In Eq. (14-83), QL = m3 liquid downflow/(h m weir length) and Af = fractional hole area based on active ("bubbling") area; for instance, Af = Ah/Aa.
The Kister and Haas method can also be applied to valve trays, but the additional approximations reduce its data prediction accuracy for valve trays to within ±20 percent. For valve trays, adaptations of Eqs. (14-81) to (14-84) are required:
4 x (area of opening of one fully open valve) wetted perimeter of opening of one fully open valve
= no. valves x (area of opening of one fully open valve)
active (bubbling) area
A correlation for valve tray entrainment flooding that has gained respect and popularity throughout the industry is the Glitsch "Equation 13" (Glitsch, Inc., Ballast Tray Design Manual, 6th ed., 1993;
available from Koch-Glitsch, Wichita, Kans.). This equation has been applied successfully for valve trays from different manufacturers, as well as for sieve trays with large fractional hole areas (12 to 15 percent). With tray spacings of 600 mm and higher, its flood prediction accuracy for valve trays has generally been within ±10 percent in the author's experience. The Glitsch correlation is
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