Numerical Simulation Analysis Of Flow Characteristics In The Gas-solid-ejector

Pneumatic conveying technology always attract researchers’ attention due to its high transmission efficiency, simple equipment structure, convenient maintenance management, easy to realize automation and it is favorable to the environment protection and so on. Gas-solid injector, as the key equipment in the pneumatic conveying system, its job characteristics will get more attention by researchers.A kind of concentric ejector was put forward abroad due to the shortcoming that material easy to agglomerate even cause congestion near wall of the traditional ejector. The different place is that:solid materials is scored horizontal, open air vents ring in side, air and solid phase were scored from the same direction. The concentric ejector can be used as power source of a pneumatic conveying system because of its characteristics, this can fully utilize its head and suction, and traditional ejector can be used as the feeder of a pneumatic conveying system.But pneumatic conveying system involves some classic two-phase flow problem such as particles conveying in the pipeline and ejector. Two-phase flow hasn’t been had perfect theoretical calculation method because of its complexity, which largely limits the development of pneumatic conveying system. In order to improve the safety and efficiency of conveying particles and energy saving, in this study, numerical simulation method was adopted, with the help of ANSYS-FLUENT package, the influence of the operating conditions and geometry parameters changing on pneumatic conveying system performance was investigated from the flow structure changing point of view, which provide the reference and practical guiding significance for structure design and calculation of gas-solid ejector.The main research studies contained in this paper are as follows:1. Choosing suitable turbulence model and reasonable solve strategies, referencing the theoretical calculation methods, tube multiphase flow was analyzed by numerical simulation, we got the horizontal, and it was compared with the experimental value.2. Choosing suitable turbulence model and reasonable solve strategies, minimum transport gas velocity in vertical pipeline was calculated by numerical simulation.3. Multiphase flow was analyzed by numerical simulation in siphon, the influence of curvature radius and gas speed on pneumatic conveying was analyzed, all above provide reference to reduce the bending tube wear.4. The influence of nozzle position, contract angle and supply air volume on conveying effect was discussed by the numerical simulation of traditional gas-solid injector, which provides reference for the structure design calculation of the traditional pneumatic conveying ejector.5. The conveying effect advantages of concentric ejector compared to traditional projector was discussed by the numerical simulation of concentric gas-solid ejector. Then the concentric ejector with contraction was analyzed and the influence of contraction on static pressure distribution in ejector was discussed.The internal flow field in pneumatic conveying pipeline and two kinds of pneumatic conveying ejector was researched in this paper, influence mechanism of operating conditions and geometry parameters changing on pneumatic conveying system performance was deeply realized, and the dilemma that the lack of theory method on internal particle flow mechanism of the pneumatic conveying system was solved.