| Περίληψη: | Aiming to overcome the lack of experimental data in the open literature and the necessity to validate numerical models which are an essential tool for optimization and increase the efficiency of the drying process, a laboratory convective (LC) dryer has been designed, constructed and equipped with an integrated measurement and control instrumentation. The main sections of the LC dryer, which can be arranged for operation in a closed or open circuit mode through manually controlled dumpers, are the vertical flow drying chamber, the heat exchanger, the boiler and the fan - motor with smooth speed control unit. The experimental facility is under operation for testing and monitoring the hydration of horticultural and agricultural products. The current paper outlines the methodology applied for the design and optimization of the LC dryer which it has been achieved through the analysis of the flow field by means of computational fluid dynamics (CFD). The prediction of the three – dimensional flow problem is accomplished through the solution of the steady-state incompressible, Reynolds-Averaged Navier-Stokes (RANS) equations with the incorporation of standard turbulence model. The measurement and control instrumentation with the inclusion of the innovative, pc-controlled, 3d traverse system that serves detailed surveys of temperature and velocity inside the drying chamber, are discussed. The performance test and evaluation of the LC dryer is conducted using quince as a test material at an average temperature of 60oC and air of 2 m/sec into the drying chamber.
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