7.1 Definition of tray areas
The definition of tray areas and its nomenclature illustrated in Figures 7.2 &7.3 are followed throughout the design procedure.
Total tower cross-section area (AT): The empty tower inside cross-sectional area without trays or downspouts.
Net area (AN ) (also called free area): The total tower crosssectional area (AT) minus the area at the top of the downcomer (ADT). The net area symbolizes the smallest area available for vapor flow in the inter-tray spacing.
Bubbling area or active area (AA): The total tower cross-sectional area minus sum of the downcomer top area (ADT) and downcomer seal area (ADB) and any other nonperforated areas on the tray. The bubbling area represents the area available for vapor flow just above the tray floor.
Hole area (Ah): The total area of the perforations on the tray. The hole area is the smallest area available for vapor/gas passage.
Figure 7.2. Schematic of a tray operating in the froth regime ( [2] page 14-28 ).
Figure 7.3. Typical cross-flow plate (sieve) ( [3] page 557 ).