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Unread 11-02-2002, 07:58 PM   #239
bigben2k
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Join Date: May 2002
Location: Texas, U.S.A.
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Quote:
Originally posted by morphling1
As I know Reynolds number is v*d/kinematic viscosity

v.... velocity [m/s]
d... diameter [m]
kinematic viscosity [m2/s]

if the chanell isn't round you have to take the equivalent hidraulic diameter d' = 4*A/C
A... cross area [m2]
P... circumference [m]

so for bb2k rectangular chanell d'=2ab/(a+b)
So you can see that narrow rectangular chanell isn't realy too good for introducing turbolence round chanell is much better.... but with central nozzle and short paths I realy don't think that there would be lamilar flow in that kind of block
It's Saturday... I've tested my airtrap (with some success: the thin wall vynil tubing just collapses, otherwise all air is cleared within 10 seconds).

I'm recalculating the different radius' involved: boy was I off!

Doing a quick recalc of Reynolds# at center, assuming the last design posted (center square post):
-opening size (for trial): 5mm diameter, aka 3/16 inch.
(At 4 gpm, I loose 2 feet of head!)
-Velocity: 40 m/s
-4 openings measuring 1 by 5 mm (still not accurate)

Quote:
if the chanell isn't round you have to take the equivalent hidraulic diameter d' = 4*A/C
A... cross area [m2]
P... circumference [m]

so for bb2k rectangular chanell d'=2ab/(a+b)
(I assume that the "C" in the equation is "P"?)

where
a=.001
b=0.005
A=0.000005
P(or C?)=0.031

so
d'=.00167 (using: 2ab/(a+b) )
multiply by 4 (4 channels)
d' becomes .0067

so Reynolds = ... What is "dynamic viscosity"?
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