磷酸反应槽内临界离底悬浮转速的CFD模拟

CFD simulation of critical suspension lmpeller speed in a phosphoric acid reaction tank

使用计算流体软件Fluent对磷酸反应槽内颗粒的临界离底悬浮转速进行了数值模拟.搅拌槽直径.T=0.5m,四块挡板均布,搅拌桨采用45°斜叶桨.两相物系为磷石膏—硫酸,固体体积百分比浓度φ=4.65%.使用浓度判据得到颗粒离底临界悬浮转速NJS,模拟计算结果的误差在工业允许的范围内.模拟得出搅拌槽中液体的流动状况和固体体积分数的分布;同时对6个不同搅拌转速下的固体颗粒悬浮状况进行比较,得出均匀悬浮临界转速.

Based on the function provided by Fluent,the critical suspension impeller speed,Njs,in a phosphoric acid reaction tank was simulated.The investigation was carried out in a fully baffled,flat bottom,cylindrical vessel with 500 mm diameter,equipped with PBT impeller.The phosphogypsum of 4.65% was chosen as the dispersed phase.The original criterion was used to determine Njs from the numerical results,and the error of simulation is acceptable to the industry standard.Solid concentration distribution and the velocity distribution of solid and liquid were predicted.The performance of solid suspension under the different agitation speeds was also studied,the critical suspension impeller speed was obtained.