The treatment chamber is one of the crucial component of a PEF system, whose design is critical for successful treatment as its main function is to uniformly transfer the high voltage pulsed electric field to the food. Electrodes arranged in a co-field- or co-linear configuration are widely used due to their advantages fluid dynamics as well as high intrinsic resistance. However, the distribution of the electric field in the treatment zone is typically non uniform and the average field strength can be significantly different from the expected values derived from dividing the applied voltage by the electrode gap. In this work a total of 36 models of co-field chambers of different gap between electrodes (2-6 mm) and inner radius of the tube (1-3 mm) were developed by using Comsol MultiphysicsTM software. For each of these models, different setting of applied voltage (1-25 kV) were simulated for a model liquid food (aqueous solution with electrical conductivity of 2 mS/cm) and the values of the average electric field were computed. Results showed that homogeneity of the electric field distribution can be improved by decreasing the inner radius of the bore and/or increasing the electrode gap. The average electric field strength of the PEF treatment zone, was significantly lower than the expected values estimated assuming a parallel plate configuration. Finally, a relationship between the relative ratios of theoretical electric field strength to actual (average) electric field strength and the ratio of electrode radius and gap was also obtained.
Mathematical modelling of the electric field distribution in a co-field chamber of a PEF system
PATARO, GIANPIERO;LAMBERTI, PATRIZIA;FERRARI, Giovanna
2012-01-01
Abstract
The treatment chamber is one of the crucial component of a PEF system, whose design is critical for successful treatment as its main function is to uniformly transfer the high voltage pulsed electric field to the food. Electrodes arranged in a co-field- or co-linear configuration are widely used due to their advantages fluid dynamics as well as high intrinsic resistance. However, the distribution of the electric field in the treatment zone is typically non uniform and the average field strength can be significantly different from the expected values derived from dividing the applied voltage by the electrode gap. In this work a total of 36 models of co-field chambers of different gap between electrodes (2-6 mm) and inner radius of the tube (1-3 mm) were developed by using Comsol MultiphysicsTM software. For each of these models, different setting of applied voltage (1-25 kV) were simulated for a model liquid food (aqueous solution with electrical conductivity of 2 mS/cm) and the values of the average electric field were computed. Results showed that homogeneity of the electric field distribution can be improved by decreasing the inner radius of the bore and/or increasing the electrode gap. The average electric field strength of the PEF treatment zone, was significantly lower than the expected values estimated assuming a parallel plate configuration. Finally, a relationship between the relative ratios of theoretical electric field strength to actual (average) electric field strength and the ratio of electrode radius and gap was also obtained.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
