Numerical Simulation And Test Of Gas-particle Separation Property Of Axis-in Cyclone Separator

The axis-in cyclone separator which discussed in this paper is a typical axial-entrance cyclone, the inlet air can be three times more than the ordinary one and also airflow steady distributed. This kind of cyclone has a small size, high efficiency, big airflow and so on. Presently, This type of cyclone is used in the ventilation system on the train in the form of multiple tubular cyclone,but there is just very little research on this type of separator. Therefore, it has a broad meaning of the numerical simulation and experimental study on this type of cyclone .First, the flow field and pressure field are researched with a numerical simulation to the gas phase in the cyclone. zoning structurization grid method is used for the grid division, Reynolds stress turbulence model is used for continuous model, QUICK discrete format is used for convection, SIMPLEC algorithm is used for the pressure-velocity coupling, and pressure interpolation format is used for pressure discrete form. The calculation results on gas phase flow field shows that the flow field in the axis-in cyclone with a good symmetry and certain regularity: the mainstream in the axis-in cyclone is double-flow. with the zero-speed axis wrap as interface area, the external flow field of the cyclone is revolving downward, and the internal flow field is revolving upward, and their directions of rotation are the same, which is the same as the ordinary cyclone on the mainstream characteristics. However, for the existence of prerotation vane, the local secondary vortex cyclone in the mainstream is less than in the ordinary cyclone, and the distribution of the flow field is more symmetrical than that of ordinary. By changing the helix angleθand the leaf margins h₁ it has been five different numerical simulation models. The five models are calculated under the same entrance speed , analyzed their velocity field and pressure field, analysis of the effect of helix angle and leaf margins to the internal flow field and pressure field of the cyclone.When the flow field of the continuous phase is stabilized, by adding discrete particle phase into the steady continuous phase, the turbulent two-phase flow is calculated. One-way coupling is used for the numerical calculation on the two-phase flow , random orbit model is used for discrete particle phase. the result shows that the particle motion is extremely complex in the axis-in cyclone separator , it has a great relationship on the separation efficiency and particle size. Generally speaking, the larger particle size, the higher separation efficiency. Helix angleθand the leaf margins h₁ has a clear impact of on separation efficiency. In general, the smaller the helix angleθ, the higher separation efficiency. On this paper in terms of a high degree of separator, the greater leaf margins h₁, the lower separation efficiency.Finally, comparing a typical numerical simulation results to the test results, it validates the reliability and accuracy of the results of numerical simulation ; At the same time,the summary of this paper, analyzes the main dimension factors that impact the cyclone performance, points out the advantage and disadvantage of the five different models and provids valuable theory practice for the production.