Numerical Simulation And Optimum Design Of Spiral Cyclone Separators

The spiral cyclone is a new type of cyclone. Its main character is that there is a continuous spiral channel with some turns inside the cyclone body, so a reasonable gas flow field can be formed which is advantageous for particle separation. Experimental studies have demonstrated that spiral cyclones have significant advantages of higher collection efficiency, lower pressure drop and smaller geometry dimension than conventional cyclones.In the first part of this paper, the two-dimension gas-flow field in the spiral channel is simulated numerically. The gas flow field is obtained by solving the N-S equations along with turbulence model; and particle trajectories are obtained by solving their momentum equations. The purpose of this simulation is to get the first impression of flow field features in a spiral cyclone, and to get the experiences of geometry construction and grid generation.For some reasons, experimental study has not been carried out in this paper. To validate the effectiveness of numerical method, the simulations of the gas flow and particle separation in conventional cyclones are performed. Comparisons between the numerical results and experimental data have been made and it is shown that there are reasonable agreements. This investigation can also provide the experiences about numerical schemes selecting, which is helpful for the next three-dimension simulation of the performance of spiral cyclones. These work of validation are specified as an individual chapter, which becomes to be an indispensable part of this paper.After these above preparations, a numerical solution strategy for the simulation of three dimensional gas-particle flow in the spiral cyclone can be constructed. For the existence of validations described above, results from these numerical simulations can be considered to be reliable. In this paper, we have calculated the two-phase flow in many spiral cyclones with different operating condition and various geometrical dimensions, and the effects of them on the spiral cyclone performance are discussed.Based on theory analysis and on the above numerical results, we construct the semi-empirical function expressions of particle collection efficiency and pressure drop coefficient. These expressions play an important role in the model of optimum design of configuration size of spiral cyclones—in the last part of this paper, we have discussed the method of constructing the optimum model from the view of mathematical programming, and the content includes: the establishment of objective function, the choosing of design variables and the specification of restriction conditions.