A computational model for calculating temperature distributions in microwave food applications

By heating volumetrically, microwave processes have several advantages over conventional heating processes. The main advantage is the increase of process rates and thus improving the quality of microwave heated, dried, pasteurised or sterilised products. However, to ensure product safety and thus satisfy regulatory bodies, temperature distributions have to be as uniform as possible. A new simulation approach has been developed, based on a user-friendly interlace coupling two commercial software packages, to model time-dependent temperature profiles of arbitrarily shaped microwave treated products in three dimensions. Simulations have shown uneven temperature distributions when products were exposed to uncontrolled microwave applications. Using this model, hot and cold spots in the products may be simulated to test appropriate microwave treatment control strategies. A further development of this approach, being one-of-a-kind to date, describes a feedback-control loop in the simulation which helps optimising microwave processes by ensuring minimal time/temperature treatments and uniform temperature distributions. Thus microwave power pulse programs can be developed and tested in a model before being implemented in a real microwave system. Validation of the model was performed using non-invasive magnetic resonance imaging (MRI). Verification results showed that simulated data agrees well with the measured data in discrete locations (heating curves) as well as the temperature data throughout the samples. (C) 2007 Elsevier Ltd. All rights reserved.