Diversion,Rectification And Drainage Of Strong Turbulent Flow Field

In this paper, numerical simulation about strongly swirling gas-solid flow field of Stairmand Cyclone Separators(abbr:SCS) was made using large eddy simulation method, considering the structure, improvements were proposed to separation situations like current disorder, Wagging tail, Back-mixing. Adding separator column and anti back-mixing cone in traditional separators to improve the flow field, steady vortex flow field perturbations. To verify the effect of additional column and anti back-mixing cone,numerical simulation and experimental study were carried out to study different subjects. Study focused on several aspects like vortex vector flow field velocity, pressure drop, turbulent kinetic energy dissipation, liquid tracer contrast, dynamic pressure pulsation test and so on. The affect on variation of cyclone flow field and separation performance was studied after adding additional inner member,offering further reference for micro and sub-micro particle capture and enhance cyclone performance optimization and hydromechanics theoretical basis to optimize whirlwind three-dimensional turbulent flow field. The main research works include:1.Numerical model was constructed by using mathematical modeling software gambit2.20 and calculated with fluid dynamics software FLUENT6.2 and the specific calculation method using large eddy simulation of numerical methods. Three-dimensional velocity field distribution, pressure distribution and the distribution of turbulent kinetic energy dissipation were analyzed between SCS and cyclone with additional components. The results showed that:under the same operating conditions 15m/s inlet wind velocity, the tangential velocity of the axial symmetry better adding internals, the maximum tangential velocity was low, but the separation zone wall separation speed did not reduce. SCS could achieve good separation effect. Display the vortex velocity vector diagram, flow column flow, good diversion effect, reduced the inner vortex and outer vortex interchange, eddy current disarray, regular vortex core end tail phenomenon. Additional internal components, turbulent dissipation was greatly reduced, the cyclone central turbulent dissipation to the biggest drop of 77%.2.Based on the gas flow field of the liquid tracer, comparing the adding inner component after the test. The Result show that adding the steady flow column, downward axial velocity attenuation degree was small, the vortex core end had enough energy to extend downwards. It reduced cones near the Tail phenomena, and this tool effectively reduced the truculence disturbance of the inner vortex and outer vortex.The column reduced turbulent energy dissipation.3.Under the same operating conditions, comparison of two kinds of separator pressure drop, total separation efficiency, particle classification efficiency and other performance effects, the results showed that, after adding internals, which made the separation efficiency of 1-5 μm particles increased 10%, and classification efficiency of 2 μm particles reached 75%. Although the pressure increased slightly, the cyclone separation internal pressure had not change. adding the steady flow column, it made the inner vortex rely on steady flow column rises, reducing the lower cone near the vortex Wagging Tail degree, anti reentrainment cone effectively reduced the ash bin mixing. They greatly improved the performance of cyclone separator.