Abstract: Considering the complexity and variation of mixed system in many processes in industry,a novel large-double-blade impeller with wide adaptability was developed.A computational fluid dynamics model describing the flow and mixing process was built,and the power,flow field and mixing characteristics in a stirring tank equipped with the novel impeller were simulated and analyzed.The simulation results show that in the flow field produced by the novel impeller,there are local circulating flows in the upper and lower blade zone and overall circulating flow through the whole tank.As the viscosity of mixing system increases,the fluctuations of axial,radial and tangential velocities in the flow field decrease,and its power and mixing performance remain good,which indicate that the novel impeller has a wide adaptability to flow regimes and viscosities.For the novel large-double-blade impeller,it is not beneficial to the global mixing when the feeding point is located close to liquid surface,so the feeding between the upper and lower blades is recommended in order to shorten the mixing time.The novel impeller is more efficient than the FZ impeller with the same dimension under the same power consumption per unit volume,so it is more competitive in energy conservation.The simulation will contribute a lot to the improvement and optimization of the structure and operation of the novel large-double-blade impeller.

Key words: large-double-blade impeller, wide adaptability, power consumption, mixing characteristics, numerical simulation

摘要： 针对过程工业体系特性复杂多变的特点,开发了新型大双叶片宽适应性搅拌器,并建立了描述其流动、混合过程的综合数学模型,模拟分析了搅拌釜内的功率特性、流场特性和混合特性。模拟结果表明:新型大双叶片搅拌器所形成流场中存在着上部叶片区域循环流、下部叶片区域循环流以及纵贯全釜的整体循环流;随体系黏度增加,新型大双叶片搅拌器所产生流场的轴向速度、径向速度和切向速度均波动趋缓,且仍保持良好的功率与混合特性,对流态和黏度具有宽适应性;对新型大双叶片搅拌器而言,近液面加料方式不利于整体混合,适宜的加料点应在上下叶片之间,以缩短混合时间;在消耗相同单位体积功率的前提下,新型大双叶片搅拌器较同尺寸规格的FZ搅拌器的混合效率更高,具有高效节能的竞争优势。模拟结果对改进和优化新型大双叶片搅拌器的结构与运行具有参考价值。

关键词: 大双叶片搅拌器, 宽适应性, 功率消耗, 混合特性, 数值模拟