The
only problem is, I don't know anybody in the amateur-builder
community
who is doing this, and I don't know whether the cores that you
folks
are using come with the necessary information already provided by
the
manufacturer. It is, after all, much easier to pick two points off a
plot
than to derive them from tests
If
anybody out there has manufacturer's pressure drop and/or heat
transfer
data for a core or finished radiator that he could scan and
send
me, I would be most grateful. It doesn't matter what core - I just
need
to test my work so far against real hardware currently on the
market.
Regards
to all,
Marc
de Piolenc
Mass
Flow
http://www89.pair.com/techinfo/MassFlow/ductbook.htm
Marc;
I have two custom
radiators and a custom oil cooler. I have some data that may be useful;
from the maker and some I measured. Infortunately right now I can’t
locate the air side data I took on the two radiators – two spreadsheet
files that seem to have disappeared; and I can find no manufacturers data on
one of the rads.
Radiator: Ron Davis Racing
double pass, 2 rows of 1” tubes, 16 fins/in, core size 11.5 x 16 x 2.5
Conditions: coolant flow
– 20 gpm inlet temp – 200F
Air
flow 2600 cfm inlet temp – 90F
Manufacturers data :
Coolant pressure drop – 2.25 psi
Airside pressure drop – 0.175 psi
Heat dissipation – 2898 Btu/min
As I recall, my
airflow test data showed air side PD slightly lower.
Oil Cooler: Griffin Thermal
Products Single pass, 1 row 3.35” wide extruded tubes with internal
fins, 14 fins/in, core size 5.4 x 21.5 x 3.35
My measured air side
data:
|
fpm
|
FPS
|
IN. H2O
|
CFM
|
|
598.4
|
9.97
|
0.26
|
400.93
|
|
915.2
|
15.25
|
0.50
|
613.18
|
|
1196.8
|
19.95
|
0.76
|
801.86
|
|
1328.8
|
22.15
|
0.88
|
890.30
|
|
1522.4
|
25.37
|
1.12
|
1020.01
|
|
1700
|
28.00
|
1.32
|
1125.60
|
|
1900
|
31.00
|
1.56
|
1246.20
|
|
2100
|
34.00
|
1.84
|
1366.80
|
|
2300
|
37.00
|
2.12
|
1487.40
|
|
2500
|
40.00
|
2.44
|
1608.00
|
The first five points
are measured, the last five extrapolated using a regression analysis fit which
matched the measured data very well.
The manufacturers data
that I have is for the same tube/fin configuration, for what they called a “similar”
design, actual measured data. I don’t know how useful it is because I don’t
know their actual core dimensions.
Oil inlet – 220F,
Oil flow – 18gpm, Delta P – 28 psi, oil outlet – 185F
Air inlet – 100F,
Air flow – 1575 cfm, Delta P – 1.48”
Heat rejection –
2380 Btu/min
The flow rates, temps,
and heat dissipation is very close to my design point.
I also did pressure
tests on the cooler; cycled 5 times to 125 psi – no problems. The
extruded tube is very interesting; thin ribs about every 5/16” that
connect the tube wall, with 3 small intermediate fins.
FWIW,
Al