Mathematical modelling and performance analysis of airflow distribution systems inside convection hot-air dryers

Abstract

As a section on improving the energy efficiency and thermal efficiency of convection dryers, a different airflow distribution system in the convection dryer was established. The grape drying experiment was investigated by applying three types of distribution air inside a convection hot-air dryer. The vertical system (VS) in which hot air passes vertically through the tray of samples. However, the air was delivered parallel to the sample tray in two horizontal systems (HS) Types (I, II). The investigations were approved with the different air-drying temperatures of 40, 50, and 60 °C at different velocity 1.0, 1.5, and 2.0 m/s. The drying time in the horizontal dryer compared to the vertical system was significantly less. The data analysis showed that horizontal energy consumption with a type (II) dryer was low while the energy consumption was high under the vertical dryer. Moreover, applying the horizontal Type (II) for grapes drying had numerous improvements above the conventional vertical system, such as shorter processing times, less overall energy utilisation, and higher dryer thermal efficiency. According to the results, after fitting the experimental data with eleven drying kinetics models and comparing the results in terms of the root mean square error (RMSE), the reduced chi-square (χ2), and the correlation coefficient (R2), it was obtained that logarithmic model can give practically accurate evaluations of the drying curve for grapes drying in different convection dryers.

Keywords

• Mathematical modeling
• Grapes
• Convective drying
• Distribution air
• Kinetics