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Discharge coefficients for openings in metal or plywood walls of recirculation ducts

Authors: R. Patsula, J.J.R. Feddes and J.J- Leonard
Description: The effect of recirculation duct air outlet materials on the coefficient of discharge values (Cd) were studied. Opening diameters investigated were 50-mm sheet metal, and 50-mm and 25-mm plywood. Static pressures, duct velocities, and opening exit velocities were measured along a length of 5-m rectangular plywood duct. Values of Cd were calculated directly from the measured static pressure and duct velocity values. The mean Cd values for 50-mm metal, 50-mm plywood, and 25-mm plywood openings were 0.70,0.72, and0.71,respectively forexitvelocities of 5 m/s. For each type of opening, Cd values decreasedby 0.0133 per metreof duct length.The meanstatic pressureand duct airspeedwas 27Paand2 m/s,respectively. Aperture ratiowas0.785. Opening exit velocities were approximately 5 m/s.The increasein static pressure and decrease in the Cd value along the length of the rectangular duct resulted in a very uniformdistribution of airflowalong the duct.
Citation: R. Patsula, J.J.R. Feddes and J.J- Leonard 1992. DISCHARGE COEFFICIENTS FOROPENINGS IN METAL OR PLYWOODWALLS
OF RECIRCULATION DUCTS. Canadian Agricultural Engineering 34(4):359-363.
Volume: 34
Issue: 3
Publisher: Canadian Society for Bioengineering
Date: 1992
Type: Text.Article
Format: PDF
Coverage: Canada
Language 1: en
Rights: Canadian Society for Bioengineering
Located in: Volume 34 (1992)