Good ideas Scot- actually this is not a misuse of Bernoulli, because it is not Bernoulli's Principle- but (Evangalista) Torricelli's Theorem- about 350 years ago- velocity of efflux
-----Original Message----- From: å... .... [mailto:[email protected]] Sent: Tuesday, April 05, 2011 4:41 PM To: [email protected] Subject: Another design solution needed in all seriousness, why can't TD do a "bucket test" ;-) or in the least, pitot the main drain flow? Below are a couple of ways to go. 1. Bucket test would take the drain from the main into some big storage thing and count the gallons over...say 30 seconds, that is Q. Done. You got Pstatic, Presidual, and Q, at a point near the BoR. Don't know what kind of "big storage thing" you are going to use, but that approach is what I would chose, rather than an application of Bernoulli's that was misused. 2. take a low volume pitot to the main drain discharge and get Q that way. 3. Use Bernoullis anyway, but apply it properly. P1 static pressure at gauge v1 zero h1 height at gauge (not ceiling) P2 residual pressure at gauge v2 what we be looking to solve (can be cross checked with low volume pitot) h2 height at gauge we could alternatively take another location on the streamline as our point "2" and drop all consideration to the bucket test/pitot flow. P2 0 psi gauge pressure at main drain discharge v2 what we solve for (and cross check by low volume pitot) h2 height at main drain discharge scot deal excelsior fire engineering P.S. How accurate is the pressure gauge on the riser/main drain anyway? On Wed, Apr 6, 2011 at 1:17 AM, Todd Williams <[email protected]> wrote: > Uh..... > > I'm not sure Brad's assumptions on the flow are valid. V = sqrt(2gh) is for > an object in free fall, discounting any friction or drag. I don't think you > can apply it to discharge through an orifice. _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
