Matlab-Based Numerical Simulation On Gas-Solid Two-Phase Flows In Cyclone

There is strong 3D rotation and high-intensity turbulence of two-phase flow in the cyclone, and the flow pattern is very complicated, so it is very difficult to predict its internal flows by doing an experiment or using analytical methods. Due to the limitations of experiment, it costs long time and fare just to study the cyclone performance by doing a simple experiment. Currently, it is a very important tool to study the cyclone with the technology of simulation by computer.During the simulation process of gas-solid flow in cyclone, it involves many of the arithmetic problems, such as: mesh, linear interpolation, three diagonal multiply algorithm (TDMA), iterative algorithm of algebraic equations, the numerical solution of the non-stiff differential equations with initial conditions, the visualization of velocity distribution, and so on. It is very tedious to solve these mathematical problems, so it is very important to choose a right program language and numerical processing software. Previously, we used FORTRAN, BASIC, and other languages mostly; they are not flexible in program control and not powerful in language function, which is more obvious especially in matrix calculation or graph-showing. Now, it reduces the difficult of software development in the flow simulation, with a high efficient compute language based on matrix and array - MATLAB.The flow field in a cyclone has been simulated based on MATLAB, and the standardκ-εturbulent model and SIMPLEC method with collocated grid were used to simulate the gas-solid flow. Functions which are built-in or programmed into MATLAB were directly invoked. Within a while expression, inner and outer iterations were readily constituted and it was found to be easy to invoke the plot commands to plot figures of the velocity distribution and the particle track in a cyclone.By doing the research of MATLAB-based simulation on gas-solid two-phase flows in cyclone, the result is compared with the previous experimental result, which has validated the feasibility and the accuracy of the program, and it also reveals the characteristics of the flow field in cyclone: the tangential velocity is double vortex-external natural vortex and internal mandatory vortex, which can be divided by the maximum tangential velocity; the axial velocity can be divided into outer up flow and inner down flow; the particle trajectories are complicated with a lot of randomness, especially small particles, they are greatly affected by the incident size and location of the particle. These research results can provide a theoretical basis for the cyclone optimization design.