Preliminary Investigation of the Flow Distribution in an Innovative Intermittent Convective microwave Dryer (IMCD)

Abstract

Intermittent Microwave Convection Drying (IMCD) is an innovative concept that has the potential to reduce drying time and improve both energy efficiency and product quality. However very few studies on flow or temperature distributions on IMCD can be found in the literature. In this study, an innovative U shaped continuous flow IMCD has been proposed. In order to take full advantage of the IMCD technology, a uniform airflow distribution in the drying chamber is critical. Uneven airflow in the drying chamber significantly deteriorate the food quality and energy efficiency and increase the drying time. This research investigates the flow distribution in the proposed U shaped IMCD using computational fluid dynamics (CFD). Effects of varying inlet air velocity on the airflow distribution were investigated. The geometry, mesh and turbulence model were kept constant throughout the investigation. COMSOL Multiphysics software alongside a SST k-ω turbulence model was utilised. The investigation revealed that the distribution of the U shaped geometry minimises the 'dead flow' regions compared to rectangular shaped geometry. However, two small 'dead zones' were still found in U shaped geometry. This study further investigates how these dead zones can be minimised by changing the location of inlets and outlets. © 2017 The Authors.