The Study Of Two-phase Flow Property In Axial-in Swirl Tube

With the increasing of air flow rate, the size of tangential-in cyclonewill be large and the dedusting efficiency will be low. Using the multi-tubeseparator is a way to solve the problem in the engineering. Multi-tubeseparators are widely used in the fields of energy, chemical, environmentalprotection and so on. It can be used in the general environment with hightemperature or high pressure and separate small particles efficiently. It isnot perfect in the research of the swirl tube which is the most importantpart of multi-tube separator. It is hard to make a study of the swirl tube wellbecause the flow in the swirl tube is complex. Keeping on exploring theswirl tube is important.In this paper, we provide theory for the design of swirl tubes bylearning the simulation of flow in the axial-in swirl tubes. The mostimportant in the study are the gas flow, gas-soild two-phase flow and theinfluence of operating parameter or structural parameter on the separationperformance of swirl tube.We build the geometric model of axial-in swirl tube by the software ofGambit. The computational domain and boundary conditions are specified.The proper computational grid was exported and make sure the grid isindependency. When calculate by FLUENT, it is based on the anisotropy ofLES model for turbulent flow, QUICK format for difference scheme,PRESTO format for pressure discrimination and SIMPLEC arithmetic for pressure-velocity coupling.It can be found that the mainstream is double vortexes in swirl tube byanalyze the gas flow. They are in the same rotation direction. It also can befound that tangential velocity and axial velocity are larger than the radialvelocity by analyze the three kinds of velocity distributed in the swirl tube.The tangential velocity is the most important. After that the paper analyzesthe loss of pressure in the swirl tube.Stochastic trajectory model in lagrange-coordinate system was used tosimulate the solid phase. Consider of the two-phase fluid coupling. Then bythe simulation of two-phase flow, the movement of single particle ispresented. Next, analyze the influence of operating parameters such as flowrate, particle diameter and particle concentration on the separationefficiency.The last, considering the influence about the diameter of vortex finder,the length of vortex finder and the structure of dust exhaust apparatus to theseparation efficiency in swirl tube.By numerical simulation, the characteristics of flow in swirl tubes canbe observed intuitively. It gives reference to experiments and theoptimizing of physical dimension in real life.