油菜籽流化床气体分布板结构参数优化

Structure-parameter Optimization of Gas Distributor for Rapeseed Fluidized Bed Dryer

为优化油菜籽流化床气体分布板的结构参数,根据欧拉(Euler)方法的双流体模型和标准k-ε湍流模型,采用计算流体力学(CFD)分析软件Fluent,对气体分布板的开孔率和布孔方式进行优化设计。结果表明:开孔率为15.84%圆形不均匀布孔的气体分布板是油菜籽流化床干燥的最佳气体分布板,增强了热空气的流通性,减少了局部区域的热空气聚集,实现了气粒两相流动的正常流态化,达到了流化床内油菜籽颗粒均匀分布,无沟流和死区的目的。通过实验,对模拟结果进行了实验验证,结果发现数值模拟与实验结果相吻合,证明了所优化的最佳气体分布板是合理可行的,为工程实践缩短油菜籽干燥时间提供了一种较理想的气体分布板。

In order to optimize the structure-parameter of gas distributor for the rapeseed fluidized bed dryer,the open porosity ratio and the arrangement holes mode of gas distributor were optimized through numerical simulation software of Fluent based on Euler two-fluid model and standard k-ε turbulence model. The results showed that open porosity ratio of 15. 84% and uneven circular holes arrangement were the optimized structure-parameters of gas distribution for the rapeseed fluidized bed drying,which enhanced liquidity of hot air,reduced hot air to gather in the local area,made gas-particle two phase flow normally fluidize,and achieved the homogenized distribution of rapeseed particle in fluidized bed without channeling phenomenon and dead zone. The simulation results were verified through the experiment. The drying kinetics curves of gas distributor of different open porosity ratios and arrangement holes modes were comparative analysis based on experiment data,which showed that the drying rate of gas distribution with open porosity ratio of 15. 84% and uneven circular holes arrangement was the biggest compared with the other types. Therefore,the gas distribution with open porosity ratio of 15. 84% and uneven circular holes arrangement was the optimum. The results of numerical simulation and experiment were consistent. The results testified that the optimized best gas distribution was reasonable and feasible. Therefore,the gas distribution is an ideal gas distribution to shorten the rapeseed drying time for the engineering application.