I searched the CD and found this data on the ability of
air to absorb heat.
I wrote a little program to calculate the area required
at 100 MPH and 120 MPH as a function in the increase in
air temp passing through the rad. Not sure about the
specific heat constant so by all means check my calculations.
As you can see in the ideal case where the air is increased
by 60 degrees exiting the rad the area required is about 200 square
inches or about 10 by 20 roughly 63% of the frontal area of a 320
square inch rad. Sounds real high so there could be something
wrong. Sounds like it is off by a factor of two.
Tracy promised to measure the air temp and air velocity
exiting his rad.
Assumptions:
6000 BTU per minute waste heat
Specific heat of air = 0.01988 BTU per cubic foot per deg
20% humidity 100 degree day
Forward speed 100 MPH 147 FPS 8820 FPM
Flow through rad is 40% of 8820 FPM or 3528 FPM
____________________________________________
|air temp | airflow req | area | area |
| rise F | CFM | SF | SI |
--------------------------------------------
10 30303 8.59 1237
15 20202 5.73 825
20 15152 4.29 618
25 12121 3.44 495
30 10101 2.86 412
35 8658 2.45 353
40 7576 2.15 309
45 6734 1.91 275
50 6061 1.72 247
55 5510 1.56 225
60 5051 1.43 206
Assumptions:
6000 BTU per minute waste heat
Specific heat of air = 0.01988 BTU per cubic foot per deg
20% humidity 100 degree day
Forward speed 120 MPH 176 FPS 10560 FPM
Flow through rad is 40% of 10560 FPM or 4224 FPM
____________________________________________
|air temp | airflow req | area | area |
| rise F | CFM | SF | SI |
--------------------------------------------
10 30303 7.17 1033
15 20202 4.78 689
20 15152 3.59 517
25 12121 2.87 413
30 10101 2.39 344
35 8658 2.05 295
40 7576 1.79 258
45 6734 1.59 230
50 6061 1.43 207
55 5510 1.30 188
60 5051 1.20 172
CLS
BTUCon = .01988
OPEN "btu.dat" FOR OUTPUT AS #1
PRINT #1, "Assumptions:"
PRINT #1, "6000 BTU per minute waste heat"
PRINT #1, "Specific heat of air = 0.01988 BTU per cubic foot per deg "
PRINT #1, "20% humidity 100 degree day"
PRINT #1, "Forward speed 100 MPH 147 FPS 8820 FPM"
PRINT #1, "Flow through rad is 40% of 8820 FPM or 3528 FPM"
PRINT #1, "____________________________________________"
PRINT #1, "|air temp | airflow req | area | area |"
PRINT #1, "| rise F | CFM | SF | SI |"
PRINT #1, "--------------------------------------------"
FOR tempF = 10 TO 60 STEP 5
PRINT #1, tempF;
airflowCFM = (6000 / (.0198 * tempF))
PRINT #1, USING "############"; airflowCFM;
AreaSF = airflowCFM / 3528
PRINT #1, USING "###########.##"; AreaSF;
AreaSI = AreaSF * 144
PRINT #1, USING "###########"; AreaSI
NEXT tempF
CLOSE
OPEN "btu.dat" FOR APPEND AS #1
PRINT #1, "Assumptions:"
PRINT #1, "6000 BTU per minute waste heat"
PRINT #1, "Specific heat of air = 0.01988 BTU per cubic foot per deg "
PRINT #1, "20% humidity 100 degree day"
PRINT #1, "Forward speed 120 MPH 176 FPS 10560 FPM"
PRINT #1, "Flow through rad is 40% of 10560 FPM or 4224 FPM"
PRINT #1, "____________________________________________"
PRINT #1, "|air temp | airflow req | area | area |"
PRINT #1, "| rise F | CFM | SF | SI |"
PRINT #1, "--------------------------------------------"
FOR tempF = 10 TO 60 STEP 5
PRINT #1, tempF;
airflowCFM = (6000 / (.0198 * tempF))
PRINT #1, USING "############"; airflowCFM;
AreaSF = airflowCFM / 4224
PRINT #1, USING "###########.##"; AreaSF;
AreaSI = AreaSF * 144
PRINT #1, USING "###########"; AreaSI
NEXT tempF
CLOSE
SHELL "more < btu.dat"
SYSTEM
Paul Lamar
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