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采用CFD法分析填充单一粒径和不同粒径颗粒固定床内的压降。分别采用PFC3D和Fluent软件建立固定床模型和模拟计算压力场,床层内颗粒流动雷诺数Re_p介于1~2 200之间。将床层空隙率、压降等模拟结果分别与已发表文献中的半经验公式的计算结果进行了比较,发现当Re_p小于120左右时压降的模拟结果与半经验公式计算结果基本吻合;而当Re_p较高时,二者之间的偏差较大;大颗粒使床层内空隙率分布的峰位置向固定床中心移动,第1个峰的位置与固定床壁面之间的距离和颗粒的质量平均直径(d_(43))值基本相同;采用d_(43)代替半经验公式中的粒径参数,得到的压降计算结果与模拟结果更加吻合。
The CFD method was used to analyze the pressure drop in single bed and fixed bed with different particle size. PFC3D and Fluent software were used respectively to establish a fixed bed model and simulate the pressure field. The Reynolds number of particles in the bed was between 1 and 2,200. Comparing the simulation results of void fraction and pressure drop with the calculated results of semi-empirical formula in published literature respectively, it is found that when Re_p is less than about 120, the simulation results of pressure drop are in good agreement with the results of semi-empirical formula. When Re_p is high, the deviation between the two is large. The large particles move the peak position of the distribution of void content in the bed to the center of the fixed bed. The distance between the position of the first peak and the wall of the fixed bed, The mass mean diameter (d_ (43)) values are basically the same. Using d_ (43) instead of the particle size parameter in the semi-empirical formula, the calculated pressure drop is more consistent with the simulation results.