Pressure drop through annular ring

[BoomerSooner7]

Anyone have a formula for pressure drop through an annular ring. I have found very limited information on the web, but from what I've found the pressure drop is different than that of an orifice because there are two separate surfaces with the ring. Any advice would greatly be appreciated.

 

[hydtools]

I think my Yeaple book may have an article on it. I'll check.

Ted

 

[ione]

Suggest you give a read to the FAQ below, written by respectful member zds04 (Mr. David Simpson)

http://www.eng-tips.com/faqs.cfm?fid=1142

 

[BoomerSooner7]

Wow, that result is much different than I anticipated using the link below from a fluid power handbook. I calculated the effective area using the Petroleum engineering on your post and came out with a lot lower pressure drop than the formula used on the link below. Copy and paste it into your browser. We're you able to find anything in your fluid power book? Thanks.

http://books.google.com/books?id=K2CkjoYZDDUC&pg=PA259&lpg=PA259&dq=leakage+

 

[katmar]

The FAQ by zdas04 is for flow in annular pipes whereas it seems that you are more interested in an orifice plate of sorts. Pressure drop in pipes is all about wall friction, but pressure drop through an orifice is all about entrance and exit effects so I would not expect them to give similar results.

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[hydtools]

This from a Lenkei article in Yeaple's 1966 edition of Hydraulic and Pneumatic Power and Control:

Units are Imperial: ft-lb-sec system

P1-P2 = W^2/(2*g*rho*K^2*A^2)

Reynolds number for annular orifices: Re = W*(D-d)/(A*mu*g)

Find K from a chart. See fig 5, page 39 in the attached link.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680014519_1968014519.pdf

radial clearance v. K for various Re

A, flow area, ft^2
d, minor diameter, ft
D, major diameter, ft
g, 32.2 ft/sec^2
K, orifice coefficient
L, flow length, ft
P, pressure, lb/ft^2
V, fluid velocity, ft/sec
mu, absolute viscosity, lb sec/ft^2
W, flow rate, lb/sec
rho, density, lb/ft^3

Yes, it is an older book.

Ted

 

[BoomerSooner7]

I found a program that calculates dP in an annular orifice, it's called Pipedrop from G&E Engineering. The results are very close to the formula listed above in the link I sent. I think the best approach is to build a simplified test apparatus and gather real data. Thanks for all the posts guys.

 

[danw2]

Does the annular orifice look like this?

If so, 3 pages from R. Miller's Flow Measurement Engineering Handbook are attached.

 

[danw2]

3rd page is above
here's 1st page

 

[danw2]

and 2nd page