MEASURING AIRFLOW DISTRIBUTION IN PEANUT DRYING TRAILERS

Abstract

A method to measure airflow distribution exhausted from a filled peanut drying trailer was developed. Six 6.4-m peanut drying wagons were loaded with dry farmer stock peanuts at a local peanut processing facility. Three wagons had floors with 23% O.A. and three had 40% O.A. Peanuts were leveled on each trailer and peanut depth ranged from 114 to 130 cm. A 76-cm diameter, 1750 rpm, four-blade vane axial dryer with a 91-cm long straightening inlet transition was connected to each peanut drying trailer. The rated airflow capacity of the dryer was approximately 510 m3 min-1 at 124 Pa. Total airflow was measured using a pitot tube traverse across the inlet transition. Static pressure was measured in the wagon plenum using a U-tube manometer. The top of the trailer was divided into 40 sections using a 5 8 cell grid. The airflow through each grid cell was measured using a vane anemometer mounted on a conical transition placed in the center of each grid cell. No significant differences in static pressure, total airflow, or airflow distribution due to the percent O.A. of the perforated drying floor were detected. The average static pressure observed for wagons with the 23 and 40% O.A. was identical at 120 Pa. Total airflow measured at the fan inlet averaged 367 m3 min-1 for the 40% O.A. trailers compared to 366 m3 min-1 for trailers with 23% O.A. The total of the air flow measured as it exhausted from the peanuts was 63% of the flow measured using the pitot tube at the fan inlet.