Research of the Effect of Different Circular Moist Object Geometries for Air Jet Impingement Drying on Heat and Mass Transfer

Drying is one of the most used methods for long-term storage by removing water from food. The physical and chemical changes occurring during storage are minimal due to the reduction of considerable amount of water and microbial activity of the food. In the present study, the effect of the two different new moist object geometries with whole and reverse semi-circular on the heat and mass transfer enhancement of drying with air jet was numerically examined. The drying jet was a laminar and 2D jet stationed at a constant jet distance (H) from the moist object. The diameter of the moist object, jet distance from the moist object and jet initial height were fixed for all cases. Streamlines and isotherms were acquired around the objects for different jet Reynolds numbers. A finite volume method was used to solve the governing equations by using ANSYS Fluent 17.0 software program. Calculations were carried out for different Reynolds numbers, namely, Re=100, 200 and 300. It was found good agreement with experimental and numerical data available in the literature. The results showed that the geometry of whole circular moist object had better performance of heat and mass transfer than that of the reverse semi-circular moist object geometry. In addition, increasing Reynolds number showed a positive effect on heat and mass transfer. Locally, jet drying was found to be most effective near the stagnation point on the leading side of the objects