Numerical Simulation Of Gas-Particle Two-Phase Flow In The Primary Air Channel Of Direct-Flow Pulverized Coal Burner

The coal burner is an essential part in the whole burning system of utility boiler, in which the characteristics of gas-solid two-phase flow play a very important roll for the efficiency and stability of coal burning in the boiler. If solid particle concentration, velocity and turbulent kinetic energy of each phase can be predicted accurately, the optimal design of structure and working condition of burners will be expected. Hence the concerning research has significant meaning for engineering applications. In this paper, by means of experimental measurement and numerical simulation, the study of cold-state gas-solid two-phase flow in a new-type of rich-lean direct-flow pulverized coal burner of a power station is carried out.Firstly, the gas-solid two-phase flow in the primary channel of pulverized coal burner is measured by means of 3D-PDA (Particle Dynamic Analyzer), through which the velocities, turbulent kinetic energies for both phases and the particle mass concentrations are obtained.Secondly, based on two-fluid turbulence k ?ε? kp model, the gas-particle two-phase flow in the primary air channel of pulverized coal burner is numerically simulated by using an own developed procedure, in which, in accordance with the hypothesis of dilute flow, the one-way coupling model is adopted to describe the interactions between the two phases, and the effect of particle diffusion is also considered in the solid phase equations.By comparing the experimental results with the computational results,some unreasonable factors in configuration of the burner are revealed. The mechanism of the gas-solid two-phase flow in the burner and the influence of the inner structure of burner on the flow field are discovered, such as the effect of"two elbow"structure and the function of the rhombi barrier.Finally, in this paper, based on the analysis of both results from experimental measurement and numerical simulation, the burner structure is optimalized, and the new structure is proved to be reasonable through numerical simulation.