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Unread 09-20-2005, 06:24 PM   #80
bobo5195
Cooling Savant
 
Join Date: Aug 2005
Location: uk
Posts: 400
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im talking about straight pipe entry reynolds here. V beign average pipe velocity and L being diameter,so nothing too fancy.

Are you talking about turbulators in the nozzles as i thought they were just drilled holes. Im fairly sure that the nozzle length is long enough that the flow in them is fully developed lamina flow even if the entry flow is turblent. End turbulators are going to effect the flow (for good from what ive seen) but on a 0.45mm hole getting them right is going to be tricky.

cengel and boles (my heat transfer lecturer fac text book) gives lamina fully developed flow length at l= 0.05*Re*D. turbulent developed flow is approximated at l = 10*D. either way those nozzles are going to create nice pipe flow.
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