Numerical and experimental analysis of particle strain and breakage in turbulent dispersions

Maaß, Susanne; Wollny, Stefan; Sperling, Reinhard; Kraume, Matthias

doi:10.1016/j.cherd.2009.01.002

Cited by 23 publications

(16 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The MagLev centrifugal pumps revealed larger measured Sauter mean diameters, indicating lower mechanical stresses on emulsion drops compared with the peristaltic and 4-piston diaphragm pumps. In studies to date, inline endoscopy has been shown to be a robust and simple technique for reliable drop size measurement 1,6,[12][13][14][20][21] , which was also confirmed by this study. In comparison to alternative measurement techniques, such as the fiber optical FBR sensor, the FBRM and the 2D-ORM technique, the endoscope technique can be used as the standard method for obtaining precise data in liquid/liquid applications 12,14 .…”

Section: Discussionsupporting

confidence: 74%

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

Dittler

Dornfeld

Schöb

et al. 2015

JoVE

View full text Add to dashboard Cite

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors 1 . As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d 32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.

show abstract

Section: Discussionsupporting

confidence: 74%

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

Dittler

Dornfeld

Schöb

et al. 2015

JoVE

View full text Add to dashboard Cite

show abstract

“…The findings from the single drop investigations were used to simulate experiments in a lab scale stirred tank DN 150 (see section 2.1 for details) with the same physical system toluene/water at a disperse phase fraction of = 10%. In these experiments the drops are about one order of magnitude smaller (200 -600 µm) and the absolute flow velocities within the stirred tank are in the order of ≈ 1 m/s (Maaß et al, 2009). But for coalescence the relative velocity of droplets flowing within the continuous flow is important and can be estimated by Equation (8).…”

Section: Transfer To Droplet Swarmsmentioning

confidence: 95%

From single drop coalescence to droplet swarms – Scale-up considering the influence of collision velocity and drop size on coalescence probability

Kamp

Kraume

2016

Chemical Engineering Science

View full text Add to dashboard Cite

Coalescence modelling in liquid/liquid dispersions is a challenging task and field of investigations up to now, which becomes apparent when comparing the various existent models with their different and partly even contradictive implementation of influencing factors. In this work, systematic investigations of single drop coalescence were used to compare and validate different coalescence efficiency models regarding the important influencing parameters relative collision velocity and drop size. The impact of these parameters could be analysed independently from each other for the first time and used to identify the best modelling approach. Moreover, the numerical parameter of the coalescence efficiency model could be obtained based on single drop experiments. Using this determined parameter the simulation of drop size distributions within a lab scale stirred vessel was possible. The presented method offers the possibility of independent parameter estimation for population balance equation simulations based on single drop experiments. The application of this systematic approach allows the separate validation of submodels and reliable parameter determination by small scale investigations. On this basis a sound scaleup is possible using population balance equation simulations. Postprint: Kamp, J.;, From single drop coalescence to droplet swarms -Scale-up considering the influence of collision velocity and drop size on coalescence probability, Chemical Engineering Science, 156, 162-177, https://doi.org/10.1016/j.ces.2016.08.028 2 the drop breakage (Maaß and Kraume, 2012), this work focusses on drop coalescence and its modelling in PBE. Drop CoalescenceCoalescence describes the confluence of two disperse droplets or a drop with the corresponding continuous phase. Before coalescence between two droplets occurs, the interfaces approach each other and a thin film of surrounding continuous phase has to drain between the interfaces. At a certain critical distance the continuous phase film ruptures and the drops confluence. However, a collision of droplets does not end in coalescence necessarily, but may also results in a repulsion or agglomeration of the droplets. The probability of coalescence after droplet collision is described by the coalescence efficiency in PBE. The coalescence efficiency is influenced by numerous factors especially surface active components in already small amounts (Kamp et al., 2016b). Due to the involved complex interactions in distances of several orders of magnitude, numerous modelling approaches can be found in literature (Liao and Lucas, 2010) which implement influencing factors differently and in parts even contradictorily (Kamp et al., 2016b;Kopriwa et al., 2012). Postprint: Kamp, J.;, From single drop coalescence to droplet swarms -Scale-up considering the influence of collision velocity and drop size on coalescence probability, Chemical Engineering Science, 156, 162-177, https://doi.org/10.1016Science, 156, 162-177, https://doi.org/10. /j.ces.2016.08.028 3 Population Balance Equation (PBE...

show abstract

“…This research utilized two main set‐ups: a single‐drop breakage cell 25 and an agitated vessel at lab scale (see below) 26. Both have been used in previous studies.…”

Section: Methodsmentioning

confidence: 99%

“…The mother drop sizes were set between 500 and 3500 μm. A highly accurate dosing pump produced mother drops with an SD of the diameter of less than 0.003 mm 25.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of particle strain in stirred bioreactors by drop breakage investigations

Maaß

Buscher

Hermann

et al. 2011

Biotechnology Journal

View full text Add to dashboard Cite

Understanding of particle strain and drop breakage is relevant for various technical applications. To analyze it, single drop experiments in a breakage cell and evolving drop size distributions in an agitated system are studied. The mechanisms for particle strain and drop breakage are assumed to be comparable for the investigated turbulent flow regime. The agitation process is simulated using a population balance model. This model provides transient prediction capacities at different scales and can be used for scale-up/down projects. The number and the size distributions of daughter fragments for single drops have been studied. The results clearly support the assumption of binary breakage. The most common assumption of a Gaussian distribution for the daughter drop size distribution could not be supported. The evolution of a breakage-dominated toluene/water system was then simulated using different daughter drop size distributions from literature. The computational results were compared with experimental values. All simulations were able to predict the transient Sauter mean diameter excellently but varied strongly in the results on the shape of the distribution. In agreement with the experimental single drop results, the use of a bimodal or a very broad bell-shaped distribution of the daughter drops is proposed for the simulations. Although these results were obtained in a particular vessel for a specific phase system, it can be applied to simulate transient multiphase systems at different scales. We would expect that the general trends observed in this study are comparable to various applications in multiphase bioreactors.

show abstract

Numerical and experimental analysis of particle strain and breakage in turbulent dispersions

Cited by 23 publications

References 16 publications

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

From single drop coalescence to droplet swarms – Scale-up considering the influence of collision velocity and drop size on coalescence probability

Analysis of particle strain in stirred bioreactors by drop breakage investigations

Contact Info

Product

Resources

About