摇瓶反应器中流体流动的CFD数值模拟

针对250 ml摇瓶在回转式摇床上的流体流动,基于VOF模型、RNG k-ε湍流模型结合建立了描述摇瓶液体的流体动力学模型,并利用计算流体力学软件FLUENT和动网格技术对其进行了数值模拟。考察了不同转速和不同装液量条件的摇瓶内液体的流动状态,液相形状变化,液面高度,气液接触面积,液体总表面积的变化。模拟计算结果给出不同操作条件对湍流参数（湍流强度、湍动能、湍动能耗散率）和溶氧传质系数的影响,获得了湍动能耗散率与摇瓶转速和装液量之间的关联式。     

生物反应器内微载体培养细胞的胰酶消化放大技术

目的建立生物反应器内微载体上Vero细胞球转球胰酶消化放大技术。方法用500 ml搅拌瓶培养Vero细胞,待细胞浓度达1.8×106个/ml时,加入25和37℃消化液(0.25%胰酶+0.02%EDTA)消化不同时间,计算细胞回收率及细胞活率,筛选微载体细胞最佳培养温度及消化时间。将3 L反应器内微载体及T25方瓶培养的Vero细胞消化后接种T25方瓶,比较两种传代方式下的细胞形态及比生长速率。将3 L反应器内微载体培养的Vero细胞用消化液消化后,按1∶3、1∶6、1∶8、1∶10、1∶12的比例接种至15 L反应器,确定最适接种比例。将转瓶及3 L反应器内微载体培养的Vero细胞消化后接种至15 L反应器,比较两种放大方式下的细胞形态、密度及比生长速率。结果微载体上培养的Vero细胞经25℃消化15 min可有效保证细胞的回收率及活率。两种传代方式下的细胞形态及比生长速率无明显区别。细胞比生长速率在1∶6~1∶10比例放大时较高。两种放大方式下的细胞形态、密度及比生长速率无明显区别。结论初步建立了生物反应器微载体内细胞的胰酶消化球转球放大技术,Vero细胞存活率较高,贴壁良好,空珠率较低,可应用于生物反应器微载体培养系统的规模放大。     

红豆杉细胞反应器悬浮培养氧传质系数的研究

氧传质系数是表征反应器操作性能的重要参数,是反应器优化设计和放大的关键,植物细胞培养液中的氧传质系数与纯水或模拟溶液有很大差异,必须在实际培养过程中在线进行氧传质系数的研究。为了快速、准确地测量实际培养液的氧传质系数,基于动态法恢复通气后的溶氧质量浓度-时间数据,提出了确定氧传质系数和饱和溶氧质量浓度的新方法,进而测定了10 L通气搅拌反应器中红豆杉细胞悬浮培养过程的氧传质系数,研究了氧传质系数、细胞的摄氧率和细胞的比耗氧速率的变化规律。结果表明:通气量对氧传质系数的影响大于搅拌转速对氧传质系数的影响;随着细胞生物量增加,氧传质系数减少、摄氧率增加,比耗氧速率先增加后缓慢下降;建立了氧传质系数kLa与单位体积的功率输入N3D2和空气表观线速度vS的关联式和氧传质系数kLa与细胞生物量X的关联式。     

一株β-甘露聚糖酶生产菌细胞培养条件的优化

地衣芽孢杆菌SY-8具有分泌β-甘露聚糖酶的能力.为提高地衣芽孢杆菌SY-8的产酶能力,必须先找到该菌培养的最佳环境条件,因此考查温度、摇床转速、传代浓度、培养pH、渗透压等因素对细胞生长状态的影响,发现当温度为30℃,摇床转速为100 rpm/min,传代浓度为1.25×106 cell/mL,细胞培养pH为6.5,渗透压为360 osmol/g时,能达到SY-8细胞培养的最佳条件,有利于满足大规模培养的需要.     

适用于动物细胞培养的搅拌桨及其数值模拟

提出了一种方法考察桨叶在动物细胞培养上的适用性,应用计算流体力学软件CFX综合比较在30 L搅拌槽中4种不同桨叶的流场、剪切率、Kolmogorov尺度和混合时间,并进行PIV实验验证。结果表明,在单层搅拌体系80 r/min转速下,象耳桨和螺旋桨性能能满足细胞培养要求,Rushton桨在细胞培养罐放大时可以考虑,45°四折叶桨能够适用于细胞培养,但效果不如象耳桨与螺旋桨,PIV实验验证了模拟结果可行性。     

基于离散元方法的差动自清洁混合器混合特性研究

采用离散元方法对LIST卧式差动双轴搅拌设备内高密度聚乙烯（PE?HD）填充碳酸钙复合材料的混合过程进行了仿真模拟，研究了不同加料速率及不同转速条件对该类自清洁混合器混合腔内物料充满度、物料停留时间分布及混合均匀程度的影响。结果表明，该类自清洁混合器的轴向输送能力主要由后续物料的推动作用实现，采用高速轴转速40 r/min，加料速率为10 kg/h的工艺参数可以获得最佳的混合均匀程度。     

在搅拌培养和静态培养中造血细胞亚群组成的分析

目的　分析转瓶和方瓶培养过程中造血细胞亚群组成的变化。方法　观察培养过程中脐血单个核细胞总细胞扩增倍数 ,CD34+ 细胞、CD33+ 细胞、CFU GM、CD4 1+ 细胞、CFU Mk和BFU E占总细胞的比例及其随培养时间的变化。结果　 14d的培养中 ,无论是用转瓶和方瓶 ,总细胞不断扩增 ,CD34+ 细胞含量在第 7天、CFU GM含量在第 10天、BFU E含量在第 5天达到最高 ,而后出现分化 ,转瓶和方瓶培养的CD34+ 细胞和CFU GM和BFU E含量差异无显著意义 ;CFU Mk则不同 ,其含量在转瓶培养第 7天时达到最高 ,而在方瓶第 10天达到最高 ,在转瓶中CFU Mk的含量一直低于方瓶培养 ;两种培养过程中CD33+ 细胞比例均在 5 0 %～ 70 %之间 ,而且差异无显著意义。转瓶培养中CD4 1+ 细胞含量到后期出现下降 ,而方瓶中则一直增加。结论　与静态培养环境相比 ,搅拌环境对干 祖细胞分化速度、粒 巨噬系祖细胞和红系祖细胞的分化没有明显影响 ,但不利于巨核系祖细胞的扩增 ,促进了其分化     

铁闪锌矿浮选精矿生物浸出

研究了氧化亚铁硫杆菌浸出铁闪锌矿浮选精矿的过程, 考察了正无菌、原菌种与驯化菌等条件下铁闪锌矿的浸出效果和矿浆浓度对矿物中有价金属浸出速率的影响. 摇瓶试验表明: pH值2.0、温度35 ℃、细菌接种量10%、矿浆浓度5%、矿石粒度<35.5μm(90%以上)和摇床转速160r&#8226;min^-1浸出条件下, 经过驯化的氧化亚铁硫杆菌能够显著地提高铁闪锌矿的溶解速率和浸出率;提高矿浆浓度导致铁闪锌矿中有价金属浸出率降低, 但单位时间内总的锌离子浸出量相应提高.     

黄孢原毛平革菌摇瓶体系产锰过氧化物酶优化研究

建立黄孢原毛平革菌液体反应体系,通过摇瓶液体培养试验,对黄孢原毛平革菌液体培养中温度、起始pH值、装液量、接种量、摇床转速等进行了对比研究。研究结果表明:温度为37℃、起始pH4.5、装液量250毫升/瓶、接种量1.3×106个孢子/毫升、转速120r/min为黄孢原毛平革菌摇瓶体系下产锰过氧化物酶的最适条件。     

摇床转速对VB12发酵的影响

通过设置不同摇床转速来调节通气量,以VB12脱氮假单孢菌发酵培养过程中的pH值、OD值、糖耗速率、菌体形态、发酵单位为指标,研究通气量对VB12脱氮假单孢菌生长的影响。结果表明：①通气量不仅影响菌丝生长而且影响菌体代谢产物VB12的合成。②可将脱氮假单孢菌发酵培养过程分为前中后3个阶段,对摇床转速进行调控,改变通气量,提高VB12发酵单位。     

Strikt anaerobe Batch‐Kultivierung von Eubacterium ramulus in einem neuartigen Einweg‐Beutelreaktorsystem

The first anaerobic cultivation of the gastrointestinal bacteria Eubacterium ramulus in a disposable bag reactor system is described. E. ramulus was cultivated in batches up to 10 L culture volume in a novel commercial disposable rocking motion bag reactor system for the first time. Optical densities about 5‐fold higher compared to previously used bottle cultivations could be obtained. Produced biomass per batch (10 L bag cultivation) yielded up 60 to 70 g wet cell mass. Comparative batch cultivation with the same volume in a common stirred tank reactor was performed. It showed results similar to the cultivation in the bag reactor system regarding optical density and wet cell mass.     

Optimization of Mixing and Mass Transfer in In-line Multi-Jet Ozone Contactors Using Computational Fluid Dynamics

Typical ozone mixing and mass transfer calculations are lumped approaches based on ideal operating conditions and can misrepresent behavior in real-life installations. This article models the effect of local hydrodynamics and mixing on the overall mass transfer of ozone into water with the aid of multiphase computational fluid dynamics (CFD). CFD models were validated with measured data from a pipeline ozone contactor installation which was optimized for more rapid, uniform mixing and mass transfer. Results emphasize the sensitivity of mixing quality to nozzle placement, size, orientation and spacing relative to main pipeline diameter and flows.     

Development of an efficient CFD-simulation method to optimize the structure parameters of an airlift sonobioreactor

A two-dimensional CFD model was developed for optimizing the structure design of an airlift sonobioreactor for hairy root culture, and a height to diameter ratio of 4 was found suitable for hairy root culture because both oxygen interphase mass transfer rate and liquid flow rate were high in the whole culture process. The installation position of ultrasound transducers was optimized with the help of CFD simulation, the ultrasound transducers set at three layers around the bioreactor wall gave the highest TKE value, turbulent dissipation rate and liquid flow rate among all installation positions tested, which is positive for the dissolved oxygen mass transfer into the center of hairy root clumps. The optimized structure of the airlift sonobioreactor provided great mass transfer performance and sharply reduced the gradient of dissolved oxygen in root domain. The detection results of dissolved oxygen concentration in hairy root clumps before and after ultrasound stimulation proved that ultrasound could enhance the mass transfer of dissolved oxygen into root clumps, which is an advantage for hairy root growth and secondary metabolite accumulation.     

CFD数值模拟在柠檬酸发酵罐搅拌系统设计过程中的应用

采用CFD(computational fluid dynamics)数值模拟对600 m3柠檬酸发酵罐搅拌系统设计方案进行分析,结合柠檬酸发酵工艺,综合考虑搅拌轴功率、流型、传质混合能力,提出了2种设计方案,并对其进行了数值模拟及传质混合能力分析,通过对比确定最优方案。     

新型转盘萃取塔研究开发与工业应用

采用激光多普勒测速仪(LDV)和计算流体力学(CFD)软件,对转盘萃取塔(RDC)内的单相流流场进行了测量和模拟。发现塔内存在沟流和级间的旋涡流动,级间返混严重,为此发明了一种装有级间转动挡板的新型转盘萃取塔(NRDC)。NRDC与传统的RDC的区别在于安装了设计独特的转动挡板。这些转动挡板安装在2个转盘之间,固定在转动轴上,并与固定环处于同一水平面。LDV测量和CFD模拟结果发现,NRDC可有效抑制沟流和级间旋涡流动。传质实验和流体力学表明,NRDC的传质效率比RDC高20%—40%,而液泛速度大致相当。成功地将NRDC用于引进RDC的扩能改造和新塔的设计中。     

大规模植物细胞培养生物反应器

讨论了植物细胞大规模培养的基本特性。根据分析比较了在植物细胞悬浮培养中通常使用的几种生物反应器,包括摇瓶,搅拌式反应器,气升式反应器,转瓶反应器以及带挡板的转瓶反应器,指出综合性能以气升式为最佳。此外还介绍了固定化植物细胞反应器以及生物膜反应器,讨论了大规模植物细胞培养反应器的选择原则。     

计算流体力学用于不同桨叶组合的ε-聚赖氨酸发酵

采用计算流体力学(CFD)数值模拟方法研究了2种不同桨叶组合(2个相同六直叶桨组合与上下档位分别为螺旋桨、六直叶桨组合)对5 L气液生物反应器的传质混合效果和剪切力的影响,并将这2种桨叶组合用于实验室规模ε-聚赖氨酸发酵。发酵实验结果表明,不同桨叶组合对微生物发酵特性产生了显著影响。相比1号罐,2号罐的菌体呼吸强度得到显著提高,最大菌体摄氧速率和CO2释放速率分别高出23%和32%;ε-聚赖氨酸合成强度提高了8%;同一时刻菌体干质量相差最大高出40%。     

INFLUENCE OF MIXING INTENSITY ON THE MASS TRANSFER COEFFICIENT ACROSS LIQUID-LIQUID INTERFACES

The influence of mixing intensity on the liquid-liquid mass transfer have been investigated using a binary system (water/n-butanol) in a modified stirred cell type contactor which overcomes the shortcomings associated with the previous contactors. It is observed that the mass transfer coefficient is affected by the degree of mixing intensity in both phases. The dependence of the aqueous and organic mass transfer coefficients on the mixing rate is about the same when both phases are agitated at the same speed and these coefficients become asymptotic values for the coefficients obtained at non identical agitation rate in both phases.     

填料塔基础理论研究新进展

规整填料塔具有效率高、压降低、放大效应不明显等优点,其成功应用有赖于对二相流动与传质的深入认识。文中综述了规整填料塔内的气液二相流动与分布、返混、气液二相在常压和高压下的传质特性、M arangon i效应以及计算流体力学(CFD)在规整填料塔中的应用等方面的国内外研究进展。填料塔内液体的分布与返混的研究较多,气相的流动分布与返混特性的研究较少,高压传质、M arangon i效应,特别是利用计算流体力学(CFD)模拟填料塔内的液体流动与传质等已逐渐成为研究的热点。     

Numerical study of mixing and thermal conduction of granular particles in rotating tumblers

A discrete element method (DEM) study is conducted to investigate the mixing and heat‐transfer characteristics of steel spherical particles under various rotation speeds and flow regimes of a rotating tumbler. The mixing degree, weighted temperature, temperature discrepancy at the mixing interface, temperature radial distribution, and information entropy are used to analyze the effect of mixing structure and evolution duration on the heat‐transfer characteristics. The results under the same revolution and the same evolution time are compared to show the effects of evolution time and mixing structure on thermal conduction. After a detailed analysis, the joint contribution of mixing degree and duration to granular heat transfer is explained, and the different approaches in static thermal conduction and dynamic mixing are shown. Moreover, a new method is proposed using the mean increase rate of temperature information entropy to determine the most effective operating condition for thermal conduction in granular particles. © 2013 American Institute of Chemical Engineers AIChE J, 59: 1906–1918, 2013