THIS LETTER REPORT SUMMARIZES THE EFFORT UNDER TASK ORDER NO. P DURING THE PERIOD MAY 31 THROUGH DECEMBER 31, 1957.

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03642A001500060006-3
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 11
• Document Creation Date: December 22, 2016
• Document Release Date: June 13, 2012
• Sequence Number: 6
• Publication Date: January 3, 1958
• Content Type: LETTER

5 17?
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
25X1
Dear Sir:
This letter report summarizes the effort under Task
Order No. P during the period May 31 through December 31, 1957.
The objective of this activity was the preparation of a gas-
metering handbook, based on hydrogen as the working fluid, for
use in connection with balloon inflation. The principal function
of the handbook was to provide tables of lift at various pressures
and temperatures; pressure, in atu (atmospheres, gage), ranged
11
from 0.5 to 200 atu, and temperature from -40 to +40 C (-40 to
+104 F).
Development of Lift Equation
As a first step, it was necessary to derive an equation
for determining lift, so that a program for the 650 Computer
could be written. The derivation may be summarized as follows:
The working fluid was assumed to be hydrogen with a
small amount of nitrogen as an impurity. The gas mixture for
which calculations were made was 98.5 mole per cent hydrogen and
1.5 mole per cent nitrogen.
The total available lift is given by the volume dis-
placed, multiplied by the density
involved, or:
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
difference
I
/
for the gases
- _ ___r_ w
s,vvir, t/ BY
_..?_!_._ 07p
MO CLASS j_____ pAns ?0--- uiv GLAsz JC,
I
JUST _____22? N1N7 nay _2022_ OTAa V,i
,, ----3
cC`r.1, I.' .17T7i
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
(
/
/
-2- January 3, 1958
Lift = (d - d)V
a m
d,
where da = density of the air displaced
dm = density of the hydrogen-nitrogen
mixture
Vd = volume of gas mixture delivered.
(1)
The densities were calculated from the ideal gas law,
with a compressibility factor included to compensate for deviations
from ideality (PV = znRT):
(2)
V zRT
where P = pressure in atmospheres
R = gas constant in liter atm/?K-g-mole
T = absolute temperature in degrees Kelvin
z = compressibility factor
M = molecular weight
d = density?
Since the average molecular weight of a 98.5 per cent
hydrogen-nitrogen mixture is 2.41, at atmospheric pressure:
given by:
d _ 0.02929 kg/liter.
(3)
The average molecular weight of the air displaced is
M - 1 x 28.96 + H x 18.02,
1 + H 1 +H
where H = absolute humidity in moles of water
per mole of dry air.
r
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
(4)
? LT?
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
) 1_1
-3- January 3, 1958
From Equation (2):
d = 1 (28.96 + 18.02 H).
a zRT 1 + H
From saturation data*, a relation between H and the
absolute temperature in degrees Kelvin was determined for a
percentage humidity of 68:
H = 1.561 x 1000257 T - 9.518
(5)
(6)
The volume of air displaced is equal to the volume of gas
mixture delivered:
ndRT
- -
u zr2
(7)
where P2 = balloon pressure
nd = number of moles delivered to the balloon
Also, nd = n1 - n2 = the initial number of moles
in the cylinder minus the number of
moles after evacuation.
P1Vc
111
zRT
where P1 = the initial pressure in atmospheres
Vc = cylinder internal volume in liters.
PVC
n2 -
zRT
where P = 1.5 atmospheres (in order that the
(8)
(9)
residual gas remain pure, it is expected
*John H. Perry, "Chemical Engineers' Handbook?, 1941, p 1082.
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
r-,
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
" C_))
-4- January 3, 1958
that the operator will leave a residual
11
pressure of 0.5 atu)0
z = approximately 1.001 over the temperature
range involved.
Thus, we have:
V, P
n = n n = -= i - 1.4988) g-moles.
d 1 2 RT z
From Equation (7) we have:
(10)
ndRT
Vd = - ndRT = Vc (-= - 1.4988) liters. (11)
zP2
Substituting Equations (3), (5), (6), and (9) in
Equation (1), combining constants, and simplifying, for the 6-cubic-
meter cylinder we have:
Lift = (12)
.8.218_2(111_ 1.1+988) (1.607 + 1.561 x 100.0257T - 9.518
T z - 0.1334).
1 + 1.561 x 100.0257T - 9.518
If the factor of humidity had not been considered, an
error of over 3 per cent in lift could result. By the assumption
of 68 per cent humidity (an average value determined from
conditions in major U. S. cities), the possible error was reduced
to less than 1 per cent.
Jf )1 H I
!,3?Ii
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
r-z? ET73-
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
1;\\
-5- January 3, 1958
Correlation of Data and Determination
of Equation of State
In order to solve the derived lift equation at the
desired conditions of temperature and pressure, an equation of
state for the gaseous mixture was required. Since for the most
part experimental P-V-T data are given in the form of compressi-
bilities, it is most convenient to retain this means of expression.
As seen earlier, the lift equation is written in terms of pressure,
temperature, and compressibility only.
A literature search was undertaken to gather data on
gaseous hydrogen and nitrogen. The data obtained appeared as
compressibility versus absolute pressure in atmospheres at various
Kelvin temperatures. A relation between these variables was
determined, with the aid of the 650 Computer, in the following
manner:
For both gases, a relation of the form z = A + BP + CP2
was assumed for each isotherm. The constants were evaluated by
the method of least squares, giving a set of A, B, and C values
at each temperature considered. In a similar manner, these values
were related to the absolute temperature by least-squares fits
2
of the form A = a + bT + cT for each gas.
*"Tables of Thermal Properties of Gases", U. S. Department of
Commerce, N.B.S. Circular 564, pp 271-274, 317-323.
H. L. Johnston and D. White, "PVT Relationships of Gaseous
Normal Hydrogen", Transactions ASME, August, 1950, pp 785-787.
Deming and Shupe, "Physical Review", 1931, p 638.
\{)) )1
n A
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
Declassified in Part - Sanitized Copy Approved-forr-Rfeeraser-28J1'2/06/13 : CIA-RDP78-03642A001500060006-3
r
-6- January 3, 1958
If Amagat's Law is assumed to apply, the mean compressi-
bility factor of a mixture may be given by zm = xizi + x2z2, where
x is the mole fraction. It has been shown* that for mixtures of
hydrogen and nitrogen, especially in the purity range considered,
this assumption may be safely made. The corresponding constants,
e.g., aH and aN2, were thereby combined, resulting in a final
2
relation of the form:
zH -N = A' + B'P + C'P2,
2 2
where At = a' + b'T + c'T2
B' = d' + e'T + f'T2
2 ,
C' =g' + h'T + j'T!
(13)
Substituting the constants, as determined by machine computation,
we have:
z = 0.990 + 7.o9xio-5T - 1.24x10-7T + (7.66x10-4 - 1.39xi0-9T)P
+ (3.24x10-6 - 1.74x10-8T + 2.45x10-11T)P2. (14)
Substituting Equation (14) in Equation (12) results in
an equation relating lift with temperature and pressure only.
General Description of Handbook
The inflation tables constituted the bulk of the hand-
book.
*Hougen and Watson, "Industrial Chemical Calculations", 1936,
p 4o4.
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
.(71, Frrl, FP r-TP
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
-7- January 3, 1958
However, it was necessary to provide introductory
information on the handling of hydrogen cylinders and the use of
the handbook, together with related conversion charts or tables.
The discussion and descriptive material, tables, and charts that
were provided as introductory sections in the handbook are
indicated below:
A. Discussion and descriptive material
(1) Description of hydrogen cylinders and
controls commonly encountered
(2) Description of tables included in the
handbook
(3) Discussion of safety measures
(4) Discussion of weight of flight equipment
and free lift
(5) Description of recommended temperature-
measurement procedure
(6) Description of recommended pressure-
measurement procedure
(7) Discussion of conversion factors for
cylinders other than the German 6-cubic-
meter size on which the inflation tables
were based
(8) Discussion of corrections for gas
impurities other than 1.5 per cent
nitrogen
1i I
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
( ntc21!,;)
-8- January 3, 1958
(9) Discussion of partial-cylinder
correction
(10) Sample problems illustrating the
use of the handbook.
B. Tables
(1) Cylinder-conversion factors. This
table lists a number of standard
German and U. S. cylinders together
with the conversion factors, determined
from the following relationship:
Lift Determined
Conversion Factor _ From Inflation Tables.
Actual Lift From
Cylinder
The reason that this simple conversion
is possible can be found by examining
Equations (1) and (9) above, which show
that lift is a direct function of
cylinder internal volume.
(2) Lift-conversion table. This table converts
from pounds, force, to kilograms, force,
and covers the range from 0.1 to 22.5
pounds in 0.1-pound increments.
(3) Pressure-conversion table. This table
converts from atu (atmospheres, gage) to
psig (pounds per square inch, gage), and
covers the range from 0.5 to 200 atu in
0.5-atu increments.
lf
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
F:11 C-7-1
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
`11-
Q.)
--9- ,January 3, 1958
C. Charts
(1) Correction charts for gas impurities.
Correction charts are provided for
impurities of nitrogen, oxygen, carbon
dioxide, and ammonia. To simplify the use
of the charts, the compensation for
impurities is based on 15 C and is correct
at only that temperature. The correction
applicable at other temperatures will be
in error to the extent that the compressi-
bility factor varies with temperature.
However,
the compressibility factor varies
with pressure to a much greater degree than
with temperature, and for this reason
pressure was used as a parameter on the
correction charts. The correction is:
Fractional Lift (Correction Factor) =
Actual Lift
Lift Determined From Inflation Tables
(2) Partial-cylinder correction chart. If a
cylinder is partially drained, expansion
of the gas causes cooling, which reduces
the pressure in the cylinder. If the
cylinder is allowed to warm to ambient
temperature, the pressure will increase.
When the cylinder is again at equilibrium
Declassified in Part - Sanitized Copy Approved for Release2012/06/13: CIA-RDP78-03642A001500060006-3
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
?
\
-10-
January 3, 1958
with the ambient temperature, the
inflation tables can be used to determine
the amount of lift remaining in the
cylinder. However, it is normally desirable
to determine this value immediately after use
of the cylinder. For this reason, the
partial-cylinder correction chart has been
provided to permit estimating the pressure
to which a cylinder should be drained in
order to yield the desired equilibrium
pressure. The degree of cooling, and
therefore the pressure loss for any
cylinder, depends upon a number of factors,
such as rate of discharge, and size and
mass of the cylinder.
To develop this chart, a number of U. S.
Linde Standard 191-cu-ft cylinders were
drained and data taken as to the instantaneous
and equilibrium pressures. Since these
cylinders are nearly the same size as the
German 6-cubic-meter cylinder (conversion
factor for the Linde Standard cylinder is
0.949), the data provided by the chart
are equally applicable to the German
cylinder.
/"A.,
7=1 F:D CT/
,IAIL13
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
(-HI-11(1)043:j'
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
y 2 LJ
-11-
January 3, 1958
The gas-metering handbook developed in the course of
this project will provide an accurate means of determining the
degree of balloon inflation necessary to obtain a desired lift with
a minimum of computation. The handbook was reproduced, and 250
copies will be sent to the Sponsor in the near future.
We would appreciate receiving any comments that you
or your associates might care to make on the handbook prepared or
the work done on this project.
In Triplicate
'
1,7 11 l?
Declassified in Part - Sanitized Copy Approved for Release 2012/06/13: CIA-RDP78-03642A001500060006-3
25X1
25X1