Pressure losses in ducts

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Pressure losses in ducts
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Pressure losses in ducts
Example for Hsink

• Åke Mälhammar
• Frigus Primore
• malhammar.ake_at_wanadoo.fr

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Example
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ExcludeFriction negligible unless (channel
length)gt10x(channel diameter)Heat sink
accounted for by programFan
accounted for by program
Calculation on next page
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Example cont.
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CommentsInlet (Coeff0.3
a default assumption, in most cases lt0.5)Elbows
(Coeff1.1 could be up to 1.6 if
the velocity profile is mean, Acoutlet cross
section)Perforated plates (Coeff calculated by
http//www.frigprim.com/online/PerfPlate.html)Obs
tacle (Coeff as perforated plates.
Probably lower but better than nothing)Outlet
(Coeff1.0 only lower if there is
a diffuser with an opening angle lt20 deg)
Effective pressure loss coefficientCalculated
as (Item pressure loss coeffefficient)x(Aref/Ac)2