Numerical study of treatment chambers for single and multi‐stage pulsed electric field systems

Abstract Pulsed electric field (PEF) systems should be designed to be microbiologically and energy efficient for industrial applications applied to treatment of different types of liquid foods. A thorough numerical model for the design of PEF systems is presented. It takes into account two combined approaches, a field evaluation based on an electric‐thermal‐fluid dynamic analysis and a design of numerical experiment considering as variables the applied high voltage and the internal electrode radius of a coaxial geometry. Then, the survival ratio and the specific energy are solved as conflicting objectives for the PEF design, using the treatment time and pulse frequency from the coupled analysis. The formulation is applied for grape and orange juices with E. coli for single and multiple stages systems. The simulations with multiple stages for the grape juice showed that it is possible to reach a microbial inactivation of 3.1 (log10 scale of survival rate) with a specific energy of about 450kJ/kg lower in relation to a two stage system. It means an energy reduction of 92, 421kJ/h for a treatment system with a capacity of 163 L/h.