液化搅拌过程混合性能的研究

Study on Mixing Performance of Liquefaction Stirring Process

为研究搅拌槽内液化过程的混合情况,以糙米粉溶液液化过程为研究对象,采用计算流体力学方法对3种搅拌桨的流场分布、混合时间、功率大小、剪切力大小等方面进行了模拟和分析。结果表明:倾斜大直径搅拌桨(ILD)与多叶片组合式搅拌桨(MBC)和最大叶片式搅拌桨(MB)相比有更强的径向混合能力,近桨叶处的径向速度相比多叶片组合桨和最大叶片桨增加4倍左右;倾斜大直径搅拌桨的死区占比最少,对物料的混合效果最好,在相同的操作条件下,倾斜大直径搅拌桨的功率降低了18%,在保持低能耗的同时,倾斜大直径搅拌桨平均剪切速率更大,更有利于非牛顿流体层流条件下的混合。

In order to study the mixing of the liquefaction process in the stirring tank,taking the brown rice flour solution liquefaction process as the research object,the flow field distribution,mixing time,power and shear force of three stirring paddles were simulated and analyzed by computational fluid dynamics method.The results showed that the large inclined straight-blade impeller(ILD)had stronger radial mixing ability compared with the multi-blade combined impeller(MBC)and the Maxblade impeller(MB),and the radial velocity near the impeller was higher than that of the multi-blade impeller.Compared with the multi-blade combination propeller and the largest blade propeller,the radial speed near the blade is increased by about 4 times.The dead zone proportion of the inclined large straight blade stirring paddle was the least,and the mixing effect of the material was the best.Under the same operating conditions,the power of the inclined large straight blade stirring paddle was reduced by 18%,while maintaining low energy consumption,the average shear rate of the inclined large straight-blade impeller was larger,which was more conducive to the mixing of non-Newtonian fluids under laminar flow conditions.