Numerical Simulation On Flow Field Of Gas Phase Of Vertical Section Double Feed Inlet Cyclone Separator

Cyclone separator is a kind of equipment which separates the solid particles from the gas-solid flow by centrifugal force resulted from the revolving movement of the gas-solid flow. It is the key component that makes the CFB operate continuously and is also widely applied in the industry .The importance of developing the CFB and the role that the cyclone separator plays in the CFB are summarized. Present researches about the design, theory and experiment study of cyclone separator are analyzed in this paper. Numerical simulation method is found to be an important method for studying the cyclone separator flows.Numerical simulation method is finally selected to be the computing method by comparing the numerical results obtained by using different turbulent models, different format of difference and the pressure interpolation with the experimental results. The grid division of the computation area and establishment of the boundary condition under the boundary fitted coordinate are introduced. Numerical simulation of flow field in the cyclone separators is carried out with two different inlet forms.The gas flow fields in traditional single inlet separator and a new one-vertical section double inlet cyclone separator are simulated numerically under various operating modes by using the commercial software FLUENT 6.1.22. The gas flow field distribution, the pressure drop distribution, the relations between current capacity and pressure drop , the turbulent kinetic energy and the diffusion and different sub-whirlpool in ring space of two kinds of cyclone separator are contrasted. Results show that:(1) The ideal computation results of the complex flow field in cyclone separator can be obtained by using turbulent model (RSM) for aeolotropism, QUICK format of difference and the PRESTO pressure interpolation form based on high quality grid.(2) The mainstream is double-decked eddy in the cyclone separator, downward revolving eddy outside and upward revolving eddy in the center. And the orientation of all the rotations is the same. The air-path is dissymmetrical, the vortex core bias and short circuit air current of the vent-pipe is big for traditional cyclone separator. But it is reverse for the new one. The new type of separator is superior to the traditional single inlet separator in separation efficiency.(3) The resistance characteristic of the two kind of cyclone separator has been contrasted in this paper. It indicates in axis the pressure field is symmetrical in new double-inlet separator. This symmetrical distribution of pressure field is advantageous to improve separating efficiency and decrease pressure loss.(4) there are secondary turbulent flows nearby the roof and partial secondary turbulent flows in wall place nearby the vent-pipe. The partial secondary turbulent flows are small. They change and present the non-axial symmetry distribution circumferentially in traditional separator. But these kinds of secondary turbulent flows decrease, and the flow symmetry is very good under the same processing capacity in the new double-inlet cyclone separator. All these are advantageous to the gas-solid separation of the cyclone separator.The results indicate that the new vertical section double-inlet cyclone separator is superior to the traditional one in flow field structure, separation efficiency and pressure drop. The new kind of separator holds important engineering research and development value as a new structural style.