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Droplet break-up in a rotor-stator mixer - evaluation of key parameters and their impact on droplet size

Jernberg, Josefina LU and Karlsson, Jonny LU (2016) KLT920 20161
Food Technology and Nutrition (M.Sc.)
Abstract
Liquid-liquid emulsions can be created using different mixing techniques and the equipment used for processing has a large impact on the final emulsion. Rotor-stator mixers are one of the most commonly used mixers today with multiple application areas. The droplet size is a key parameter during industrial mixing and emulsification, since it influences both the stability and quality of the product. The objective of this master thesis was to evaluate different key parameters that could have an impact on the drop size. Their impact was analyzed by studying the drop size distribution for the different experiments and the behavior of the droplet break-up was correlated to models suggested by theory.
Experiments were made in a batch... (More)
Liquid-liquid emulsions can be created using different mixing techniques and the equipment used for processing has a large impact on the final emulsion. Rotor-stator mixers are one of the most commonly used mixers today with multiple application areas. The droplet size is a key parameter during industrial mixing and emulsification, since it influences both the stability and quality of the product. The objective of this master thesis was to evaluate different key parameters that could have an impact on the drop size. Their impact was analyzed by studying the drop size distribution for the different experiments and the behavior of the droplet break-up was correlated to models suggested by theory.
Experiments were made in a batch rotor-stator mixer with a rotor diameter of 15 mm. They were conducted at a volume of 200 ml and rotor speeds ranging from 3 800 - 10 800 RPM. Viscosity models ranging from 1.00 to 25.3 mPa s were used to examine the viscosity impact and rapeseed oil was used as the disperse phase.

A conclusion from the experiments was that steady state was not reached. A typical dependence between drop size and number of passes was identified and as a result of this, two parameters of analysis were chosen to compare the results. Both the speed of the rotor and viscosity of the emulsion had a major impact on drop size. A higher tip speed and viscosity decreased the droplet size significantly. Both coalescence and viscosity impacts the drop size when increasing the oil fraction. The behavior of the droplet break-up was best described by the turbulent viscous regime due to the large impact of viscosity. (Less)
Popular Abstract (Swedish)
Viskositet och mixerhastighet,bland andra är två nyckelparametrar som påverkar droppuppbrottet i en rotor-stator mixer. En rotor-stator mixer är en av de vanligaste mixrarna som används i dagsläget då de bidrar till ett effektivt droppuppbrott med hjälp av höga skjuvkrafter.
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author
Jernberg, Josefina LU and Karlsson, Jonny LU
supervisor
organization
course
KLT920 20161
year
type
H2 - Master's Degree (Two Years)
subject
keywords
food engineering, livsmedelsteknik
language
English
id
8883735
date added to LUP
2016-06-28 10:36:01
date last changed
2016-06-28 10:36:01
@misc{8883735,
  abstract     = {Liquid-liquid emulsions can be created using different mixing techniques and the equipment used for processing has a large impact on the final emulsion. Rotor-stator mixers are one of the most commonly used mixers today with multiple application areas. The droplet size is a key parameter during industrial mixing and emulsification, since it influences both the stability and quality of the product. The objective of this master thesis was to evaluate different key parameters that could have an impact on the drop size. Their impact was analyzed by studying the drop size distribution for the different experiments and the behavior of the droplet break-up was correlated to models suggested by theory. 
Experiments were made in a batch rotor-stator mixer with a rotor diameter of 15 mm. They were conducted at a volume of 200 ml and rotor speeds ranging from 3 800 - 10 800 RPM. Viscosity models ranging from 1.00 to 25.3 mPa s were used to examine the viscosity impact and rapeseed oil was used as the disperse phase. 

A conclusion from the experiments was that steady state was not reached. A typical dependence between drop size and number of passes was identified and as a result of this, two parameters of analysis were chosen to compare the results. Both the speed of the rotor and viscosity of the emulsion had a major impact on drop size. A higher tip speed and viscosity decreased the droplet size significantly. Both coalescence and viscosity impacts the drop size when increasing the oil fraction. The behavior of the droplet break-up was best described by the turbulent viscous regime due to the large impact of viscosity.},
  author       = {Jernberg, Josefina and Karlsson, Jonny},
  keyword      = {food engineering,livsmedelsteknik},
  language     = {eng},
  note         = {Student Paper},
  title        = {Droplet break-up in a rotor-stator mixer - evaluation of key parameters and their impact on droplet size},
  year         = {2016},
}