Browsing Δημοσιεύσεις σε συνέδρια by Subject "Airflow"
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- ItemOpen AccessAir flow characteristics in an industrial wood pallet drying kiln
Τμήμα Μηχανολόγων και Αεροναυπηγών Μηχαν. (Δημοσ. Π.Π. σε συνέδρια)(2013-07-30) Tzempelikos, Dimitrios; Filios, Andronikos; Margaris, Dionissios; Τζεμπελίκος, Δημήτριος; Φιλιός, Ανδρόνικος; Μάργαρης, ΔιονύσιοςThe improvement and optimization of air-distribution systems in drying kilns contributes to the preservation of the quality, safety and shelf life of perishable products. The present study reports on the numerical solution of airflow within a two dimensional drying kiln enclosure loaded with wooden pallets. The performance of air flow field is examined with and without supply of wooden pallets. Different arrangements of the supplied wooden pallets are investigated as well as the use of a screen in order to improve the airflow field. The steady state RANS equations that formulate the flow problem are solved along with a turbulence model that is the standard k-ε or the rng k-ε. The effect of the turbulence modeling is distinguished through direct comparisons of the derived airflow patterns. The results obtained show the presence of stagnant zones inside the pallets columns and above of them and the presence of recirculation regions in different zones of the drying kiln with the two turbulence models.
- ItemOpen AccessAirflow patterns in a laboratory batch-type, tray air dryer
Τμήμα Μηχανολόγων και Αεροναυπηγών Μηχαν. (Δημοσ. Π.Π. σε συνέδρια)(2013-07-30) Tzempelikos, Dimitrios; Vouros, Alexandros; Bardakas, Achilleas; Filios, Andronikos; Margaris, Dionissios; Τζεμπελίκος, Δημήτριος; Βούρος, Αλέξανδρος; Μπαρδάκας, Αχιλλέας; Φιλιός, Ανδρόνικος; Μάργαρης, ΔιονύσιοςThe batch-type dryer is one of the most popular equipment for fruit drying. However, the optimization of the air distribution inside the drying chamber remains a very important issue, due to its strong impact on efficient drying and uniformity of moisture content of products. A new scale laboratory batch-type, tray air dryer has been designed, constructed and evaluated for drying several horticultural and agricultural products. The flow field inside the dryer is studied through computational fluid dynamics (CFD). A three-dimensional model for laboratory dryer has been created and the steady state incompressible, Reynolds-Averaged Navier-Stokes (RANS) equations that formulate the flow problem are solved, incorporating standard and RNG k-ε turbulence models. The simulations are conducted for testing chamber average velocity of 2,9 m/s at ambient temperature. The CFD models are evaluated by comparing airflow patterns and velocity distributions to measured data. Numerical simulations and measurements convince that the new scale laboratory batch-type dryer is able to produce a sufficiently uniform air distribution throughout the testing chamber of the dryer.
- ItemOpen AccessIndustrial drying of wooden pallets - CFD analysis of air flow
Τμήμα Μηχανολόγων και Αεροναυπηγών Μηχαν. (Δημοσ. Π.Π. σε συνέδρια)(2013-07-30) Ghiaus, Adrian; Filios, Andronikos; Margaris, Dionissios; Tzempelikos, Dimitrios; Φιλιός, Ανδρόνικος; Μάργαρης, Διονύσιος; Τζεμπελίκος, ΔημήτριοςThis paper presents the results of the airflow 2D numerical simulation inside an industrial unit designed for drying of wooden pallets. The airflow field profile was examined in different operation conditions by plotting velocity vector distribution, path lines and pressure contours for both loaded with the wooden pallets and unloaded drying room. The analysis of the obtained results shows the presence of stagnation zones between and above the pallet columns and recirculation regions in different zones of the drying room. Further work will focus on validation of the predicted CFD results by means of local measurements that will be taken on a full scale dryer.