Combining microwave and jet-impingement in a oven prototype

Abstract The combination of microwaves exposure with the localized convection heating is seen as a practical solution to improve the uniformity and control of pure microwave heating of moist porous substrates. This effect is explored here, with an emphasis on the competition of such physical mechanisms. Simple experimental techniques have been adopted to determine the thermal response of a common biological substrate in a microwave (MW)/jet-impingement (JI) oven prototype (1 kW of nominal power), allowing for the local characterization of its electromagnetic and fluid dynamic behaviour. A rational approach is proposed by presenting a number of descriptors to help identify the MW/JI interrelationships that drive the substrate's local temperature rise, including the total process time (up to 1 min), the JI temperature (in the 60-100 °C range) and Reynolds number (in the 8000-15000 range)