CFD-assisted dispersing flow optimization in a novel ultra-high-pressure device
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Date
2023-03-08Type
- Other Conference Item
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Abstract
The basis for emulsification with high-pressure homogenizers (HPHs) lies within the energy input and flow type. Droplet disruption, coalescence and stabilization by emulsifiers can be modified by altering the dispersing flow profiles [1, 2]. Mostly, small droplet sizes and narrow droplet size distributions are desired to improve bioavailability of functional compounds or the possibility of texture modifications [3]. The resulting droplet size depends on the interplay between droplet fragmentation and coalescence in the dispersing flow chamber (DFC) [4].
The main challenge addressed in this work was to optimize droplet breakup and reduce recoalescence within the DFC by removing domains of back flow and recirculation and include supportive cavitation management.
This was achieved by tayloring the DFC to an adaptive streamline shape design with computational fluid dynamics simulations using OpenFOAM Large-Eddy Simulation. Based on this, such novel DFC+ was manufactured and operated with a minimally pulsating ultra-high-pressure intensifier pump enabling the application of up to 600 MPa of static pressure. Flow characterization revealed that the predominant flow type is highly turbulent with Renozzle = 55000 at 300 MPa. Turbulent viscous and inertial flow domains were identified using the dissipation rate criterion of turbulent kinetic energy. Smallest droplet sizes were obtained with the novel DFC+ prototype and applied pressure between 200-300 MPa, a nozzle diameter of 80 µm and back pressure of 18 MPa. Compared to the industry standard Microfluidizer Y-type HC, droplet sizes obtained with the streamline the DFC+ at the maximal comparable pressure were up to 40 % smaller when processing high-viscosity-ratio emulsions of λ=100 to λ=1000, respectively. Using the DFC+, also stronger cell disruption of S. cerevisiae and A. platensis and higher nitrogen extraction from C. vulgaris was achieved. Show more
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unpublishedEvent
Subject
High pressure dispersingOrganisational unit
03345 - Windhab, Erich Josef (emeritus) / Windhab, Erich Josef (emeritus)
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