6%2e1966-680
DESCRIPTION
66TRANSCRIPT
IGNITER PERFORMANCE IN SOLID PROPELLANT ROCKET MOTORS
by
DAVID M. ADAMS Thiokol C h e m i c a l Corpora t ion Huntsville, Alabama
AIAA P a p e r No. 66-680
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IGNITER PERFORMANCE I N SOLID PROPELLANT ROCKET MOTORS
DAVID M. ADAMS, Senior Engineer Engineering Research Section Thiokol Chemical Corporation
Huntsville, Alabama
ABSTRACT
Analytical predictions for the effect of mass discharge rate from , single or multiple pellet mode pyrotechnic igniter elements. operating in-,
dividually or in Pyrogen igniters, on chamber pressure transients in inert
chambers and during the ignition phase of solid propellant rocket motors , are presented. Pellet geometries considered were cylindrical, short ova!,,
long oval, spherical, and rectangular. Flame spread delay. erosive burn-
ing and pressurization rate effects on propellant burning rates, and mixing
of igniter gases (multiple mode pellets) with motor gases generated were
included. Comparison of several of the predictions to corresponding ex-
perimental pressure-time histories showed reasonable agreement. Signi-
ficant information was obtained in regards to the cause of ignition pressure
spikes (erosive burning or igniter mass discharge rate) and the requirements
for proper igniter size and type to yield satisfactory motor ignition.
INTRODUCTION
In order to properly design an ignition system for solid propellant
rocket motors requiring pyrotechnic pellet type igniters and/or Pyrogen
igniters. the effects of igniter mass discharge rate on the chamber pressure
transients in inert motor chambers and during the ignition phase of solid
propellant rocket motors must be known. To predict these effects. the
governing equations for the ignition element. motor chamber. and motor
discharge nozzle were coupled and solved by numerical methods on an
IBM 7094 computer.
The analysis considered multiple pellet mode pyrotechnic ignition
elements (cylindrical, short oval. long oval. spherical. and rectangular
psllcta) andlor Pyrogen ignition elemants (my propellant grain configuration)
that operate
bnts of any grain configuration.
of ammonium perchlorate oxidizer mixed with a hydrocarbon fuel binder.
Pellet composition w a s Boron-Potassium Nitrate (excluudlng rectangular
pellets).
effects on the propellant burning rate were included.
gas mixture (multiple mode pellets) and motor gases generated were coosidcr-
ed to determine the equivalent characteristic velocity. c*, and specific
heat ratio. y. during the ignition phase. Nonequilibrium effect8 in t h e igni-
tion element and heat transfer to the motor propellant surface were neglected.
To teet the validity of the analytical solutions, the results were compared to
experimental pressure-time histories for various igniter and igniter-motor
conditions.
in inert motor chambers or in motorm with cmnpo8ite propsl-
Componite propelknts utilized coneisted
Flame spread d e b y and erosive burning and pressurization rate
Mixing of the igniter
The analyeis and results given herein summarise work done previously
by the author1*.
tensively for the present applications, wa6 supplied by BallardZ.
tal data (burning rates, f b m e spread delays, pellet geometries, and preesure-
time curves) were obtained from R. E. Overall3.
The original computer program. which wae modified ex-
Experimen-
*Superscripted numbers refer to references at the end of the text
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ANALYSIS The mass flow rate through the nozzle can be derived a8 follows:
m ni . = A.V.0. 1 I I Continuity (3)
A schematic diagram of the igniter (pyrotechnic andlor Pyrogen) geo- To express V,,p, in terms of h o w quantities,
re 1. The following assumptions for the igniter per-
1. Mass rate of accumulation m . in igniter combustion chamber El
1-1
Isentropic (4) Relations
neglected. c82 E Ri Tci , and Characteristic
2. One-dimensional steady adiabatic flow. i-2 Velocity
3. Burning surfaces of pellets (or Pyrogen propalbt) , A ignite
i
spi'
instantaneously.
No variations in chamber pressure, P ., and temperature.
along grain (or pellets). CI
r i 2 = Yi p-j I-) 4. T . Yi + 1
I h . Energy Equation (5) 1 2
c1 C1'
Then, hi + Vi
hi 5 . Burning rate r E a. (Pci) n. I . where, = c . T . Enthalpy,
6. Ri, and = (3 y - 1
bi z c . P' Isentropic nozzle, irreversibilities reflected in the uBe of actual
2 2 characteristic velocities c*. . Ri 'ci = COi Ti
7. Exit pressure of nozzle Pei equals motor chamber pressure P?. T h U S ,
8.
9.
Combustion gases act as ideal gases.
Single or multiple pellet modes. [' -(&) y . - 1
"I Analytical Relations --Igniter
For combustion gases acting as ideal gases. 1 P . For steady one-dimensional flow of a singlegas, mass flow generated. pci oCi E- =
Ri 'ci equals m a s s flow through the nozzle, m _. or ni Substituting the expressions for V. and 0 back into Equation (3) gives: yi = m . . ni (1)
The mass flow generated in the igniter is given by:
%i = ppiASpirbi = $iAspiai(Pci)ni. (2)
Ai pci m . = A.V.0. = - ni 1 1 1 C*. 4
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E n u r u p g Equations ( 2 ) and (6) gives:
AiPci4 C *i
p . A .a ( q i l n i = p1 llp1 i
For multiple pellet modes, the total mass generated i s the s u m of the m a a n
gomerated by each type of pellet (or Pyrogen propellant) in the igniter.
tion ( 8 ) becomes:
E q u -
5 p A .a . (p - AiPci4e ] C*ie pi BPI 1 c1 L I (8 ' )
where up to five different gases m a y be considered. Refer to Page 7 for the
equations of the equivalent c* , and y. for the mixture of gases. le le
The two conditione examined further were choked flow and unchokcd
flow.
Choked Flow
For choked flow (aonic flow at throat of nozzle) the equilibrium pres-
in the igniter may be found by evaluting Equt ion (8 ) at the throat sure P
of the igniter. l n u s .
c i
where Bti = 1 at the throat.
Equation (9) involves only one b o w . Pci, 1 -
c1 where
5
For multiple pellet modes. Equation (9) becomes:
L k = l
Jk
Shce Pci is not given explicitly a s in Equation (9). it was determined by
iteration. Then.
5
~ p i A s p i a i ( P c $ n ~ (single or multi- (11) PIS pellet mode.) "'nti = mbi
k = l
n e above Equation (11) is only valid when the back pressure (Pc - motor
chamber pressure) is less than that required to produce mbsonic flow in
tbe throat. The critical pressure ratio (Pc/Pc$* is found an follows:
m = m or nei nti .
from Equation ( 6 ) .
pc < - Choked Flow
* If - pci - (2) pc > - UnchokedFlow
Unchoked Flow
From Equation (8 ) . svaluatcd at the e d t of tbc nozzle.
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an analysis of gaseous mixture equatioua, it may be shown that Yi t 1
the above equations yield satisfactory r e d s and that th
determining the equivalent values c * ~ ~ and yie a r e the
of the mixed gases.
t 2(n. - 1) 1 (I3) - (2) -T-
ed pellet modes. Equation (13) becomes:
To provide for various types of pellets in the igniter. the equations
used for the cylindrical, oval, spherical. and rectangukz pellets were:
Cylindrical 0 aD (+) [e) ($1) [ ( 2 ) K - (4 P i 4 (r D2W
( 1 - n i ) ) 2 l k
2
k = l
2 2 Volume of pellet V = -
+w+ Cylindrical Pellet
Equations (13) and (13'). like Egvation (12). involve one &own. wt
PclPci. Since P lPci appears explicitly in the equations, the equations C
.. Number of pellets N = 2 (same equation for all
P .v . pellet types) Pi P' P'
were progrsmmed for solution of P I P . by iteration. Then.
5 c c1 where Wti I Total mas8 of pellets,
= Density of pellets, and *Pi
(single or multiple m r nei - kpiAspiai(pc?] pellet modes) i - (14)
k s l k SurfaceareaofpelleteA
sei To account for mixing of the gases generated by each type of pellet (or
Pyrogen propellant), the equatiGns u s e d to approximnte the equivalent c* and
ecific heat ratio, y. were based on the m a s s flow rate percentage, c*, and
To determine the surface area of the pellets a s a fupction of time, t, during
igniter operation:
heat ratio of the individual gases. The equations a r e given as: D = D - 2 rbi t (20) (t = tl)
5
'!e k = l f .k*iyil / kzl [Yi] (15) = W ( t = t ) - 2 rbi t (ti = (21) 1
(2 Oval (short and long)
n D n h3 2
h V = - ( W - h ) t - k r l k = l Pi 4 3
(16) k
Yie
Oval Pellet
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A . I [ 4 I R h + n D ( W - Z h ) ] N . ( W ? Z h ) SPl P'
= [4 n Rhl Npi (W < 2h)
where h = R - R cos sin (W
Then. - D(t- tl) - 2 rbi t
- I t bi R = R (t = t,)
w = W ( t = t ) - 2 r t 1 bi
h = h o - r b i t ( W < Z h a t t = t ) 0
Spherical
n D3 v . = - P' 6
Spherical Pellet A I (.D'I N .
SPi P'
Then.
- 2 rbit - D(t = t,)
Rectangular
V . = (WHD) T I-(aLD +w+
T P'
Rectangular Peilet
A = 2 ( W H + W D t D H ) N . BPS P'
Then.
(32)
(33)
- 2 Ibit W(t = t,)
= H(t = t l )
w r
- 2 rbi t
- 2 r t bi D - D (t = tl)
Pyrog-
An input table w8s included in the program for the progan igniter that
considers the igniter surface and throat area variatione versus percent web
burned.
ra te or combined with the pyrotechnic igniter.
A8 mentioned earlier. the Pyrogen igniter may be considered s e p -
Finally. Equations (10) through (36) were programmed for solution on
an IBM 7094 computer.
motor d y e i s w8e the mass flow ra te frmn the igniter. Ti, obtained f rom
Equationa (11) and (14) for choked and unchoked cmditions, respectively.
All of the other equations were necessary to obtain the inputs to EqYraons
(11) and (14).
Motor Assumptions
The only value necessary for compUhtiWI. in the
A mhematic diagram of the motor geometry i n shown on Figure I . The
folloaring assumption. for the motor performance were mads:
1. One-dimensional steady adiabatic flow.
2 .
3. No variations in chamber pressure P and Temperature
Combustion h e spreads as a function of time.
C
T along the grain.
4. Burning rate r = a (Pc) . C
n
5 . Isentropic nozzle, irreversibilities reflected in the use of
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6 .
7.
8 .
9 .
The nozzle is always choked.
actual characteristic velocities c*.
Combustion gases plus igniter gases act as ideal gases.
W a l l f r ic t im along grain neglected.
Buming surface As = f ($ web burned).
- d 9 dt = - 7 [ c P C * 2 m - pc As a(Pc)J, but
- pc = R T 5 c * r 2 2 a n d p = - 9 2 2 =* r PC
(1W Thus.
fl (t. Pc, b) = - = Analytical Relations- - Motor dPC r 2 2 Asa(Pc)
vc VC (37) dt A brief review of the eqvatians given in Reference 2 is included to
acquaint the reader with the uses and lidtatiens of the analysis. In summary, where
tha. mass rate generated t mass rate from igniter I mass rate through
noazle t mass rate accumulated, or m c = p P S A t [@spiai(pcdni] -AtPC c* ' a n d
(38) k = l k
t m mb + mbi "n
(b-web thiclmase) n
(39) = dq) db
where % = P A a(p,kn, dt b f2 (t. Pc, b) = - = r
P S Variations in propellant surface area, A , motor chamber volume,
Vc. and nozzle throat area, At, were considered a function of percent web
AtPC m =- n c* '
burned and determined from the propellant grain configuration and nozzle 5
(from igniter equations), and
k k = l
or n Vc d P C Then, m = pcAs a(Pc) t - - 2 2 dt r C*
11
erosion tests. respectively.
To provide for corrections to c* of the motor chamber gases due to
mixing of the igniter mass discharge with the m s s generated in the motor,
the following equation was used.
where the subscript p refers to the separate Pyrogen igdter and RCSi i5 the
ratio between the actual c* Values of
RCS were obtained from the pressure-time curve for igniter ignition in an
inert motor chamber and values of c* were obtained from the pressure-time
and theoretical c*. for the igniter. ia 1
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I curve of the motor (neglecting effect of igniter).
To provide similar corrections to yof the motor chrmbar gases
*ring ignition. the follw7ing equation was U8.d:
(41)
Equations (40) and (41) are similar to Equations (15) m d (16) which
were utilized to determine the equivalent c fe and r,, in an igniter with mul-
tiple pellet modes.
To accoIlpt for h e s p r u d delay over the motor propellant surface.
an input tabl. WAS included in the program that considers the effective motor
b m d q llvrface area versus time. In addition, experimental pressure-time
data for the motor may be included in the table. In this case, the data a r e
rued t o calculate the motor surface area versum percent web burned varia-
tions required to duplicate the experimental input curve. Principal usee of
the latter inpts a r e in motor performance demign requirement. and for the
determination of h e spread functions rather than for the performance
mnlysis of motors.
Since axid grrin geometry variations were not considered in the
d y s i s , the equations to include erosive burpins and pressuriaatim rate
effects on rb must be regarded as approximate.
Aasuming a cylindrical port grain configuration. the variation in
port aru, A with percent web burned is given an: P'
A = A P Pi
13
2 = MUal port area averaged along the length of grain. in
2 Mprdmum port area averaged along motor casing. in
Percent of web, b. burned
Percent of web, b. burned at which A
u W y takmn at motor burnout).
=
occurs (% bm Pm
The Mach number at the wdt af tho port may be expressed implicitly
4 8.:
assuming tbat the motor nozzle is choked and that the flow is isentropic
between the port exit and motor nozzle throat.
reduced to:
The above equation may be
which is reasanably accurate for M
Since the Mach number at the head-end %e the average port Mach number is given as 2 = Me12.
7 0 . 6 . 1.1 < y <1.3. r n d A S A Pe P'
0 (neglecting igniter discharge).
To relate the dependency of the burning rate on the average Mach
5 number of the gages in the port, the follw7ing relatimship was util i!zd
Keb [e)m (43)
where K cb
Merit
= Erosive burning correction factor
= Critical Mach number below which no erosive burning
occurm
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m = Erosive burning exponent.
Typical values of M . and m utilized are: cri t
s with burning rates of rb gO.25 inlsec.
To for the dependency of the burning rate on the pressuriza-
tion rate. dP Idt. the following relationship was wed: 6 C
n atdPc/dtl K pr (1 '6' t0.572) (44)
where K r Pressurization rate correction factor pr
a .i propellant thermal dfftusivity (Klcp) - 2
in lsec
a 5 Uncorrected burning rate coefficient
n = Burning rate exponent.
The above equation may also be used to predict, approximately, the
depressurization rate, dPcldt. a t which propellant extinguishment ocfurs.
S e w KDr = 0 gives:
-[alp, (n*. d P C - (eXMnguiShment) r
M
ove correction factors, the burning rate equation
corrected for erosive burning and pressurization rate effects assumes the
form: .
Equations (37) through (45). in addition to the igniter equations given
C' earlier. were programmed for solution of the motor chamber pressure. P
and web thickness burned. b. as a functicm of time. t, utilizing the Run
Kuita finite differ technique. Other equations were incMed to ev
such values as instantaneous motor chamber volume, motor thrust. squill-
b r i m pressure (includhg igniter mass discharge). specific impulne, impulse,
pressure integral, and propellant consumed. Time intervals of integration
were automatically adjusted for accurate prediction of rapid transients and
pressure spikes.
RESULTS AND DISCUSSION
I Analyncal solutions were obtahedfor the followkg igniter and ignl-
ter-motor conditions:
1. Cylindrical. short oval. long oval, spherical, and rectangular ~
~
pellet igniter operation in inert motor chambers.
Multiple pellet mode igniter operatirm in an inert chamber and
in a motor.
3. Cylindrical pellet igniter operation in a Pyrogen igniter and com-
bined cylindrical pellet igniter and Pyrogen igniter operati- in
two types of rocket motors.
, 2.
1
I
The pressure-time histories for the above cages were compared to ~
1 corresponding experimental data. Comparisons between analytical solutions
and experknental data a r e shown on Figures 2 through 12.
above igniter aad igniter-motor conditions a r e summarized in Table I.
Data for the = a ' (pf K~~ K~~ b
2 1 <<I, = 1 when E 5 Merit and (nc! dPc/dt)l[ ='PC (nt0.5) Fipnos 2 through 7 give the analytical prr smrs-time curves for
cylindrical, short oval. long oval, spherical, rectangular, and multiple
where K I K
rerpactively . eb pr
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pellet mode pyrotechnic igniter operation in inert chambers, respectively.
Comparitxm to corresponding experimental data (with the exception of the
rectangular pellets. for which no data exists yet) is in good agreement and
the differences are well within experimental tcmt variations. Generally, the
lnolyHca1 predictions are higher during prcmurimation of the inert chcmbsr
since ignition delay of the pellets and nm-equilibrium effects in the igniter
were neglected. Burning rates given in Table I for the boron-potassium ni-
trate pellets (excluding rectangular) were dependent on preasure (rbi= aiPc i)
and different than the constant value of r
bar presaure,measured by Scheier' for cylindrical pellet tube type igniter
operation in inert. vented chambers.
n
I 1.5 inlsec, IrreBpective of cham- bi
J i is important to note that neglecting the effects of adjacent pellets
on the burning mechanism of individual pellets (as considered in the anrly-
sis) have not lead to serious e r ro r s in the predictions of chamber presaure
transiQtS.
where the pelleta a r e contained in a cylindrical tube and the generated gases
a r e exhausted through a number of vent holes in the casing of the tuba. The
spherical pallet igniter was 'bag type'. where the bag is ruptured during igni-
tion and the pellets burn in the motor chamber.
igniter i s the 'plats type', where the gases generated from contained pelleta
exbaust through a vented plate.
Zhe above igniters (except spherical pellet) were 'tube type'.
Another common type of
Figure 8 shows the analytical and experimental chamber pressure
transients for the above mentioned multiple pellet mode igniter operation in
a motor (conventional wagon wbeel grain configuration). The critical Mach
number. Merit, defined on page 13 w a s reduced to 0.115. Flame spread de-
lay over &e motor propellant surface area w a s considered a linear function
from .005 (beginning of ignition) to .04 Bec (complete ignition). To obtain
more accurate estimates of flame spread delays based on heat transfer cal-
cuktions to the motor propclknt surface rather tba% on experhsnta l obsar-
vationa. analytical d y s e s . such a n that presented by Wllmrn and Nielsen 8 ,
nhould be revtewed.
Analytical S O ~ U ~ ~ Q B were obtained for combined igniter-motor opsra-
tion with and witbout erosive burning and pressurization rate effects on mctor
propelknt burning rate. R o m Figure 8. it i n seen that the ignition spike
resulting from igniter m a s s discharge i s s m a l l and that the resultant igni-
tion spike corrected for erosive burning effects (pressurization rate effects
were small) agrees well with the experimental curve.
Figure 9 &OWB the chamber pressure transients for cylindrical pellet
plate type igniter operation in a Pyrogen igniter where the Pyrogen igniter
was coneidered a s the motor (forked wagon wbeel grain configuration).
spread delay over the motor propellant surface area was considered a linear
function from .002 to .01 aec.
erosive burning effects (pressurization rate effects were small). agrees
reaeonably well with the experimental data. Again, the ignition spike due to
igniter mas11 discharge. disregarding erosive burning effects, is less prs-
dominant.
Flame
The predicted ignitian apike, which includes
The combined cylindrical pellet igniter and Pyrogen igniter discuaaed
above was used to ignite two different types of rocket motors, the analytical
predictions and correaponding experimental pressure-time hietoriea of
which a r e shown on Figures 10. 11, and 12 respectively. %e former mo- I
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tor utilized a standard starpoint grain configuration while the latter motor
had a cylindrical port grain configuration with two circumferential slots
located fore and aft along the grain. Plame spread delay over the motor
sidered linear from .Ob0 to .090 8ec for
Figures 10 and 11, and linear from 0 .O to .08 sec for the
e rocket motor in Figure 12. Figure 10 shows the pressure
time histories during the first 0.4 second
corresponding results for the eatire duration of motor firing. Predicted
ignition spikes agree well with the experimental data for both motors. lg-
nition spikes for both motors produced by igniter m a s s discharge a r e much
less predominant than the resultant ignition spikes corrected for erosive
burning effects.
of ignition while Figure I1 gives
The disagreements between predicted ignition spikes and experimen-
tal data just beyond the peak pressure may be partly attributed to the assump-
tion given previously that the port area increases nth percent web burned
as in a cylindrical port motor and to the neglect of aldal grain geometry
variations; i.e.. of the resultant variations in adal port areas, eurface
areas, static pressures. and static temperatures. Port areas in starpoint
or wagonwheel configurations increase more rapidly than in cylindrical
port configurations, tending to yield lower pressures bey- the ignition
spike.
CONCLUSIONS
1. Analytical non-equilibrium chamber pressure transients for py-
rotecbnic pellet type igniter and/or Pyrogen igniter operation in inert motor
chambers or during the igition phase of solid propellant rocket motors were
presented. Reasonable agreement was observed between analytical and
experknental pressure-time histories for the igniter and igniter-motors
conditions considered, a s seen from Figures 2 through 12.
2. Significant information was obtained in regards to the cause of
ignition spikes and the requirements for proper igniter size and type to yield
satisfactory motor ignition. Ignition spikes were caused primarily by ero-
sive burning effects on the propellant burning rates, rather than by igniter
mass discharge, as seen from Figures 8 through 12.
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REFERENCES NOMENCLATURE
1.
2.
3.
4.
5.
6.
7.
8.
Adams, D. M., "Analysis of Igniter Performance in Solid Propellant Rocket
Motors". Thiokol Chemical Corporation. Huntsville, Alabama, Special
Report No. U-65-373. Sept., 1965 (Addendum Memorandum, October. 1965).
Ballard. R. M., "Nonequilihrium Ballistic Performance Analysis for Solid
Propellant Rocket Motors". Thiokol Chemical Corporation. Elkton Report
RER-332, May. 1964.
Overall, R.E., Igniter Section, Tbiokol Chemical Corporation, Huntsville,
Alabama, Personal Communication.
Shapiro. A.H., "The Dynamics and Thermodynamics of Compressible
FluidFlow", Ronald Press Co.. New York, Vol. I. p. 86, 1953.
Saderholm. C.A., "A Characterization of Erosive Burning for Composite
H-Series Prapellante", ALAA Solid Propellant Rocket Conference, 1964.
Paul, B.E., Cohen. N.S., and Fong. L. Y., "Solid Propellant Burning
Rate Under Transient Heating and Extinguishment Via L t Instability",
Abstract, Aerojet-General Corporation. Sacramento. California, 1964.
Scheier. W. ."Pressure Transients for Boron-Potassium Nitrate Igniters
in Inert, Vented Chambers." JPL. Pasadena, California, TN Report No.
32-33, September. 1960.
Fullman. C.H., and Nielsen, F.B., "Theoretical and Experimental Inves-
tigation of Ignition Systems for Very Large Solid Propellant Motors",
UTC. Sunnyvale, California. Report RTD-TRD-63-10. May. 1963.
21
symbol
As
At
A SP
a
b
c*
Mc
h m
m
m
n
c
n
pc
pr
R
'b
Tc
v c
t
V P
Wt
r
Y
PP
Nozzle Exit Area
Burning Surface Area
Pellet Burning Surface Area
Nozzle Throat Area
Burning Rate Coefficient (a=* Ip )
Web Thickness of Propellant
Characteristic Velocity
Instantaneous Mass of Gas in Motor Chamber
Mass Rate Generated
M a s s Rate Accumulated
Mass Rate of Flow Through Noznle
Burning Rate Exponent
Chamber Pressure
Reference Pressure
Gas Constant
Burning Rate
Temperature of Combustion Gases
Time
Free Chamber Volume
Volume of Igniter Pellet
Propellant or Pellet Weight
Function of Y
Specific Heat Ratio
Propellant or Pellet Density
b r
22
2
2
2
2
in
in
in
in
in
ftlsec
lbm
lbmlsec
lbmlsec
lbmlsec
_ _ _ lbflin'
2 lhflin
ft 1bfllbmOR
in lsec
OR
sec
3 in
in3
lbm
-__ --_
3 lbmlin
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556'1
9F1
069
_ _ _ _ .. -.
..
..
..
.. -.
6'85
2 t 2 '
886
IOIt'
0925 .-
790'
~ l e p s n o ~ e r d ass L1.t
95'0
O'bt
(0'1.1
1188'
1288'
052'
051'
571'
F C O '
9 f t '
0001
t8. 0 1ov 0005
290'
1.1
252 '0
1'1
12'7
2520'
2 5 2 0 ~ .- _ _ .- -.
80' Eta'
55000' ESOOO- t61'
59 I
(('1
OZ62
Otlt
6F90'
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9t.91
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1188.
052 .
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257'
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69
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..
MOTOR CHAMBER 1.07 i.07 PROPELLANT EXHAUST NOZZLE 1 1.07 1.07 [PYROGEN IGNITER
21. b I10
FIGURE 1 SOUD PROPELLANT IGNITER-MOTOR CONFIGURATK*( ..
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-EXPERIMENTAL DATA
SEE TABLE I FOR INITIAL CONDITIONS AND DATA
a
0 .020 .040 .060 .080 " .ULW .wu .MU .080
I ---.ANALYTICAL I --EXPERIMENTAL DATA SEE TABLE I FOR INITIAL
t -TIME, SECOND FIGURE 2. CHAMBER PRESSURE TRANSIENTS FOR CYUNDRICAL PELLET FIGURE 3.CHAMBER PRESSURE TRANSIENT FOR SHORT OVAL PELLET
IGNITER OPERATION IN AN INERT CHAMBER IGNITER OPERATION IN AN INERT CHAMBER
i
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c
W a a
a a
a W
E 100.
4 I 0
u a 0
-EXPERIMENTAL DATA SEE TABLE I FOR INITIAL CONDITIONS AND DATA
-EXPERIMENTAL DATA SEE TA8LE I FOR INITIAL CONDITIONS AND DATA
L MO .oeo .OW 040
t -1IME.SECOND FIGURE 5. CHAMBER PRESSURE TWSIENTS FOR SPHERICAL PELLET
IGNITER OI'ERATIOFS IN AN INERT CHAMBER Dow
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FIGURE 6. CHAMBER PRESSURE TRANSIENT FOR RECTANGULAR PELLET IGNITER OPERATION IN AN INERT CHAMBER
i
-EXPERIMENTAL DATA CYUNDRICAL, SHORT OVAL, AND LONG OVAL PEUETS SEE TABLE I FOR INITIAL CONDITIONS AND DATA
t-TIME ,SECOND FIGURE 7. CHAMBER PRESSURE TRANSIENTS FOR MULTI
PELLET IGNITER OPERATION IN AN INERT C
i !
i 1
i
j I
j
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IGNITION SPIKE PRODUCED BY /IGNITER AND EROSIVE BURNING
.I c ---ANALYTICAL ~-IANALYTICAL-EROS~VE BURNING AND
- . PRESSURIZATION R A E COR
w -EXPERIMENTAL DATA
a a W L’
3 SEE TABLE I FOR INITIAL
SO0 z a m w
2 3 P I . . . On I 2 3
\ 4 5 6 7 - - -
1- TIME, SECOND FIGURES. CHAMBER PRESSURE TRANSIENTS FOR MODE
PELLET IGNITER OPERATION IN A MOTOR
IGNITION SPIKE PRODUCED BY IGNITER AND EROSIVE BURNING
-EXPERIMENTAL DATA SEE TABLE I FOR INITIAL CONDITIONS AND DATA
IGNNITION SPIKE PRODUCED BY IONlTER
PYROBEN IQNITER CONSIMRED As MOTOR
c 0 at 02 0.3 0.4
t- TIME,SECOND
FIGURES. CHAMBER PRESSURE TRAWENTS FOR CYLINDRICAL PELLET IGNITER OPERATION IX A PYROQEN BNtlER
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I
I
I I
~
IGNITION SPIKE PRODUCED BY IGNITER AND EROSIVE BURNING
IGNITION SPIKE PRODUCED BY IGNITER
W I FOR INITIAL
a 3 400.
a ljil ANALYTICAL-EROSM a
W PRESSURIZATION RAT m 200' 3 --MPERIMENTAL DATA I 0
u CONDITIONS AND DATA n
ul W K
SEE TABLE I FOR INITIAL
0 I 0 0.1 a2 0.3 0.4 I
t- TIME.SECOND t-TIME,SECOND ~
FIGURE IO. CHAMBER PRESSURE TRANSIENTS FOR COMBINED CYLINDRICAL FIGURE It CHAMsER PRESSURE WSIENTS FOR COMBINED CYLINDRICAL PELLET IGNITER AND PYROGEN IGNITER OPERATION INAMOTOR PELLET IGNITER AND PYROGEN IGNITER OPERAVON m A MOTOR
I
i
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x x x x ANALYTICAL-EROSIVE BURNING AND --*ANALYTICAL
PRESSURIZATION RATE CORRECT -EXPERIMENTAL DATA
SEE TABLE I FOR INITIAL CONDITIONS AND DATA
W
3 v) v) W
a 800 -
i
IGNITER AND EROSIVE BURNING i i i
a e
m z a I 0
IGNITION SPIKE PRODUCED BY IGNITER
a 4 0 W
8 X x 0 - I I I I I 1
I
0 8 16 24 32 40 t-TIME ,SECOND
FIGURE 12. CHAMBER PRESSURE TRANSIENTS FOR COMBINED CYLINDRICAL P U T IGNITER a PYROGEN IGNITER OPERATION IN A SLOTTED TUBE MOTOR
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