Message text written by INTERNET:Davgil@aol.com
>........Specifically, I am
thinking of my TR 6, which has a shroud to direct airflow to the radiator.
If
this is partially blocked by a cooling fan, would a portion of the air not
be
prevented from entering the radiator and may bypass the engine compartment
altogether? If the air penetrates the radiator, even though there is a
partial
dam created by the pull location of the fan, it seems that there would be
more
air around the engine and oil pan to carry off excess heat......<
Speculating again but I wonder how much of the air caught by the grill
openings actually goes through the radiator. As speed increases the
resistance to airflow by the radiator alone will increase and this will
create a pressure front with will cause some fo the air in the path of the
grill to spill up over the hood and off to the side of the fenders. Some
will also try to spill under the car. If your TR6 has an air dam it will
redirect some of it back into the que of air waiting to pass through the
radiator (euphimism alert) but still some will find its way underneath
where it will help cool the oil via the oil pan.
Putting a fan in the path will increase the resistance to air flow
reguardless of whether it is in front of or behind the radiator. Its
proximity to the radiator can shade parts of the radiator and litttle heat
transfer will occur at those areas on the radiator. However the air that
is deflected will pass through the radiator at some other location and will
increase the amount of heat transfer in increase. This process is not
quite linear and doubling the air flow does not necessarily double the heat
transfer but the heat transfer that would have been gained by not shading
the radiator with a fan is not lost completely.
But the real hard part is the quantitative analysis. If anyone wishes to
give me a $20,000 grant I will get some mechanical engineering students and
we will give this a rigorous analysis with experimentation and mathematical
modeling.
Or we can just say "mount it where it is convenient."
Dave
|