Simulation And Visualization Of The Particles Motion In A Fluidized Bed Boiler

The circulating fluidized bed (CFB) boiler combustion technology has been rapiddevelopment in recent years, because of the feature of high efficiency and low-pollution.This technology has many advantages, but the abrasion problem constrains its development.In this paper, on the basis of summing up the characteristics of the CFB boiler, as well asthe advantages and disadvantages, study on the law of motion about material particles inthe CFB boiler is proposed.First, this paper introduces the progress of the materials movement in the coldexperiments and simulation about the CFB boiler. And determine to use the Fluent softwareto simulate the cold experimental table and utilize two high-speed cameras placed in thevertical direction to track particles in the test.Reasonable simplification of the experimental table model in the Fluent simulationprocess to shorten the calculate time. In simulation the gas-solid interphase drag forcemodel select the EMMS model,but the fluent software does not contain the EMMS model,so in this paper write a UDF about the model and load into fluent. The simulation resultsshow that in the process of materials movement, the trajectories of material particlesconstantly changing with the growing of air intake. When the wind is stable, there emergethe double core-annulus structure in the bench. And the wind speed the greater the longertime to reach steady state of motion about mateialr.In order to more clearly record the trajectory of particles using the shooting speed of240frames per second and add the tracer particles in the materials. Divide the videos of thetwo high-speed cameras into pictures, and then synchronize the pictures of the two videos.Use the getdata graph digitizer software to identify the coordinates of the target particles.Translate the data into actual space coordinates and draw the trajectory image. This paperanalyze the particles’ trajectory and find that the parabolic shape is present in the particletrajectory at a certain height, and the core-annulus structure can be seen in the video. Thelaws of particles motion with the simulation results are basically same. However, thesimulation uses a simplified, so the particle trajectories are slight different. The numerical simulation results and the cold experimental results verify each other, and they complementeach other at the same time.