COMSOL Multiphysics model for continuous flow microwave heating of liquids

A numerical model was developed to simulate temperature profiles in Newtonian as well as non-Newtonian fluids during continuous flow microwave heating by iterative coupling of electromagnetism, fluid flow and heat transport in COMSOL Multiphysics. The model was validated by using extensive experimental data for carboxymethyl cellulose solution and tap water flowing at two different flow rates (1 and 2 l/m) through a 915 MHz continuous flow microwave system at 4 kW of power. The electromagnetic power generation (18–20% error) and average numerical temperature were in fairly good agreement with the average experimental temperatures for carboxymethyl cellulose (R2 = 0.89 at 1 l/m and R2 = 0.91 at 2 l/m) and tap water (R2 = 0.90 at 1 l/m and R2 = 0.81 at 2 l/m).