What are the aeration design guidelines for proper air flow velocity and air flow rates?
Aeration ducts should have sufficient cross section area (length x width, or diameter) to provide velocity through the initial part of the transition duct and along the perforated duct of about 1,800-2,000 ft/min or about 30-35 ft/sec. This in-duct velocity minimizes duct air friction losses to an acceptable level. The total duct perforated surface area (area exposed to the grain) should provide air movement through the perforated area (entrance or exit air velocity) of about 30-45 ft/min. A 10,000 bu steel bin in the southern states should have a minimum design airflow rate of about 0.2 cfm/bu and a preferred rate of 0.3 cfm/bu, so the fan should deliver at least 2,000 cfm, but preferably 2,500-3,000 cfm. To match the minimum recommended air volume of 2,000 cfm, the transition duct and aeration duct should have a minimum cross-section area of 1.0 sq ft, which would provide an entry duct velocity of 2,000 ft3/min/1.0 sq ft = 2,000 ft/min. To provide 30 ft/min air velocity through the p
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