G'day Randy,
Thanks for your reply, and yes I would like to discuss this further. I will be on site Monday and shall take some internal bore measurements first though.
Thanks for you help.
Cheers for now
Robin
> I believe the Ductile Iron Pipe Research Association ("DIPRA"), in
conjunction of course with I suspect interested Owners of the specific
pipeline systems, has accomplished hydraulic testing on at least a few
installed actual (u)pvc systems that are referred to on page 9 of 14 of
their publication at http://www.dipra.org/pdf/DIPvsPVC.pdf . This was as I
understand it in the fashion of a great many more hydraulic tests they have
performed with a great many other interested Owners of actual iron piping
systems over many decades. While I heard no mention in conjunction with
their detailed reports of this pvc flow testing that any internal "ripples"
were evident in those specific piping systems (nor that such phenomena was
even known to DIPRA at that time), I believe the installed pvc piping in all
those cases (that I believe had been installed just a few years) achieved an
actual H-W "C" many points below what the pvc industry claims. I doubt
internal waves, ripples, or whatever will help much, and in my personal
opinion hydraulic and other system performance is dependent on many more
factors than perception, an interior smooth to the touch in localities, or a
the visibly smooth external surface everyone sees! I suspect interested
pipeline Owners/consultants could obtain copies of the actual detailed flow
testing technical papers from DIPRA, if they are interested.
> Apparently, however some others are aware at least of "wavy" pvc internal
conditions, as I saw this mentioned recently (on page 640 of Appendix C of
the hardcopy), in the table "C-factors for various pipe materials" in the
extensive technical publication from Haestad/Bentley, "Advanced Water
Distribution Modeling and Management". I have also noticed that this
publication/data is now viewable online at
<a href="http://www.haestad.com/library/books/awdm/online/wwhelp/wwhimpl/java/html/wwhelp.htm">http://www.haestad.com/library/books/awdm/online/wwhelp/wwhimpl/java/html/wwhelp\
.htm</a>
(I believe the H-W data is under "Tables" "C." there).
> While I do not look at much of this pipe, I believe I have incidentally
seen such internal pvc wavy or lumpy conditions on a few occasions myself,
the last being what I happened to see same in a piece of pipe that was sent
to our research laboratory for unrelated mechanical testing of the material
a few years ago (we did/could not test that one piece of pipe for flow
properties). I have a couple photographs of the internal conditions of that
particular pipe I received, if you wish to compare notes off this list.
>
> Randy Conner
>
> -----Original Message-----
> From: <a href="/group/PipingDesign/post?postID=1CUSEsFiX6nEn7jz0RIFEeW38LVgDy92Klk7wntKYyNkDsGNyAhKlNQsJ5LnpB3kqghAmoDguE0ojryXGiDkqAofcOY">PipingDesign@yahoogroups.com</a>
> [mailto:PipingDesign@yahoogroups.com]On Behalf Of Robin Badcock
> Sent: Wednesday, August 03, 2005 6:17 PM
> To: <a href="/group/PipingDesign/post?postID=1CUSEsFiX6nEn7jz0RIFEeW38LVgDy92Klk7wntKYyNkDsGNyAhKlNQsJ5LnpB3kqghAmoDguE0ojryXGiDkqAofcOY">PipingDesign@yahoogroups.com</a>
> Subject: [PipingDesign] Pipe friction
>
>
> Dear group,
>
> We have had new 250 PN 6 UPVC RRJ pipes delivered to site; these pipes
have a very ripply finish inside the entire pipe barrel. This is for all
pipes (1350m)
>
> Ordinarily, a pipe of this size and construction would attract a
Hazen-Williams coefficient of; C-151.(Australian Pump Manufactures Pipe
Friction Handbook).
>
> The question has been asked as to what influence the ripply bore may have
as to increasing energy losses.The ripples are perhaps more like elongated
smooth scales that are overlapping somewhat so as to have a layering effect.
They are smooth to touch and are approximately 13mm in length, 10mm in
width, and are oval in appearance. The protrusion into the water flow (above
what would be considered the normal pipe barrel base line) is in the order
of 0 .75-1mm. Hence, from the crest of one scale to the valley of the next
adjacent scale is approximately 1mm.
>
> Question: I seek suggestions as to what the new coefficient may be
estimated at;
> and I seek suggestions as to where information may be
gleaned to reinforce this information/suggestions.
>
> I have been scouring my hydraulics manuals with some success, although
there seems to be more information on all the other Friction Loss Equations
that have ever been cooked-up. I guess I could work through some of the
other formulas and extrapolate the information across so as to get a rough
indication as to the new C value, but hey you Dudes are far smarter than I
and I am curious as to what may arrive in my mail box.
>
> Cheers for now and thanks.
>
> Robin
>
> [Non-text portions of this message have been removed]
>
>
>
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Received on Sat Aug 06 05:03:00 2005
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