Pulsed electric field (PEF) processing is a nonthermal treatment that uses high voltage electric pulses (HVEP) for many operations in food and bioengineering, including improvement of protein digestibility, potato processing, microalgae processing, exposure of biological cells, fruit processing, and meat preservation. The processing medium, placed between or passing through two electrodes, are affected by the HVEP of a few microseconds. There have been proposed several designs of PEF treatment chamber such as parallel, co-axial and co-linear configuration. Of all the configurations, the co-linear design is regarded as the most effective. Although this technology has already been introduced to industrial application such as food preservation, the detailed mechanisms of HVEP action on different processing media still remain imperfect.
To clarify the beneficial effect of HVEP and find the proper design of treatment chamber for different treatment objects, more reliable and optimized modeling on the electric field of PEF treatment chamber should be conducted because its measurement is difficult or impossible to perform. Many new data on the electric field of PEF treatment chamber have been presented but the simulation results are not identical with each other. The origin of different results in the literature is likely related to the difference in the simulation conditions, which might cause ambiguity in clarifying the mechanism of PEF treatment and designing the device.
Ham Kum Hae, a post-graduate student at the Faculty of Physical Engineering, has constructed a model to simulate the electric field in a PEF treatment chamber and verify the advantage of a new type of treatment chamber by lattice Boltzmann method.
First, she developed a lattice Boltzmann model (LBM) to describe the electric field distribution in co-linear PEF processing. Based on the assumption that PEF does not cause a time varying magnetic field, she carried out a simulation by using the charge conservation equation. For a two-dimensional LBM, she specified a macroscopic boundary condition for electric potential at high voltage and ground electrodes, and a bounce-back boundary condition for electric potential at the insulator. Next, she suggested a new type of treatment chamber with “holo-elliptical” geometry where the uniformity of electric field was remarkably improved.
For more details, you can refer to her paper “Lattice Boltzmann Simulation of Electric Field in Co-Linear Pulsed Electric Field (PEF) Treatment Chamber” in “Bulletin of the Lebedev Physics Institute” (SCI).
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