Refrigeration, air-conditioning and cooling technology - 2007.pdf

PLH_KKK_86_103.QXP 25.05.2007 10:24 Uhr Seite 88APPENDIXTables and guide valuesLoss coefficientRdBent elbows 15° 30° 45° 60° 90°Surface Surface Surface Surface Surfacesmooth rough smooth rough smooth rough smooth rough smooth roughζ for R = 0 0.07 0.10 0.14 0.20 0.25 0.35 0.50 0.70 1.15 1.30ζ for R = d 0.03 – 0.0 - – 0.14 0.34 0.19 0.46 0.21 0.51ζ for R = 2 d 0.03 – 0.06 – 0.09 0.19 0.12 0.26 0.14 0.30ζ for R 5 d 0.03 – 0.06 – 0.08 0.16 0.10 0.20 0.10 0.20Welded kneesNumber of circumferential weld seams– – – – 2 – 3 – 3 –ζ – – – – 0.15 – 0.20 – 0.25 –Qa/Q = 0.2 0.4 0.6 0.8 1ζ a = - 0.4 0.08 0.47 0.72 0.91Q dQζ d = - 0.17 0.30 0.41 0.51 –Q aQ dQ aQζ a = 0.88 0.89 0.95 1.10 1.28ζ d = -0.88 -0.05 0.07 0.21 –Q dQ aQ45°ζ a = -0.38 0 0.22 0.37 0.37ζ d = 0.17 0.19 0.09 -0.17 –Q45°Q dζ a = 0.68 0.50 0.38 0.35 0.48ζ d = -0.06 -0.04 0.07 0.20 –Q aThe ζ-value of the simple 90° elbow is not to bedoubled when putting several elbows togetheras follows, but is only to be multiplied by the respectivelyspecified factor in order to get theloss of the multiple elbow.1.4 1.6 1.888 Subject to change without prior notice 02/2007 WILO AG