|
Here is a link to Steward Warner site with tips and
information on radiator parameter. Very good information
I've found no better,
credible source of information that is easy to understand - the best
part -> no math required {:>)
Regarding double pass radiators - like anything else there
are pros and cons. Here is an extract from that site:
Double pass radiators require 16x more pressure
to flow the same volume of coolant through them, as compared to a single pass
radiator. Triple pass radiators require 64x more pressure to maintain the same
volume. Automotive water pumps are a centrifugal design, not positive
displacement, so with a double pass radiator, the pressure
is doubled and flow is reduced by approximately
33%. Modern radiator designs, using wide/thin cross sections tubes, seldom benefit from multiple pass configurations. The
decrease in flow caused by multiple passes offsets any benefits of a high-flow
water pump.
The one basic equation of heat transfer Q = mDT/Cp. So if you reduce the mass flow m by 33%- that is
going to have equal reduction in heat transfer (Q). Now if the double pass
causes a better DT then you recover some of the heat
transfer, but all 33% lost to less mass flow?
Now if you can get the flow back up then the double
pass offers benefits. A higher capacity/higher pressure pump capable
of producing 16 times more pressure - or some means to increase flow
would seem desirable.
The bottom line is you can not consider just one aspect of
a cooling system and overly optimize on it. You cooling system is exactly
that - and it is a system which is no better than the weakness link in the
cooling chain, be it coolant flow, heat transfer characteristics (# fins/sq
inch, thickness, surface area, etc), air flow, specific heat of coolant and
on.
Frequently you will find (as Tracy recently pointed
out) that it is the small details that makes one system successful and another
seeming similar system not.
Will a double flow work - certainly it will - given enough
heat transfer surface and airflow across it almost any cooling system can be
make to work. The question is what (as always) are the trade
offs?
Ed
Sent: Friday, June 15, 2012 11:17 PM
Subject: [FlyRotary] Re: inlets and outlets
The double pass radiator increases the
efficiency of the radiator by about 50%.
You have tanks on both sides. One side has a
partition in the tank with the inlet at the top and outlet at the
bottom.
The coolant flows across the top half of the
core into the non-partitioned tank then back across the lower half back to the
partitioned tank and out the outlet.
That's the way I went with a custom Ron Davis
radiator.
On Fri, Jun 15, 2012 at 9:49 PM, <CozyGirrrl@aol.com>
wrote:
I can certainly see the logic in a single pass radiator of in on top and
out on bottom.
With a dual pass design (tanks top and bottom) what would be the
advantage of inlets and outlets on the bottom -vs- the top in a case with the
water pump above the top of the radiator?
In both cases their would be a vent line to the swirl pot from the
top tanks.
...C&R
No virus found in this
message.
Checked by AVG - www.avg.com
Version: 2012.0.2180 / Virus
Database: 2433/5072 - Release Date: 06/15/12
|