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1. Pressure losses in ducts. Pressure losses in ducts. Example for Hsink. Åke Mälhammar Frigus Primore malhammar.ake@wanadoo.fr. Example . 2. Perf plate 2. Fan. Heat sink. Obstacle. Elbow 3. Elbow 2. A c =80 cm 2. Perforated plate 1. A ref =100 cm 2. A c =100 cm 2. A c =30cm 2.
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1 Pressure losses in ducts Pressure losses in ducts Example for Hsink Åke Mälhammar Frigus Primore malhammar.ake@wanadoo.fr
Example 2 Perf plate 2 Fan Heat sink Obstacle Elbow 3 Elbow 2 Ac=80 cm2 Perforated plate 1 Aref=100 cm2 Ac=100 cm2 Ac=30cm2 Elbow 1 Ac=75 cm2 Ac=80 cm2 Exclude:Friction [negligible unless (channel length)>10x(channel diameter)]Heat sink [accounted for by program]Fan [accounted for by program] Calculation on next page
Example cont. 3 Comments:Inlet (Coeff=0.3 a default assumption, in most cases <0.5)Elbows (Coeff=1.1 could be up to 1.6 if the velocity profile is mean, Ac=outlet cross section)Perforated plates (Coeff calculated by http://www.frigprim.x10.mx/online/PerfPlate.html)Obstacle (Coeff as perforated plates. Probably lower but better than nothing)Outlet (Coeff=1.0 only lower if there is a diffuser with an opening angle <20 deg) Effective pressure loss coefficient:Calculated as (Item pressure loss coeffefficient)x(Aref/Ac)2