Application of Numerical Simulation Techniques for Modeling Pulsed Electric Field Processing

Development of a Continuous Pulsed Electric Field (PEF) Vortex-Flow Chamber for Improved Treatment Homogeneity Based on Hydrodynamic Optimization

“…The set of parameters represents typical conditions for a pilot-scale PEF treatment and was therefore chosen as a test case for the comparison of the treatment chamber characteristics. The computed flow and temperature patterns in the co-linear chamber agree to the descriptions in the literature (Jaeger et al, 2009;Woelken et al, 2017) and are characterized by parallel streamlines and the formation of a liquid jet behind the treatment zones. This flow pattern creates a recirculation zone behind the insulators, where local temperature maxima can be found.…”

“…In this regard, all material properties except from the electrical conductivity were assumed to be constant and independent from temperature. In case of the electrical conductivity, a linear relationship with respect to the temperature was assumed (Woelken et al, 2017), according to experimental measurements. Consequently, the electric and temperature fields were coupled to each other.…”

“…Previously published studies on improvement of treatment homogeneity during PEF processing optimized the inner insulator geometry (Buckow et al, 2011;Meneses et al, 2011b;Woelken et al, 2017), applied electrode cooling (Meneses et al, 2011a), or implemented a static mixer in the treatment chamber (Jaeger et al, 2009). The treatment chambers investigated were already equipped with an optimized insulator geometry, as described by Meneses et al (2011b).…”

“…However, due to this design, the electric field is not equally distributed within the chamber. In fact, highest current densities are present at the inner walls of the chamber (Jaeger et al, 2009;Reineke et al, 2015;Woelken et al, 2017). Moreover, as treatments usually operate under laminar flow conditions, this also corresponds to the position with the lowest flow velocity, therefore leading to local electric field and temperature peaks, accompanied by possible negative effects on heatsensitive compounds of the product to be treated.…”