Numerical study of the ohmic heating process applied to different food particles

Abstract

In the present work, some aspects related to the ohmic heating (OH) technology are investigated using the Ansys Fluent. The aims of this study are: (i) implementing a mathematical and numerical model capable of reproducing the OH process, (ii) evaluating the influence of the electrical voltage over the transient heating, (iii) investigating the importance of the ohmic cell diameter and (iv) electrodes diameter regarding the heating generated. The computational domain represents a cylindrical ohmic cell used to heat pieces of carrot, meat and potato within an aqueous NaCl solution. Results about the role of the electrical voltage show that the most intense heating was obtained with the highest voltage tested. While it is needed about 2 min to the temperature of the carrot particle reach about 335 K using 50 V, approximately 9 min (a time 450 % greater) are necessary to the particle reach the same temperature using 20 V. Temperature differences for a same particle are also observed when the importance of the electrodes diameter is analyzed. In this case, the highest difference occurs for the meat particle (11.94 K at 138 s), thus it can be stated that the heating generated was influenced by the electrode size.