Solid Flow In The Swirl Burner Numerical Experiments

Nowadays, swirling burners have been used widely, because they can establish central recirculation bubbles which make high temperature gas flow back so as to speed up the progress of combustion of pulverized coal. In order to character the gas-solid two-phase flow in a swirling burner, this thesis studies two-phase flow in it with Numerical Simulation deeply.Firstly, it describes briefly the characteristics of a swirling burner and the two-phase flow. After the study of the international and domestic works on gas-solid two-phase flow about swirling burners have been introduced and analyzed detailed, both of the objects and the methods of this paper have been established.At the same time, it presents three turbulence models (standard k-?model, Renormalization Group k - ?model and Reynolds Stress Model) which have been used widely at present, and then their merits/shortcomings have been compared while being used to calculate swirling jets. When dealing with a low swirl number flow, the results by Renormalization Group (RNG) k - ?model agree well enough with experiments, so we do not have to apply Reynolds Stress Model (RSM). But when the swirl number is high, we have to resort to RSM, because of the obvious differences between experimental and numerical results by the models based on "effective viscosity". Fluctuating-Spectrum-Random-Trajectory (FSRT) model is used to solve two-phase flow.To solve the equations of gas phase, SIMPLE method is used.Besides, in this paper, the velocity distributes and recirculation areas of two phases are shown, and the differences between simulations and experiments are diminutive. Turbulence kinetic energy (?, turbulence dissipation rate (e), Reynolds stress and turbulence intensity are also simulated to reflect turbulence flow.For the Dual Register Burner, while CAT being applied, it simulates the influences of the flow field in the burner by changing the velocities of primary flow and inner/outer secondary flows, and by changing the opening percents of inner/outer vanes. Eventually, the appropriate values for velocities and opening percents of vanes are recommended, to provide engineering problems with theoretical orientations.Finally, the concentrations of pulverized coal also have been calculated, with Average-Volume Method. Coal solids' random tracks of different diameters are trailed.