounts for over 75% of the total generating capacity.And thermal deviation has been the main problems of coal fired boiler furnace combustion,it affect the safe and stable operation of the boiler.This paper is based on a 1000 MW ultra-supercritical coal-fired boiler tower as the research object,simulation of two-dimensional symmetric structure under asymmetric mechanism of boiler furnace flow within the three-dimensional boiler furnace on cold and hot state flow,the numerical simulation of heat transfer and combustion in the furnace,from the perspective of nonlinear explain the mechanism of formation of the internal heat deviation caused by furnace,and puts forward three kinds of improved furnace exit to the thermal deviation.Through the research work of this paper,for the future of tower type coal-fired boiler design and actual operation to provide theoretical reference data.The research results are as follows:1.Two-dimensional flow field and temperature field inside the furnace of the simulation study shows that under the laminar flow and turbulent flow model,with the increase of Re,inside the chamber of a stove or furnace development for asymmetric velocity distribution from the left and right sides is symmetrical,the velocity distribution in the static bifurcation,show the phenomenon of multiple solution,namely the nonlinear flow in the furnace exit near the water wall forming speed deviation on both sides.2.Simulation of cold working conditions is the chamber of a stove or furnace flow field.Simulation results show that the furnace structure symmetry in the flow model of the asymmetric flow field,the pulverized coal nozzle tangential is clockwise deflection,cut circle circle degree decreases,and the radius increases,tangential center deflection,asymmetry of velocity distribution;As the burner outlet air velocity increases,the velocity distribution in the hearth from symmetry to asymmetric completely,this may be the cause of furnace exit temperature deviation.3.Namely BMCR condition simulation the flow field and temperature field inside the furnace,with the simulation results show that the furnace temperature increase with the increase of the height of the hearth,and the upper area reached the highest temperature in hearth,namely the pulverized coal combustion in the upper burner area the most intense,high temperature,the boiler outlet temperature decreases,exist in the furnace outlet temperature deviation.Nonlinear flow in the furnace is,therefore,furnace exit form a influence factors of thermal deviation.4.From the perspective of nonlinear three advices to reduce tangential boiler thermal deviation method.By changing the Angle of burners,burner nozzle speed and a wind inlet temperature the furnace exit thermal deviation is reduced.The simulation results show that when the burner incidence Angle deflection 6°;Adjustment on both ends of the burner exit velocity,the boundary conditions are no longer symmetrical;Primary air temperature on the basis of the original plus 10 K are conducive to reduce export furnace thermal deviation.