A finite element method based flow and heat transfer model of continuous flow microwave and ohmic combination heating for particulate foods

• A novel combination heater was designed for uniform heating of multiphase foods.
• COMSOL codes with FCM and ALE moving mesh techniques were implemented for modeling.
• Model predictions were consistent with experimental observations.

A 2D numerical model using COMSOL codes was developed to validate uniform heating of particulate foods in a continuous flow microwave (MW) and ohmic (OH) combination heater. The developed model was integrated with an electric field, electromagnetic field, incompressible laminar flow, forced-coupling method (FCM), heat transfer and arbitrary Langrangian–Eulerian (ALE) moving mesh technique. Three representative solid particles were simulated to experience hydrodynamic viscous drag and pressure forces resulting from their motions relative to fluid. The stress tensors of forces exerted on the particle surfaces were successfully formulated by use of the FCM module. The large deformation and movement of geometric mesh containing trajectories of particles inside the feeding tube were accurately predicted in an unsteady state. The simulated outlet temperatures of particulate foods had a good agreement with experimental data within the maximum prediction error of 4%.