WB performance differences due to internal geometry

[BillA]

in another thread dream caster inquired about "the perfomance changes with geometry" apparent from my testing of wbs

the short answer is:
No significant superiority that can be directly attributed to a specific wb configuration.

but I've not tested all wbs by any means, and new designs appear weekly
Danger Den, Dtek, and Silverprop have indicated an inclination to send their latest, so we shall see . .
(and I have a Swiftech, Innovatek, and Cooltech in testing)

Why is there no performance "winner" in terms of geometries ?

easy answer: because wb designers are still learning what works (and what does not),
and of course - the manufacturers are making what the consumers wish to buy.

Most (but not all, eh) mfgrs are terribly handicapped by a lack of accurate test data about their and their competition's products;
but this too is changing and the newer products are a reflection of this effort.

So why will testing not reveal the "best" configuration ?

Lets assume, for the purpose of discussion, that there are 10 design factors affecting - unequally - the ultimate performance of a wb design.
Given that each designer will 'favor' these factors differently, and that the 'as built' manufacturing process will be more, or less, effective in the actual implementation of the design;
then it is easy to understand how impossible is an attempt to reverse engineer a wb to extract the performance contribution of a single specific element.

But this limitation does not mean that testing cannot reveal, and quantify, performance differences.
Nor that such a collection of test results cannot be analysed to see if any 'trends' are apparent.
BUT one must be very judicious about drawing conclusions.
for example:
if a grouping of similar wbs does poorly compared to another, what is indicated ?
it could be that one design configuration is superior to another
or
that one of the designs is not yet (properly) developed

most of the wbs for sale today are quite undeveloped in terms of their design maturity
(did I state that gently enough ?)

be cool

 

[dream caster]

Thanks for your posting,
but is sad to know we don't know.


I had hoped you could expand a little those hints that you gave us in numerical modeling thread.

 

[nihili]

Bill,

*IF* you had access to a milling machine, how would you go about isolating and testing for the effect of geometry?

nihili

 

[BillA]

with a Cooltech housing

be cool

 

[Tecumseh]

At some point the mathematics of heat transfer has to
be a guiding factor. But, as you have so gently taught me,
blind application of formulas in the various papers can
lead one astray. This stuff can get messy, not unlike
organic chemistry which no sane person wants to
dabble in.

Unfortunately, even if you could throw all the physics
into a box with the ultimate simulator, you couldn't just
throw numbers into it and expect it to pump out the
perfect design.

But I'm with nihili. IF you had a mill, how would you
go about converging out YOUR best design.

Disclaimer: Yea, "optimal is not an engineering goal, it is a state of being." But you know what I mean.

 

[BillA]

nihili
perhaps I misunderstood your question
da capo
take an extreme of one parameter, and machining in 4 or 5 incremental steps go to the opposite limit
then bracket the 'high' point

Tecumseh
again
'best' for which design conditions ?
and economics ? (cost to mfgr vs. selling price)
relative performance ?

there could be a curve showing the cost vs. C/W - but no one has real data (or chooses to reveal it)

my 'best' design ?
something already made, with a very low pressure drop to permit a smaller pump (and note that I use a remote chiller)
--> because my goal is not high performance, its LOW NOISE

back to the design conditions eh ?
yes, I know what yours are, but "2 gpm" is an inadaquate definition
-> what is the pressure drop available to be expended across the wb (at a flow rate of 2 gpm) ?
look at the relationship between turbulence and head loss
look at the pump's PQ curve wrt the whole system AND the wb individually

a WCing kit designer has the advantage of knowing which pump is going to be used, as well as the general system characteristics

a wb (only) designer has to try for a compromise generally suitable for 'most' users
- making many assumptions some of which will preclude the 'best' (possible) performance

more could be said but it would distress DIY WCers

be cool