/!....--p\ ITIGil-IT P I C ~ S S U R E
I
DONNA PRICE and GEORGE
T.
LALOS
Naval Ordnance Laboratory, White Oak, Silver Spring, Md.
Adiabatic Compressor for P-V-7' Measurements on Gases to 100,000 Pounds per Square Inch After calibration with carbon dioxide to 20,000 pounds per square inch, P-V data on nitrogen could be obtained to about 25,000 pounds per square inch *
MOST
HIGH temperature studies have been carried out a t low pressures; high pressure work has generally been done a t low temperatures. Because a gas a t 100,000 pounds per square inch and 4000' K. cannot be contained statically by any known laboratory material, an adiabatic compressor was designed in which these extreme conditions of the
-Here's
gas could be obtained simultaneously for 1millisecondwithout permanent deformation of the container. With proper instrumentation, it would then be possible to measure dynamically the properties of interest. The present work is concentrated on studying the pressure-volumetemperature (P-V-T) relationship of gases a t these extreme conditions.
Although dynamic conditions solve some of the problems of gas containment, they increase many fold the problem of instrumentation. Work on the compressor has, therefore, had to be paralleled with development of precision instruments of very fast time response. Emphasis is placed on the over-all functioning of the instrumented compressor.
the Compressor and Instrumentation NOL adiabatic compressor and detail of high pressure end of compressor (bottom)
4
END PLUG Contains recesses for piezoelectric pressure g a g e (7) consisting o f a metal membrane to the back o f which a thin x-cut quartz crystal i s cemented, and either another window or a probe for determining the rest position o f the piston after the shot. The gage i s mounted beneath 0.005-inch steel plate so that pressure i s applied only to g a g e face. Rotating drum camera records last "4 inch of piston stroke. Clearance between end plug and piston is measured to 1 0 . 0 0 1 5 inch with exposure time o f 1.5 psec.
PISTON Weight 1 7 pounds; length 8 inches. Two rings each contain 4 grooves l/,e inch deep. Radial clearance a t largest ring diameter is 0.0003 inch. largest diameter o f piston is a t rings, because in event o f jamming, soft phosphor bronze will yield without damaging harder steel cylinder. The carriage is mounted on b o l l bearings and carefully leveled so that the compressor (1 600 pounds) can b e moved with a force o f only 5 pounds.
INSTRUMENTATION Electronic circuits (4,6 ) used to get synchronized timing markers and to control the general monitoring system. LOW PRESSURE END 2.2-cubic-foot reservoir for the driving gas; piston seat; release r o d mechanism for freeing piston from its seat a t tiring. Gas pressure remains constant within 5% of initial value. With piston in seat, reservoir gas i s sealed off from test gas b y 0ring in cylinder wall. CYLINDER Inside diameter, 3 inches; length, 3 0 inches; made from modified 4 3 4 0 steel heat treated to a yield strength of 178,000 p.s.i. and tensile strength o f 188,000 p.s.i. High pressure end reinforced b y a shrunk-on metal collar. Two assemblies are mounted in closed end o f cylinder-side window assembly and the end plug which makes cylinder a closed gun. End plug is continuously in view through fused silica side window. Piston i s seated with compressed gas coming through inlet 2'/3 inches from closed end.
VOL. 49, NO. 12
DECEMBER 1957
1987
At the time this investigation was started, no similar work had been described. Subsequently Ryabinin ( 7 5 ) reported a much smaller adiabatic compressor and Sage and Longwell (3) reported development of a much larger compressor than the present one. Although the principle of operation is comparable in each case, the objectives and instrumentation differ. The Naval Ordnance Laboratory compressor is the only one specifically equipped for study of equation of state relationships. Operation of Compressor
Equations predicting the behavior of the compressor and of the compressed gas may be obtained by assuming: 1. The reservoir pressure, P,,remains contant. (P, decreases to about 95% of its initial value during the first compression stroke.) 2. There are no frictional forces between the piston and the cylinder. (The measured force is less than 5 pounds -i.e., 1 pound per square inch in pressure differential.) 3. The gas is ideal, and compression is isentropic with no heat transfer to the wall and no leakage of gas. Equation of motion for the piston is M2 =
(P. - P , ) A
(1)
where hf = piston mass
A = piston face area P = pressure x = distance piston has traveled c (subscript) refers to compressed gas in cylinder
An ideal, isentropic compression is P,V,Y
where
= P*V'?Y
(2)
Y
= volume of gas = ratio of heat capacities C,/C, o (subscript) refers to initial conditions of gas
Equating the work done on the piston to the work done on the gas, and using Equation 2, gives
Equation 3 is particularly useful in predicting final values of P, and Ye from known values of P, and Po. Equations 1 and 2 can be used to obtain time as a function of a where a = x/stroke length. However, this involves a numerical or graphical integration for each specific set of conditions (Po,P,,y). Two further assumptions: 4. -4ssume Pc constant and equal to Po for the first part of the compression stroke.
-1988
Assume P, negligible compared P, at end of compression stroke.
5. to
Using these assumptions, Edwards ( 6 ) developed a simple method of estimating the time necessary for the piston to come into view at the side window and of evaluating P-time and V-time curves for sets of values P,,y, and Po. Table I summarizes the computed stroke times as a function of maximum pressure, P,, for an ideal diatomic gas with Po of 14.7 pounds per square inch; it shows that in the range studied the compression stroke will require 25 to 54 msec. Table I1 shows that the duration of the maximum pressure will be 25 to 500 psec., depending on the size of P,. (In general, duration is also strongly dependent on ?.) These data also show good agreement between predicted and measured durations, except for the lowest value of P,,,, where assumption 5 is least valid. These values have been tabulated to demonstrate the rapidity of the compression and thus indicate the need for the fast response instrumentation described. The rapidity also justifies, in part, the assumption of adiabatic compression, as little time is available for transfer of heat from the gas to the walls. Finally the data also show that the quantitative measurements carried out up to 30,000 pounds per square inch are of the same magnitude in speed as those to be made at 100,000 pounds per square inch. For operation of the compressor, both the reservoir and cylinder are filled with the same gas. Relations derived from Equation 3 give an approximate P, to use for whatever maximum pressure is desired at the end of the compression stroke, This estimate gives an order of magnitude for P-; the value obtained from the analytical expressions is low because of leakage and frictional effects. Estimates obtained from the equation of motion are used to set delay times, SO that recording of clearance and pressure will start when the piston reaches the side window. Equations 3 and 2 can be used to show that most of the pressure increase will take place after the piston is in view through the side window-in fact, the greatest pressure rise will be at the very end of the stroke. Figure 1 shows the actual pressure-distance curve for one of the runs at 30,000 pounds per square inch on nitrogen. I n this case, Po = 14.7 pounds per square inch and P, = 314.6 pounds per square inch. The piston stroke was 21.3 inches and, upon release, the piston traveled about 19 inches before the pressure differential was zero. At this point the piston acceleration is zero, but its velocity is still positive. I t continues to decelerate to zero velocity a t 21.26 inches, and then begins its expansion stroke. It oscillates back and forth several times before it comes to rest, but only the first compression and expansion are recorded.
INDUSTRIAL AND ENGINEERING CHEMISTRY
Experimental Records and Data Reduction
Figure 2 shows a piezoelectric gage output-time record; it has four equally spaced, horizontal calibration lines corresponding to known pressure values, and the record is interrupted for 2 psec. at intervals of 40 fisec. Figure 3 shows the corresponding clearance-time record ; the timing pips run along the bottom just below the image of the nearly stationary edge of the end plug. The punch marks at either end of the record, in con.junction with a second film recording magnification, give the calibration for the clearance measurements. Both records are for nitrogen compressed from 14.7 to 9300 pounds per square inch. They are adequate records, but both must be interpreted to obtain P-time and V-time variations. In general, three shots were made for each set of conditions. The records were read to obtain sets of P-t and V-i values. The corresponding pairs of P-V values were then plotted on a large scale log-log graph, smoothed, and corrected by very small amounts to the standard isentrope (25' C., 14.7 pounds per square inch) chosen for this work. The replicate runs were then averaged to give a single log-log curve. The standard deviation of all points from the average curve was less than 1yo; the maximum deviation, less than 1.5%. Figure 4 shows the upper part of replicate curves at the end of the compression stroke and the beginning of the expansion. I t is easy to show that the maximum pressure, P,, is more sensitive to the reservoir pressure, P?,than is the Bourdon gage used to measure this pressure. For this reason, P, was not expected to be well reproduced. As P, is not well reproduced, neither is the expansion stroke. Figure 4 shows that as P, is approached, the log P-log V curve shows appreciable curvature. This occurs at a time when the piston is slowing down and the pressure increasing; the combined factors of longer time and higher pressure can markedly increase gas leakage around the piston, and possibly heat leakage from the hot gas to the cylinder walls. (Mass leakage out of the cylinder and heat transfer to the walls have the same qualitative effect on the measured gas volume. Both effects are included in the term "leakage out.") Thus the location of the expansion isentrope varies with the net leakage at P,. For these reasons, data have been retained only for that portion of the compression stroke showing good reproducibility. Figure 5 shows typical scatter of the data points about a curve representing the average of four runs. Although the piston has a radial clearance of only 0.0003 inch with the cvlinder walls, and has grooved rings to reduce leakage, Figure 4 indicates a major
HIGH PRESSURE Table I. Variation of Computed Stroke Time with Maximum Pressure for y = 1.4 Nominal Stroke Time, Max. Pressure, Lb./Sq. Inch Msec. 3,000 10,000 30,000 100,000
46-54 37-40 29-31 25-26
2 8 1 0 0 0 /
= 24,000 v)
a
v
3
I
20,000
g
12,000
3
cn
8
Table II. Predicted and Measured Durations of Maximum Pressure Nominal Predicted Actual Measured DuraMax. DuraMax. Pressure", tionb, Pressurec, tionb, Lb./Sq. Inch Msec. Lb./Sq. Inch psec.
K Q
8,000 4,000
0
2,680 720 3,000 500 184 178 9,330 10,000 30,000 70 28,100 72 100,000 25 P o = 14.7lb./sq. inch, y = 1.4. P o 5 0.95 P,. Po atmospheric, gas NP.
...
*
L
5
IO
15
20
25
DISTANCE TRAVELLED BY PISTON (INCHES)
...
effect due to leakage out. Other evidence abounds that leakage is a major problem in the present design. Kennedy (8) has measured isobaric and isothermal P-V-T data for carbon dioxide u p to 1000° C. and about 20,000 pounds per square inch. These were used to obtain the isentropic data (77, 72) necessary for the compressor calibration. I t was then possible to compare the measured volume to the isentropic volume, V,, which would have been obtained a t a specified pressure if no leakage had occurred. The curve a t the left of Figure 6 shows such a leakage curve for the carbon dioxide runs at 3000 pounds per square inch; apparent fraction of initial load is plotted against gas pressure along the compression path. As this curve extrapolates to about 1.10 a t the loading pressure of 14.7 pounds per square inch, there has evidently been appreciable leakage from the reservoir into the cylinder during the initial lowpressure, long-time portion of the stroke as well as the leakage out mentioned earlier. As the same gas was used in both the reservoir and the cylinder, no complication arises from the mixing of two different gases. However, the gas entering from the reservoir is at a different temperature and pressure (different entropy) from the gas in the cylinder. Consequently, as long as mass leakage in occurs, the assumption of isentropic compression is invalid to a n indeterminant extent. The treatment of the carbon dioxide data shows the net effect of leakage in (mass) and leakage out (mass and heat). Leakage is determined not only by the pressure, but also by the stroke time. There is, therefore, a different curve for
r
16,000 iL U I
Figure 1 . Initial conditions:
Nz
Variation of pressure with piston position at 14.7 Ib./rq. inch
each set of initial conditions. Figure 6 shows the three curves for the shots at 3000, 10,000, and 30,000 pounds per square inch. While a net leakage of 25% is indicated at the highest pressure, the net leakage a t a given Po is lowered as the compression rate is increased. Table I11 summarizes measurements made with the free piston; they demonstrate how space and time are running out a t the higher pressures because of the high compression ratio. Measured isentropic Data for Nitrogen
Free Piston Data. Isobaric and isothermal static P-V-T data for nitrogen are available to 100 atm. and by some extrapolation to 3000' K. (70). From these, data for the standard isentrope were computed (73) and extrapolated from 1470 pounds per square inch to 2700 pounds per square inch. The isentropic data were then used to construct a leakage curve for nitrogen in the
Figure 2.
and 25' C., Pr = 314.6 Ib./sq. inch
lowest pressure range. Within the present experimental precision, the nitrogen leakage was the same as the carbon dioxide leakage at the same pressure on Constrokes resulting in the same P,. sequently the carbon dioxide leakage curves were used to correct the nitrogen data up to 25,000 pounds per square inch. The resultant nitrogen data were then converted to a common mass for the three experimental runges. These preliminary isentropic P-V values for nitrogen are shown in Figure 7, which also includes (dashed curve) the extrapolated low pressure nitrogen data. The overlap between the ranges is good (1 to 3% in volume), and part of the discontinuity can be attributed to the less satisfactory operation of the pressure gage in the lower pressure range. Data Obtained with Piston Modified to Carry Teflon Seals. To eliminate leakage in and minimize leakage out, the piston was modified to carry two Teflon cup seals mounted behind the second phosphor bronze piston ring (Figure 8).
Pressure-time record for nitrogen shot to 9300 pounds per square inch VOL. 49, NO. 12
DECEMBER 1957
1989
Table 111.
Summary of Shot Data Time,
Max. Interval Min. Pressure, 0.5 Pn t o P,,, Clearance, Lb./Sq. Inch psec. Inch Nitrogen 2,630 9,300 28,000
1,460a 416 157
0.442 0.131 0.075
Carbon Dioxide 2,630 9,300 26,800
Figure 3. Clearance-time record for nitrogen shot to 9300 pounds per square inch a
This modification increased the Gictional force from 5 to 21 pounds, but reduced the static leakage 100 fold. I t has no effect on the total time of the stroke or on the duration of the maximum pressure for the same final P,, and it required an increase of only 14 pounds per square inch (or less) in the reservoir pressure to attain the same P,. Evidently the seals did eliminate the leakage in, for the 3000-pounds-persquare-inch range leakage curve now extrapolates to about 0.98 instead of to 1.10. The measured data on carbon dioxide and nitrogen are given in Tables V and VI. The carbon dioxide data have been used, just as were the free piston data, to construct leakage curves. These, in turn, were used to obtain isentropic P-V data from the values measured on nitrogen. The improvement in the calibration treatment resulted in increased precision; it was no longer possible to draw three separate curves for the three repli-
Table IV Vol., Pressure, Cu. Inches/ Lb./Sq. Inch Mole 1500 1600 1700 1800 1900 2000
54.1 51.7 49.5 47.6 45.9 44.3
2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000
41.5 39.0 36.9 35.0 33.4 31.9 30.6 29.3 28.3 27.3 26.3 25.5 24.7 24.0 23.3
1,200 316 118
0.273 0.036 0.022
Record data extrapolated.
Final Dynamic P-V Data for Nitrogen Vol., Vol., Pressure, Cu. Inches/ Pressure, Cu. Inches/ Mole Lb./Sq. Inch Lb./Sq. Inch Mole 5,500 6,000 6,500 7,000 7,500 8,000 8,500 9,000 9,500 10,000
21.8 20.5 19.3 18.4 17.5 16.7 16.0 15.4 14.8 14.3
11,000 12,000 13,000 14,000 15,000 16,000 17,000 18,000 19,000 20,000 21,000
13.3 12.5 11.8 11.2 10.7 10.2 9.76 9.38 9.02 8.69 8.39
Figure 4.
22,000 23,000 24,000 25,000
8.12 7.86 7.64 7.41
Nitrogen data from compressor at end of stroke
1 Figure 5.
Scatter data of points about average curve
k
SOLID LINE AVERAGE OF RUNS 66-69
40i 3.38t-
n
g 3.20; J
I
e\&-
3.10'
3 3 4 1 0.50
1990
I
I
0 52
054
LOG
V
INDUSTRIAL AND ENGINEERING CHEMISTRY
I
3000.34 0.56
034
0.40 0.40
I-..-L----..-i 1
0 50 0.50
LOG v
06 0
0.70
-
4 4-
I
I
I
125,000
co2 *
3,000 PSI RUNS
4 2-
' 10,000 PSI RUNS O
I
30,000 PSI RUNS
t
-
40-
-10,000 - v) a
I
n
3 8-
n W
a
c?
3
v)
336-
W
a -3,000 a 3 4-
DATA FROM REF (13)
3 2-
a
0
5,802
11,603 PRESSURE tPSl)
17,405
*
Figure 7.
tropes. They will be even shorter at higher pressures and temperatures and no energy adjustment lag is expected to affect the temperature measurements. The perfect gas law can be used in conjunction with Equations 1 and 3 to obtain a qualitative view of the variation of temperature along the isentropes. Its behavior, of course, roughly parallels that of the pressure. Nominal temperatures obtained in the free piston shots were 1500°, 1770°, and 2600' K. for nitrogen, and 825', 1057', and 1300' K. for carbon dioxide. These are computed for y = 1.4 and 1.244, respectively. I n the case of carbon dioxide the estimate is about 75' too high at 20,305 pounds per square inch, the limit of the static P-V-T data. I n these lower pressure regions, the compressor is not instrumented for temperature measurement. When optical measurements can be made at higher pressures, it is hoped that the intermediate region between the static and the dynamic measurements can be bridged by interpolation. I t is expected that the gases a t high density (0.7 gram per cc. for nitrogen) and high temperature will behave as solid or liquid radiators, and exhibit a
,PHOSPHOR-BRONZE SOLlO PISTON RINGS%
'
,JlOOO
Preliminary P-V data for nitrogen
continuous spectrum in the visible region. This view was supported by obtaining an integrated-Le., not time resolved-continuous spectrum in test firings on nitrogen to 60,000 pounds per square inch. Subsequently, Russian workers (76) reported visible radiation from highly compressed gases. However, no such radiation has been observed at the Naval Ordnance Laboratory for nitrogen a t pressures up to 30,000 pounds per square inch. I t is planned to measure P-V data on argon u p to 25,000 pounds per square inch, and then to study gas radiation a t higher pressures. Compressor Data Obtained with Modified Piston
Raw data (Tables V and VI) were obtained from the compressor for three shots in each of the three ranges. Averaging and smoothing of the curves from replicate shots were unnecessary, as the curves were coincident. Hence their accuracy depends upon that of the measured pressure, clearance, and degree of synchronization of the timing markers on the two records. At present, the esti-
TEFLON CUP-TYPE SEAL PlSTOy HEAD
I 15
I
05
Figure 6. Leakage-pressure curves for carbon dioxide runs
cate shots, as each shot gave the same curve on the large scale plot used in the preliminary work. The 3000-poundsper-square-inch range data lay within less than 1% of the extrapolated static low pressure data, and its join to the 10,000-pound range was about 1.5% in volume. The join between the two higher pressure ranges (overlap area), was 2.7 to 0% in volume. Table IV contains data read a t various even values of pressure from the continuous curve for the range 1500 to 25,000 pounds per square inch. The specific volume for this tabulation is cubic inches per mole. These P-V data should vary from isentropic data only to the extent that the two gases might exhibit different heat transfer to the walls in the short time intervals indicated in Table I11 and might differ in mass leakage a t their different viscosities. (These two effects could, in part, cancel each other, since at the same P, both the temperature and the viscosity of nitrogen are higher than those of carbon dioxide.) T h e proximity of the experimental curves for nitrogen to the extrapolated low pressure isentrope indicates that its behavior up to 25,000 pounds per square inch along the isentrope is remarkably similar to its low pressure behavior, and that the net departure from isentropic behavior may be small.
\
23,206
O-RING
/
ADAPTOR
PISTON TAILSTOCK
Temperature Measurement
The maximum piston velocity is expected to be about 200 feet per second; under this operating condition, no shock will be generated in the compressed gas and no shock pressure has been observed on firings u p to 30,000 pounds per square inch. The vibrational relaxation times for carbon dioxide and nitrogen are, from extrapolated shock tube measurements, about 1 psec. a t 1000 and 3000 pounds per square inch on the isen-
Figure 8.
Piston with Teflon seals VOL. 49, NO. 12
DECEMBER 1957
1991
~~
V.
Table
Time Pip, No.
Raw Data Dioxide
for
Pressure, T,b./Sq. Inch
Carbon Vol.,
Cu. Inches
Run at 3000 Lb./Sq. Inch = 757 mm. Hg. to = 23.8' C. Voa 144.9 cu. inches. V d = 0.136 cu. inch. P7 = 132.0 lb./sq. inch. P , = 3,158 lb./sq. inch. urnb= 0.198 inch
Po
12 13
32 34 36 37 39 41 43 45 47 49
852 884 943 1078 1163 1252 1343 1401 1575 1703 1769 1925 2078 2172 2347 2527 2695 2860 2998 3099
51
3151
53
3154
15 19 21 23 25 26 29 31
5.219 5.081 4.801 4.261 3.998 3.756 3.512 3.391 3.057 2.845 2.748 2.545 2.368 2.280 2.125 1.978 1.859 1.756 1.665 1.603 1.557 1.531
Run at 10,000 Lb./Sq. Inch = 741 mm. Hg. to = 23.9' C. VO' = 144.9 cu. inches. Vd = 0.136 cu. inch. Pr = 175.6 lb./sq. inch. P , = 9,475 lb./sq. inch. urn6 = 0.065 inch
Po
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
2209 2398 2613 2866 3142 3468 3866 4286 4846 5454 6117 6890 7665 8440 9046 9394 9473 9440 9130
2.301 2.147 1.985 1.826 1.681 1.545 1.401 1.278 1.162 1.039 0.943 0.859 0.782 0.716 0.660 0.630 0.609 0.596 0.611
Run at 25,000 Lb./Sq. Inch P o = 749 mm. Hg.
25.0' C. VO"= 145.3 cu. inches. V d = 0.130 cu. inches. Pr = 233.0 lb./sq. inch. P, = 27,850 lb./sq. inch. ymb 0.017 inch 15 15.5 16 16.5 17 17.5 18 18.5 19 19.5 20 20.5 21 21.5 22 22.5 23
"
to =
4472 4917 5479 6040 6797 7653 8795 10083 11824 13731 16442 19343 22614 25413 27078 27891 27065
Initial volume of cylinder.
1.410 1.304 1.206 1.111 1.012 0.918 0.828 0.742 0.661 0.581 0.513 0.450 0.397 0.352 0.323 0.298 0.276
* Minimum separation end plug to piston.
mated accuracy of the pressure measurement is within + l % ; and of clearance, 10.001 5 inch. Any error in synchronization is considered negligibly small. While the initial temperature and pressure of the test gas, in general, differed from the values of 25' C. and 760 mm. of mercury adopted for the standard isentrope, all replicates in this series were shot a t the same P, and t o . Consequently, the values for one shot are typical of the group, and only one operation was necessary to correct each group to the standard isentrope. This correction is made on the volume and is small; detaiIs of the treatment have been given (9, 7 4 ) . For the raw data in Tables V and VI, volume V has been presented for convenience rather than the measured clearance, y . T h e relationship is simply
where V , is the dead space volume computed from micrometer measurement of the compressor parts. No correction was made for any change of Vdwith pressure. Acknowledgment
Many people have worked upon this project and its progress is the result of the group effort of these NOL staff members. Specific mention should be made of the work of P. 1,. Edwards, who designed the piezoelectric gage and the electronic circuitry, and of R. S. Allgaier, who designed the high speed streak and spectrographic cameras. References ( 1 ) Allgaier, R. S., Naval Ordnance Laboratorv. ReDt. 3555 (1953). . , ( 2 ) Ibid., 3848 (1'953).' (3) Chem. Eng. News 34, 1446 (1956). (4) Edwards, P. L., Instr. and Automation 30, 1504-6 (1957). ( 5 ) Edwards, P. L., Naval Ordnance Laboratorv. ReDt. 2880 (1953). Ihid.,3754 (1954); PB 122;050. ' I . . 3559 (1955). iy, G. C., A m . J . Sci. 252, 1954). T., Naval Ordnance (9) Laboratory, Rept. 4202 (1956). 110) Natl. Bur. Standards (U. S.). Circ. 564 (1955'1. Price, 'D., 'IND. ENG. CHEX 47, 1649-52 (1955). Price, D., 1x0. ENG. CHEX, CHEM. ENG.DATASERIES1, 83-6 (1956). Price, D.. Lalos, G. T., Naval Ordnance Laboratory, Rept. 3964 (1955). Price, D., Lalos, G. T., Edwards, P. L., Allgaier, R. S., Zbid., 3990 (1955). Ryabinin, Yu. N., Zhur. Eksptl. E Teoret. Fiz. 23, 461-7 (1952). Ryabinin, Yu. N., Sobelev, N. N., Markevich, A. M., Tamm, I. I., Zbid., 23, 564-75 (1952). ,
I
I
Table VI.
Time Pip, No.
INDUSTRIAL AND ENGINEERING CHEMISTRY
Pressure,
Lb./Sq. Inch
Volume,
Cu. Inches
Run at 3000 Lb./Sq. Inch
21 23 25 27 29 31 33 35 37 39 41 43 44 47 49 51 53 55
1392 1496 1597
1722 1846 1981 2132 2284 2441 2598 2747 2887 2950 3112 3184 3218 3220 3185
5.003 4.731 4.466 4.217 3.978 3.755 3.545 3,344 3.167 3.001 2.850 2.724 2.661 2.522 2.457 2.420 2.404 2.389
Run at 10,000 Lb./Sq. Inch 748 mm. Hg. to = 23.0' C. VO"== 144.9 cu. inches. Vd = 0.136 cu. inch. P, = 220.5 Ib./sq. inch. P, = 9,670 lb./sq. inch. urnb= 0.114 inch.
Po
=
11,
2156 2318 2507 2688 2930 3201 3534 3841 4216 4651 5143 5687 6256 6909 7538 8176 8747 9208 9513 9673 9572
12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
3.588 3.391 3.186 2.992 2.799 2.619 2.437 2.263 2.099 1.941 1.788 1.648 1.512 1,396 1.287 1.191 1.112 1.046 0.980 0.950 0.940
Run at 25,000 Lb./Sq. Inch Po = 749 mm. Hg. 1, = 24.5' C.
Vo" =
146.3 cu. inches. vd = 0.130 cu. inch. P1 = 320.5 lb./sq. inch. P , = 26,990 lb./sq. inch. urnb = 0.033 inch 16
17 17.5 18 18.5 19 19.5 20 20.5 21 21.5 22 22.5 23 23.5 24 24.5 25
,
RECEIVED for review May 11, 1957 ACCEPTED August 21, 1957 Division of Industrial and Engineering Chemistry, High Pressure Symposium, 131st Meeting, ACS, Miami, Fla., April
Raw Data for Nitrogen
Po = 757 mm. Hg. to = 24.0' C. V," = 144.9 cu. inches. Va = 0.136 cu. inch.. P , = 154.7 lb./sq. inch. Pm= 3220 lb./sq. inch. urnb= 0.321 inch
'
1957.
1992
~~
0
b
4739 5610 6113 6769 7434 8270 9250 10356 11669 13259 15043 17082 19351 21693 23924 25707 26784 26961
2.124 1.854 1.729 1.605 1.484 1.370 1.252 1.133
1.029 0.933 0.837 0.755 0.677 0.602 0.534 0.475 0 436 0.403 I
Initial volume of cylinder. Minimum separation end plug t o piston.
