一种新式搅拌器的设计与实验研究

提出一种新的搅拌器--筒式搅拌器的设计方法,介绍筒式搅拌器的结构和工作原理,对筒式搅拌器的搅拌扭矩进行实验和分析,并与推进式和涡轮式传统搅拌器进行比较.实验表明,在同等工况下,筒式搅拌器的扭矩小于推进式和涡轮式搅拌器的扭矩,其搅拌功率准数也远远小于推进式、涡轮式的.因而,该研究对于提高搅拌效率和节能具有重要的意义.     

新型行星式搅拌器开发及性能研究

介绍了新型行星式搅拌器的结构和设计原理。该新型搅拌器有一个传动轴和数个行星叶轮组成,行星轮自转的驱动力来自液体阻力,行星叶轮自转速度的大小与公转速度、公转半径和自转半径有关,而与行星叶轮高度无关;自转方向与公转方向相反。测试采用IKA EUROSTAR power control搅拌装置和Labword软件,试验介质为水和甘油。通过对搅拌器的搅拌性能试验研究发现,流体质点的轴向流线为高速螺旋线,主要流型为径向流和轴向流,因此,在主轴转速较低的情况下被搅拌液体亦可获得满意的混合效果。通过对试验数据分析处理,得到测试用行星式搅拌器的功率准数、混合时间数、排液量和循环量等搅拌性能曲线及经验公式。     

24种搅拌器的功率曲线

文章对有挡板条件下常用的桨式、涡轮式、折桨式、推进式搅拌器采用桨槽径比为0.4—0.6,大于传统的1∶3的结构参数,还有双层桨的形式,进行搅拌功率曲线的测绘。另外对桨叶上开孔、管形桨、弧面桨、半管形桨的正、反两面进行搅拌器的功率曲线测绘,共24条曲线。详细介绍了功率曲线测绘设备的结构形式和各种参数比,以供设计搅拌器时使用;说明了较大的桨槽径比及双层桨叶在实际生产应用中的重要意义,对不同结构搅拌器的功率准数进行了对比,并说明了应用NP-Re曲线的注意事项。     

非牛顿流体在过渡流域的搅拌功率和混合效率

研究了六种搅拌器在过渡流域的混合特性,测定了功率消耗和混合时间,用混合效率准数C_4选择适合于过渡流域混合的搅拌器。研究发现:丰椭圆板——导流筒和MIG——锚搅拌器适合于过渡流域的混合操作,尤其是MIG—锚搅拌器具有很高的混合效率,值得向工业部门推荐。实验还同时测定了这六种搅拌器和复动式搅拌器在层流域的功率消耗和混合时间,发现复动式搅拌器混合效率最高。     

行星轮式搅拌器搅拌特性分析

介绍行星轮式搅拌器的结构与工作方式。采用计算流体力学对比分析了行星轮式和普通式搅拌器的流场速度,结果表明:行星轮式搅拌器比普通式搅拌器的搅动范围更广,形成的循环可涉及到整个搅拌釜,且搅动更均匀无死角。使用Adams软件分别对三行星轮、二行星轮的三叶片式和二叶片式搅拌器进行模拟分析,剖析了叶片的运动轨迹,结果表明:三行星轮三叶片式的叶片偏置角为40°时,覆盖度为95.7%;三行星轮二叶片式的叶片偏置角为60°时,覆盖度为85.0%;二行星轮三叶片式的叶片偏置角为60°时,覆盖度为60.0%;二行星轮二叶片式的叶片偏置角为90°时,覆盖度为53.0%;四者中,三行星轮三叶片式搅拌器的搅拌效果更优。     

半椭圆板-导流筒搅拌器的功率消耗和混合效率

对牛顿流体和非牛顿流体,在层流域和过渡流域测定了三种不同结构(A、B、C型)的半椭图板-导流筒和双螺带-锚搅拌器的功率消耗、Metzner常数Ks和混合时间T_M,用混合效率准数C_4(=T_MW_V/μ)比较了它们的混合效率。结果发现:在上述搅拌器中,A型搅拌器的混合效率高于双螺带-锚搅拌器,并有可能取代造价高的螺杆-导流筒搅拌器。     

不同类型搅拌器的气—液分散和混合特性

在通气式搅拌槽内研制了直叶圆盘涡轮、直叶桨式涡轮、４５度折叶圆盘涡轮、４５度折叶桨工涡轮、凹弧叶圆盘涡轮、锥形涡轮和布鲁马金式搅拌器的临界分散转速、分散状态、搅拌功率、气含率、气泡停留时间、排量准数和输出效率，并获得了适用上述种类搅拌器的临界分散转速、搅拌功率、气含率和气泡停留时间关联式。     

筒式搅拌器性能试验研究

介绍了获得实用新型专利的筒式搅拌器的结构和工作原理,对筒式搅拌器的搅拌性能进行了试验研究和分析,并与推进式搅拌器和涡轮式搅拌器进行了比较。试验结果表明,3种搅拌器在同等条件下,筒式搅拌器的能耗最小,且其排液量和循环流量最大。     

酯化反应器内搅拌器的优化设计

搅拌功率和循环流量是考察搅拌桨性能和搅拌槽内混合效果的两个重要参数。作者在直径为5 0 0 m m和 80 0 mm的带导流筒的搅拌槽内 ,试验测试了现工业生产中酯化反应器内的搅拌桨的循环流量准数和功率准数 ,并根据工艺要求优选出以 CBY螺旋浆与直叶透平桨组成的双层浆式搅拌器 ,该搅拌桨比现工业用桨在消耗相同功率的条件下能产生更大的循环流量     

齿盘式搅拌器的搅拌功率及混合特性

根据测定与关联计算,给出了两种齿盘式、60°双层斜桨式、平桨-耙式和双螺带-锚式等五种搅拌器在全流域中的功率曲线及其关联式、Metzner 常数K_8和湍流域(Re=7×10~4—3×10~5)的混合效率(θ_M～W_V)曲线。当 Re>10~5时,两种齿盘式搅拌器的功率准数Np分别为 0.129和 0.094;当 Re=7×10~4—3×10~5时,则在五种桨型中,以齿盘式搅拌器的混合效率最高。达到同样的混合效果,齿盘式搅拌器的耗能仅为通常用于这一流域60°双层斜桨式搅拌器的1/4。齿盘式搅拌器是一种值得推广应用的节能搅拌器。     

Effects of the Stirred Tank's Design on Power Consumption and Mixing Time in Liquid Phase

The influence of the stirrer type and of the geometrical parameters of both tank and agitator (clearance of an impeller from tank bottom, impeller diameter, draft tube and geometry of the tank bottom) on power consumption and mixing time in liquid phase under turbulent regime conditions (Re > 10⁴) have been studied. Different types of agitators have been used, namely Rushton turbine, 45° pitched‐blade turbine, MIXEL TT and TTP propellers and 1‐stage or 2‐stage EKATO‐INTERMIG propellers. All these stirrers were tested with the same power consumption per unit mass of liquid. On the basis of measured power consumption per unit mass, which is required to achieve the same degree of mixing, the results obtained in the present work show that the TTP propeller is the most efficient in liquid phase. Recommendations on the optimum geometric configuration have been made for each type of stirrer.     

筒式搅拌器及其开发

介绍了实用新型专利——筒式搅拌器的结构和设计原理。筒式搅拌器主要有筒体和内弯叶片组成,搅拌时能同时产生强大的径向流和轴向流,具有较大的排液量和循环流量,混合效果极强。筒式搅拌叶轮的各尺寸设计取决于液体性质、混合要求、容器直径和转速等因素。     

螺带式搅拌器在假塑液中的混合及放大的研究

本文综合研究了螺带式搅拌器在假塑性液体中的混合特性及动力特性，测定了双螺带，内外螺带及螺带螺旋３种类型搅拌器的功率常数Ｋｐ和Ｍｅｔａｎｅｒ常数Ｋｓ，并得出混匀操作和传质工艺过程的放大准则。     

组合桨搅拌器的宏观混合特性

分别以浓度为１％，２％，３％，３．５％的羧甲基纤维素溶液为实验，采用测温法，测定了正交双层三角桨－单螺带桨，正交双层三角桨－内外单螺带桨．锚式桨－三叶推进器．锚式桨－内外单螺带４种组合桨拌器的宏观混合时间，无量钢数Ｃ１，Ｃ２，Ｃ３，Ｃ４综合评判了它们的宏观混合性能，实验证明，前２种组合桨搅拌器在不同流域内都使搅拌介质达到良好的宏观混合，且功率消耗低，混合效率高，具有明显的节能优势，对搅拌变粘度体系     

聚合物溶解槽内双搅拌器流场特性的数值模拟

搅拌设备是目前海上油田实施聚合物驱油的配注系统的关键设备之一。利用计算流体力学方法对聚合物溶解过程采用翼型上推式搅拌器KCXU和锚式搅拌器MS的内外3种组合槽内流场进行了数值模拟,获得了搅拌器槽内的流场特性、循环流量及搅拌器的功率消耗。结果表明:在第1种混合状态时,KCXU搅拌器与转动的MS搅拌器组合时的流场变得更为复杂、无序。在第2,3种混合状态时,KCXU搅拌器与正转的MS搅拌器的组合形成的流场速度较大,加强了KCXU搅拌器的流动范围,并,且形成了最大的循环流量,其功率居中。     

计算多轴拌器的轴功率

对三种搅拌器：锚式、螺旋式、锯齿式，在不同的转速配比下进行了轴功率测试，搅拌雷诺数为０．８～３０００００，液体的粘度为０．００１～８４Ｐａ．ｓ。液体的性质属牛顿型流体，试验过程用计算机控制．通过测量轴的扭矩来确定搅拌器的轴功率。实验测定了不同情况下搅拌器相互之间的影响。实验数据由马跨特计算方法确定模型参数并给出层流至湍流范围内三种搅拌器轴功率的计算公式．     

Advantages of the hollow (concave) turbine for multi-phase agitation under intense operating conditions

The mixing literature on hollow blade turbines (HBTS), for operation in fully turbulent flow, is reviewed and compared with the results of our own studies. The SCABA 6SRGT is shown to have an almost identical pumping rate to a disc turbine, when compared at the same diameter and specific power. An equation is proposed for the effect of scale and blade geometry on the power number of a range of concave hollow blade agitators. The “flooding-loading” condition is revisited. It is found that, when compared at conditions above the minimum Froude number required to disperse gas, the HBT designs are as energetically efficient as Rushton turbines for dispersing gas. If we compare them on an “ungassed” power basis, as is the usual literature case, then the HBT is more efficient because of their ability to disperse gas without significant loss of power. The much lower power number resulting from the streamlined blade design of the HBTs also ensures that they achieve the minimum Froude number required to disperse gas at a much lower power than a RT. A simple method to avoid “flooding” for radial turbines, based on this work, is proposed. Under fully loaded conditions the hollow blade turbines will handle high gas rates without significant loss of power and this ability is a function of the degree of streamlining. For the suspension of high levels of solids the D=T/2 hollow blade turbines, at a clearance of T/4, are found to be amongst the most efficient agitators especially under gassed conditions, where almost no effect of gassing on the just suspension speeds were noted.     

Reduced IMRs in a mixing tank via agitation improvement

Mixing of Newtonian fluids in a stirred tank at low Reynolds numbers was investigated experimentally by means of a visual decolourization technique and shaft power measurements. The research was focused on the Isolated Mixing Regions (IMRs), which are “doughnut-shaped” structures in a stirred tank exhibiting little mixing with bulk of the fluids. The effect of Reynolds number on the IMRs was determined. The critical Reynolds numbers beyond which IMRs are destroyed were presented. The study was focused on agitation design which consumes less power input to destroy the IMRs. A pitch-bladed impeller with an alternating pitch was found more energy efficient than other test impellers in eliminating IMRs in both baffled and unbaffled configurations. It was also found that dramatic reduction in the power consumption could be achieved with installation of baffles to eliminate IMRs at typically low Reynolds numbers. The improved energy efficiency was thought related to generation of more chaotic mixing from the disturbance generated by the baffles, or impeller blade asymmetry such as alternating pitch. An energy parameter was introduced to account for the mixing time scale and the power required in regimes above the critical Reynolds number, in order to evaluate the energy efficiency when IMRs are non-existent.