Numerical Simulation Of Temperature Field And Fluid Field Within The Direct-fired Hot Smoke Stove

Direct-fired hot smoke stove is the output device of the hot flue gas. It uses fuel direct combustion and output after dust fall purification, mixed cooling treatment. Direct burning stove has the advantages of high fuel efficiency, the output of hot air temperature adjustment range, simple equipment and long life. So it is widely used in drying materials which have high moisture content, large capacity, and are not afraid of contaminated, such as sludge, bad residue classes, lignite, a variety of ore. The internal temperature and the flow field of hot smoke stove can be obtained by numerical simulation, which proved that the result was realistic, compared with the actual production. These results provide a basis for improvement and optimization of the hot stove structure.This paper mainly simulates two aspects from the gas phase to the discrete particulate phase. And the gas simulation results provide reference for particle discrete analog. Particle discrete simulation needs to use the turbulence model, non-premixed combustion model, radiation model, the energy equation, the discrete phase and continuous phase coupling model. It selects the SIMPLE algorithm, and also sets the velocity inlet as well as pressure outlet boundary conditions to get the temperature contours, velocity contours, pressure contours and particle trajectories. Through the analysis this article concluded that:the high temperature combustion zone is the entrance place of the main and secondary wind, because this region has more volatiles, and then it burns more intensely; vice combustion chamber temperature is relatively lower; the temperature of the settling chamber is affected by the particle radiation; in the main and vice combustion chambers, airflow turbulence is more intense and its speed is quicker; the flow velocity of the settling chamber is relatively bigger; the entire furnace works in a slightly negative pressure state.To change the structures of the hot smoke stove is that:increase the height of the wind wall; reduce the wind wall; widen the main combustion chamber; increase the three fill vents. To change the operating parameters of the hot smoke stove is that:increase the amount of secondary air; adjust the excess air ratio of primary and secondary wind; reduce the amount of pulverized coal combustion and change the excess air ratio; increase the amount of pulverized coal combustion and adjust the excess air ratio. Compared to previous simulation results, this article concluded that:if it increases or decreases the height of wind wall, the temperature of the combustion zone will be raised; if it widens the main combustion chamber, the temperature of the combustion zone and the hot flue gas outlet will be raised; enhancing the secondary combustion excess air ratio and opening three fill vents on the sidewall would help improve the temperature of the combustion zone and the hot smoke outlet; the excess air factor of1.2to1.4can reduce the temperature of the combustion zone, and improve the hot flue gas outlet temperature as well as fuel combustion utilization; increasing the amount of pulverized coal combustion can improve the combustion zone temperature and supply heat.