Dissertation > Industrial Technology > Energy and Power Engineering > Steam Power Engineering > Steam boiler > Various types of boilers

Numerical Simulation on the Dense GAS Solid Multiphase Flow and Combustion Process in the Circulating Fluidized Bed

Author ChaXuDong
Tutor FanJianRen;ZuoKeFa
School Zhejiang University
Course Engineering Thermophysics
Keywords High concentrations of gas-solid flow Particle phase in the direct simulation Fluidized bed combustion simulation W furnace combustion
Type PhD thesis
Year 2002
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The work is mainly on numerical simulation of dense gas-solid two phase flow and the combustion and pollutant emission processes of circulating fluidized bed and W-shaped furnace applied by power plant.We successfully apply the two-fluid model(TFM) to the study of two dimensional and three dimensional dense gas-solid flow characteristics. The results show some rules on the particle collisions and gas particle interactive influence of the vertical upward pipe. And also we study the bubble flow behavior of the bubbling fluidized bed. The single bubble and continuous bubble formation, rise, break and coalesce characteristics are studied separately and compared with the experimental data. It shows good consistency. Then we apply the approach of Direct Particle Simulation (DPS) to the simulation of soft sphere model and hard sphere model by innovatively combining the different method of dealing the particle collision algorithm of hard and soft sphere model. We also calculate the different cases with the two approaches.On the base of the study of dense gas-solid flow, we make full-scale numerical simulation on the combustion and pollutant emission processes of the 75t/h circulating fluidized bed(CFB) which is developed by our institute. We draw the conclusion on the characteristics of flow field, particle track, temperature profiles and species profiles. We also study the characteristics of coal combustion and NOX formation and the interactive influence between them.Finally, we study on the characteristics of coal combustion and NOX formation of W-shaped furnace. It is a newly developed low pollutant emission and high performance combustion technology. We hope our conclusions may be helpful on the design and operation of the W-shaped furnace.Our work is only an attempt about the study on the dense gas- solid flow and combustion technique of CFB and W-shaped furnace. The results testify the accuracy and efficiency of the numerical simulation method (or Computer Aided Test method ) on the prediction and validation of the engineering flow and combustion problems.

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