Burn-in Cycle Based On Computational Fluid Dynamics Three-dimensional Numerical Simulation Of The Calciner

The thesis is based on a study of numerical simulation of flow properties in circular precalciner, which is study and application of the new type dry-process kiln system in plateau of "863"project. Precalciner is key equipment of the system of precalcination in the new type dry-process cement's production. In precalciner, the fluid parameters, such as concentration distribution, kinetic velocity, stay-time of materiel and fluid velocity, pressure and temperature distribution of gas-phase have a lot of relations to the properties of the combustion of pulverized coal and the decomposition of carbonate. The study aims is to study flow properties in precalciner and probe the close relation between the fluid parameters and the different structures and boundary conditions, the relation can be provided as the reference to improve its structure and operation.Based on Computational Fluid Dynamics, on Fluent 6.1, three-dimension gas turbulence flow was simulated by Realizable k - ε model in the circular precalciner from Taiyu company. The numerical simulation get distribution of velocity, pressure, turbulence and temperature. The result of numerical simulation was compared with the parameters of practical operation in the precalciner. The distribution of flow showed reasonably that the design of the precalciner is good. Based on the simulation of gas turbulence flow, the gas-solid two-phase flow of it was simulated by Mixture multiphase models. The results, such as the velocity, pressure, temperature and particle concentration are analyzed, which showed the precalciner is excellent.Based on the simulation of the practical operation and actual size in the precalciner, the gas turbulence flow and gas-solid two-phase flow were simulated by changing structures and boundary conditions. The result of simulation show that the inlet of CaCO₃ add stream of secondary jet, which was probed the distribution of flow velocity, particle concentration, intense of the turbulent flow on the hydrodynamics of gas-solid flow and the ability of the tangential and axial dispersion of CaCO₃. Thus, it will benefit the decomposition of CaCO₃ and the coal's combustion, and the stack problem will beavoided. That the result of numerical simulation compared with the parameters of practical operation in the precalciner, showed that the method of numerical simulation (CFD) is feasible to improve its structure and operation. Besides, the result of numerical simulation puts forward some information of operation. It has a significance of economy and society.