Susceptors in microwave cavity heating: Modeling and experimentation with a frozen pie

- Inclusion of a susceptor in coupled electrothermal modeling of heating of a frozen food.
- Experimental measurement of susceptor dielectric properties.
- Average conductive heat flux was initially four times higher with a susceptor.
- Uniformity of heating improved with a susceptor.
- Susceptor is more effective when combined with rotation.

Use of a susceptor (a metallized film attached to paperboard) in microwave heating can emulate conventional heating with benefits such as crisping food. This study develops a mechanistic understanding of this food-susceptor heating process. A coupled electromagnetic-thermal model was developed and validated for heating frozen food (a pie) in a package on a rotating turntable. Experimental measurements show that the susceptor has a moderately high dielectric constant but it also has a high dielectric loss, making it strongly microwave absorbing. Computed electric field, temperature, and energy absorption provided a comprehensive understanding. Presence of the susceptor increases the average conductive heat flux at the food-susceptor interface from ∼500 W/m2 to ∼2000 W/m2. By increasing the heat flux at the interface, a susceptor causes the food to absorb nearly three times as much energy initially, with the rate decreasing as the material thaws. The heating effectiveness of a susceptor increases when combined with rotation.