流化床式筛分机中气泡特性的数值模拟

采用流化床式筛分机,针对煤料在流化床内流化时的鼓泡筛分特性,以Eulerian多相流模型,对筛分机的单粒径颗粒气固两相流动进行模拟,得出了筛分机内某一截面的固相体积份额分布图和不同截面的气泡分布图.为求证最佳流化速度,共设计了4组不同入口气速的工况.根据4组数值模拟结果,分析得出筛分机内最佳流化速度为0.96m/s.通过比较4组工况的流化效果发现,当流化速度为1.36m/s时,气泡最多,因而该工况最具有代表性,可用来研究筛分机的鼓泡特性.研究结果表明,筛分机的鼓泡具有随机性和不均匀性.

Numerical Simulation on Bubble Features in Fluidized Bed Type Screening Machine

Aiming at the characteristics of bubbling and sieving of coal in fluidized bed type sieving machine,based on a Eulerian multiphase flow model,the gas-solid flow of single particle size in sieving machine was studied by numerical simulation.The solid phase volume share distribution on a cross section and the distribution of bubbles on different cross sections in sieving machine were acquired.In order to identify the optimum fluidization velocity,four working conditions with different inlet gas velocity were designed.According to the simulation results of the four groups,the optimum fluidization velocity(u=0.96 m/s) was concluded.By comparing the fluidization effect of the four groups,it is found the number of bubbles is the largest when fluidization velocity is 1.36 m/s,so this working condition is the most representative to study the bubbling characteristics.The results show that the bubble in sieving machine is of randomness and nonuniformity.