That kind of thinking is pretty suspect, but in order to really compare the
effectiveness of the radiator construction you have to look at all of the
contributing factors:
- The radiator core is not made of either pure aluminum or pure
copper, and a little bit of alloying metal can have a large effect on the heat
transfer coefficient.
- The cores are THIN. Therefore, the heat transfer coefficient of the
core is not as critical as the surface area of the tubes and whether or not the
coolant flow through the tubes is laminar or turbulent; or whether or not the
airflow between the tubes is laminar or turbulent.
- Most brass radiators have the cores lined up in a row. The third or
fourth row does not do much cooling. Most aluminum radiators have only two rows
of fins, and they may be staggered so that each row has more exposure to the
incoming airflow. Part of the reason that aluminum rads work better in many
applications may simply be that they flow much more air.
- Gotta look at long-term chemistry in the cooling system too. What
happens to your coolant over time b does it coat the internals of your cooling
system with a layer of gunk? If so, it may clog the core tubes; at least, the
cooling system efficiency will be determined by the heat transfer coefficient
of the gunk rather than the core tubes. I donbt know if aluminum is
intrinsically better than brass there b but I will be careful to run distilled
water/coolant mix as opposed to a tap water mix, so as to prevent issues with
calcium deposits.
Theo
From: CoolVT@aol.com [mailto:CoolVT@aol.com]
Sent: March 21, 2012 10:58 AM
To: Smit, Theo; tigers@autox.team.net; dave@munroe.ca
Subject: Re: [Tigers] Tiger Cooling
Theo,
I agree with directing the flow through the radiator and blocking the proper
areas. I have done everything that you've done in that area.
In regards to the type/material of the radiator. I was at a show recently
where a radiator supplier (all aluminum models) had about 100 rads on display.
Most were ready made for certain cars. I was impressed because the prices
looked awfully good. He said they could make up any configuration that someone
would want. I asked how much more efficient aluminum would be over brass for
the same size. He said about 25%. I said that I thought the brass would be a
better conductor or heat and therefore more efficient. He said "no". He said
you put your hand on a brass radiator after a hard run with a car and you'll
burn your hand. Do the same with an aluminum and it will feel cool. This, in
his mind, was saying that since the al. felt cooler that it was dissipating
heat better than the brass. I came to the conclusion that he was probably not
someone i would want designing a radiator for a Tiger.
Mark
In a message dated 3/21/2012 12:43:10 P.M. Eastern Daylight Time,
Theo.Smit@dynastream.com writes:
Hi Mark,
I donbt think that there are any quick cooling aids for the Tiger b all of
them require attention to detail to get more than just a marginal benefit.
The Cressida fan is about 12b diameter and has an integrated steel shroud; it
just barely fits below the sheetmetal in the nose. I used foam adhesive tape to
seal the gap between the rad matrix and the shroud. The problem you always have
with pusher fans is that the motor obscures some of the available area; a
second thing is that if the gaps arenbt filled, then the air can just go out
the side rather than through the radiator. The reason why I used this fan is
that it was evidently designed from the outset as a pusher application. A lot
of aftermarket fans are designed as a puller, and then when theybre used in a
pusher application they really donbt move anywhere near the air that theybre
supposedly rated at.
The only thing that would be nice is to have a similar fan, but larger, so that
it would move more air over more of the radiator. Youbd end up with part of
the fan output deadheading against the lower radiator support though.
Moving air through half the rad should be more than sufficient, since the fan
is only required to boost airflow at low speeds. You just have to make sure
that the air youbre moving is really going through the rad rather than around
it, and that itbs moving with sufficient speed.
A secondary issue is that if the fan only covers part of the radiator core, are
those core tubes actually flowing enough coolant to do the job?
Theo
________________________________
This e-mail and any attachments may contain confidential material for the sole
use of the intended recipient. If you are not the intended recipient, please be
aware that any disclosure, copying, distribution or use of this e-mail or any
attachment is prohibited. If you have received this e-mail in error, please
contact the sender and delete all copies.
Thank you for your cooperation.
_______________________________________________
tigers@autox.team.net
Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
Unsubscribe:
http://autox.team.net/mailman/options/tigers/tigers-archive@autox.team.net
|