Modeling of ohmic heating patterns of multiphase food products using computational fluid dynamics codes

Modeling of the thermal behavior of multiphase food products with various electrical conductivities under ohmic heating has been a challenge. Distortion of electric field due to heterogeneous food properties and electrical conductivity distribution should be taken into consideration for accurate prediction of the thermal performance of ohmic heaters. The objective of this study was to model ohmic heating pattern of solid–liquid food complex that contain three different solid particles with substantially different electrical conductivities and 3% NaCl solution. The solid food samples used in this experiment were potato, meat, and carrot, which are less conductive than carrier medium. The transient heating patterns of each solid food and carrier medium were simulated using computational fluid dynamics (CFD) codes with user defined functions (UDFs) for electric field equations. The predicted temperature values were in good agreement with the experimental data with the maximum prediction error of 6 °C. Hot spots existed on the continuous phase in zones perpendicular to the solid cubes and cold spots were in between the particles where the current density lacks. CFD model prediction of detailed thermal profiles of multiphase food mixtures under the static ohmic heating will assist in designing of a continuous flow ohmic heater with pursuit of heating uniformity, furthermore, ensuring food safety and quality.