Need calculator for Annulus flow

[sprintcar]

HELP!! Need calculator for Annulus flow!!
I need a spreadsheet (or formulas) to calculate and graph water flow thru an annulus formed by the gap between a circular orifice (square edged) surrounding a shaft. Variables will be water pressure, orifice ID, orifice thickness, and shaft OD. Temperature will be constant (probably 70F). I can dig thru Cameron’s but I figure somebody in our great group of Engineers probably already has one. (I’ll post this in a couple forums) THANKS!!


"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein

 

[abeltio]

sprintcar...
there is more to this problem than meets the eye...
according to CRANE flow of fluids technical paper #410, page 1-4...

quote
for extremely narrow shapes such as ANNULAR or elongated openings... in such cases the hydraulic radius is approximately equal to one-half the width of the passage.
unquote

the hydraulic radius is used to calculate the reynolds number (Re)... according to CRANE, using 1/2 of the gap enables you to calculate the flow.

neverthelesss... if this is a shaft... the gap could be really tight (a couple of thousands of an inch)... and if the shaft rotates, depending on the rpm's you could have a completely different situation, because the flow will be affected by the drag created by the shaft and the extremely low gap (laminar flow?).

sorry.




saludos.
a.

 

[sprintcar]

Thanks abeltio -
The gap to the shaft is on the order of 2mm so we can eliminate the rotation from the problem. The width of the orifice plate varies but is typically about 10-12mm.
This is for a stuffing box (gland) on a pump. The calculations are to determine flow when there is no packing.


Thanks!!

"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein