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-   -   help in pressure drop calculation in fluent (https://www.cfd-online.com/Forums/fluent/103314-help-pressure-drop-calculation-fluent.html)

 sinaupdate June 17, 2012 07:32

help in pressure drop calculation in fluent

hi everyone
i want to calculate the pressure drop of fluid along a pipe with anuular section ,in result i see that the pressure drop that fluent give me is 200 pa less than exact pressure drop that it must be..

what is the reason for that??
lenght = 12 ft D_out = 2.91 in D_in=1.8 in mesh 2,600,000
out let boundary = 0 pressure
inlet boundary= velocity inlet
fluid =water

for water inlet with velocity INLET 1.58 i receive 1100 pa/m pressure drop but it must be more.
tnx for any help

 ghost82 June 17, 2012 08:39

Have you set roughness in wall boundaries?

 sinaupdate June 17, 2012 16:52

hi
yes roughness constant as a default is 0.5
i dont know when i do it by one liquid, result is little lower and when i use liquid-solid, pressure drop it twice the exact result !!

:(

 Omish July 10, 2016 05:56

Quote:
 Originally Posted by sinaupdate (Post 366903) hi yes roughness constant as a default is 0.5 i dont know when i do it by one liquid, result is little lower and when i use liquid-solid, pressure drop it twice the exact result !! :(
Hi