Numerical simulation on the particle impact characteristics to the water wall of a boiler with four-wall tangentially firing

Abstract:

To get the particle impact characteristics of the water wall, numerical simulations on a 660 MW supercritical tangentially coal-fired boiler were performed based on Ansys Fluent. The impact mass flow value on the water wall in burner area was gotten by using Fluent erosion wear model. By using the Sample function of Fluent and Excel data processing function, how much the maximum velocity and how the velocity of particles distributes were obtained. The result indicates that the maximum mass flow value of particle impacting contralateral water wall area of burner nozzle is 6 kg·m^-2·s, the maximum velocity of particles impacting the water wall in burner area can exceed 30 m·s^-1 at a rate of 3%, the subject of velocity value is 5 ~ 20 m·s^-1, and particles with a speed from 20 m·s^-1 to 25 m·s^-1 may accounts for 10% of the total. It also shows that the 6 kg·m^-2·s high impact mass flow value and the 25 ~ 29 m·s^-1 high impact velocity coexists on the back wall in the second burner group area, where severe erosion wear may occur.