02- Brl-mr-3663(Ignition Methods for a 155-Mm Regenerative Injection Liquid Propellant Gun_feb1988) 24p

7/30/2019 02- Brl-mr-3663(Ignition Methods for a 155-Mm Regenerative Injection Liquid Propellant Gun_feb1988) 24p

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MEMORANDUM REPORT BRL-MR-3663

1938 - Serving the Army for Fifty Years - 1988

CD1 0)

IGNITION METHODS FOR A 155-MM REGENERATIVEINJECTION LIQUID PROPELLANT GUN

JAMES DESPIRITO DTICJOHN D. KNAPTON . ELECTE" JUN 2 r, 1988

FEBRUARY 1988 -

APPROVED F0 R PUBLIC RELEASE; DISTRIBUTION UNLIMITED.

U.S. ARMY LABORATORY COMMANDBALLISTIC RESEARCH LABORATORY

ABes t AvaaRONeNCBest Available Copy


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UnclassifiedSECURITY CLASSIFICATION OF THIS PAGE

REPORT DOCUMENTATION PAGE 1 amlo-oaIa PR ECURI"TY CLASSIFICATION 1b. RESTRICTIVE MARKINGSunci fied

20. SECURITY CLASSIFICAT1ON AUTHORITY 3. ISTRIBUTION fAVAILARILITY OF REPORT2b. DICLASSIFICATIONIDOWNGRADING SCHEDULE4. PERFORMING ORGANIZA~IO REPORT NUMIER(S7, 5. MONITORING ORGANIZATION REPORT NUMBER(S)BRL-MR-3663

ItlWOOFflffMIf 19ANI ATION 5b. OFFIC SYMBOL' 76. NAME OF MONITORING ORGANIZATIONryarch LabSLCBR-IB-B

S OW, note an zipco*I 7b. ADORES$ (city,tate, #nM MI d)Aberdeen Proving Ground, MD 21005-5066

Be, NAME OF FUNDING/ PONSORING I b.OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBERIORGANIZATION (if applikablis)SC.BDDRSS (Cft. state, rWd ri p C"=i __0.__SOURCE ____OF__FUNDING_____________

ELEMENT NO. CII NO. rESSON NO.

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TABLE OF CONTENTS

I. INTRODUCTION 1II. RLPG IGNITER DESIGN REQUIREMENTS 2

III. IGNITER CONCEPTS 51. ELECTRICAL IGNITION 62. EXTERNAL IGNITER SYSTEMS 83. INTERNAL IGNITER SYSTEMS 84. NON-LIQUID PROPELLANT IGNITION SYSTEMS 9

IV. DISCUSSION AND CONCLUSIONS 11REFERENCES 13DISTRIBUTION LIST 15

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LIST OF FIGURES

1 30-,m RLPG Solid Propellant Igniter 22(a) 30-m. Solid Propellant Igniter Test,

Chamber Pressure 32(b) 30-mm Solid Propellant Igniter Test,

Igniter Booster Pressure 43 Electrical LP Igniter 7

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I. INTRODUCTIONArtillery system studies, based on the 155-mu self propelled

howitzer (SPH), have shown that there are potential logisticaladvantages of using a 1 liquid propellant gun in place of the conventionalsolid propellant gun. The logistical advantages of the use of liquidpropellant (LP) include increases in propellant inventory, both instorage areas and on the SPH, reductions in handling and transportationthroughout the supply chain, and an increase in projectile inventory onthe SPH. In addition, the use of an ignition system which uses theliquid propellant as an igniter charge would further increase th eadvantages of the Regenerative Liquid Propellant Gun (RLPG) system.

The ignition of liquid propellants was investigated during the workdone on bulk loaded liquid propellant guns (BLPGs). Most of theresearch focused on conventional pyrotechnic or electric spark systems,although some studies included ignition sources suPh as ho t wires,lasers, ultrasonic devices, and chemical ignition. Research waseventually directed towards the RLPG because of problems that persistedin relation to the control of ignition and combustion during theinterior ballistic cycle of bulk loaded guns.

The General Electric Company began investigating the regenerativegun concept in an IR&D program in the early 1970's. Many of the RLPGfixtures tested to date have relied on an external pyrotechnic igniter.In this type igniter, the solid propellant igniter charge is burned athigh pressure, external to the gun chamber, and the hot gases andburning particles are vented into the combustion chamber. An igniter ofthis type, used to ignite 30-mm RLPG fixtures, is shown in Figure 1.The solid propellant igniters used at General Electric have been ofsimple design and have consistently ignited the LP in a reproduciblemanner. However, there has no t been a detailed igniter research effortin the development of the RLPG fixtures during the past ten years. Norhas there been an effort to optimize the igniter design in use.Instead, the goal has been to develop a simple igniter with reliable andcontrollable output that leads to sustained ignition of the injectedliquid propellant.

The LPs currently being used in the United States are aqueoussolutions of nitrate malts, with hydroxylammonium nitrate (HAN) as theoxidizer component and an aliphatic amine as the fuel component. Therehave been several f rmulations of the HAN based propellants developed inthe past few years. The differences in the LP's are the type andpercentage of the fuel component and the percentage of water. One ofthe current formulations in Liquid Gun Propellant (LGP) 1845. The fuelis triethanol ammonium nitrate (TEAN). The composition of LGP 1845(based on weight) is 20.0% TEAN, 63.2% HAN, and 16.8% water. Based onthe requirements of the gun system, the HAN based liquid propellantscurrently hold the greatest promise fo r use in medium to large artillerygun.

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The objective of this report is to present the concepts that arebeing considered fo r an ignition system of a 155-rn RLPG.

NIA01 LECTRICIATOR HOUSING

IGNITER BODY

;R J2Ift9 TRANIDUCCR

V*NIJER VENTAS AGE

Figure 1. 3-mm RLPG Solid Prooellant Igniter

II. RLPG IGNITER DESIGN REQUIREMENTSIn this section the design requirements for the ignition system of"a155-mm RLPG are presented. The reader is referred to Reference 1 for"adiscussion of the RLPG concept.The design requirements are formulated from the igniter experience

the General Electric Company has obtained with their medium and largecaliber fixtures. The GE ignition systems consist of an electricallyinitiated primer followed by a solid propellant igniter charge.However, it is desirable that the ignition system for advanced weapondevelopment consist of a liquid propellant ignited by an tnergy sourcealready on the self propelled howitzer. This would offer significant

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logistical advantages by not introducing additional items into thesupply train. Regardless of the composition of the ignition system, amajor requirement on performance is that the ignition system ignite amain charge in a prompt, smooth manner and that it do so across atemperature range from -55 0 C to +65 0 C.

Two important performance characteristics of the ignition systemare peak pressure in the gun chamber and the rise time to that pressure.From parnt experimental tests, it has been found that the pressuregenerated in the combustion chamber from the igniter should be in therange of 17 to 21 Moa. The rise time to this pressure is a function ofcaliber. The rise time should be 1 to 3 ms in a 30-mr and 3 to 5 ms ina lrge caliber RLPG. In order to examine the performance of the 30-mmR1.FO solid propellant igniter, several tests were performed firing theigniter into a closed chamber. Pressures were measured inside theigniter chamber and the closed chamber. The results of a typical testare shown in Figures 2a and 2b. The volume of the igniter3 chamber isabout 7 cm and the volume of the closed chamber In 118 cm . Theinitial chamber volume of the 30-mn RLPG is 95 cm , therefore, the peakpressure of 13.1 MPa shown in Figure ?a is slightly lower than would beachieved in the gun fixture. The rise time of 4 as is close to what isachieved in the gun fixture. The pressure-time curve for the igniterchamber, Figure 2b, can vary depending on the type of igniter used.However, the 155-mm RLPG ignition system must produce a chamberpressure-time curve similar to that illustrated in Figure 2a. Theigniter output characteristics shown in Figures 2a and 2b have led toreproducible behavior.

30-MM SOLID PROPELLANT IGNITER TESTCHAMBER PRESSURE175

.- It.

ta-

TIME (MS)Figure 2(a). 30-mm Solid Propellant Igniter Test. Chamber Pressure

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30-MM SOLID PROPELLANT IGNITER TESTIGNITER BOOSTER PRESSURE13 1 "IN-

0..

w- a.'

1(

TIME (MS)

Figure 2(b). 30-mm Solid Pronellant Ignitmr Test.Imniter Booster Pressure

Other parameters important to the design of an ignition system arethe combustion chamber volume, the initial piston motion, the shot startpressure, and the initial propellant sheet thickness. The combustionchamber volume vill determine the amount of igniter charge that isrequired to attain the specified peak pressure and initial pressure riserate. The combustion chauer volume fo r the 155-mm RLPG is expected tobe on the order of 6500 cm . It has been calculated that a chamber ofthis size will require up to 250 to 300 grams of liquid propellant toproduce the required initial pressure. The initial piston motion couldcause a pressure drop in the combustion chamber if the initial chambervolume is too small or if the injected propellant is not immediately-ignited. A pressure drop would reduce the effectiveness of the igniter.*The projectile shot start pressure can have a similar effect if theprojectile starts to move an a result of the igniter pressure.Therefore, it is desirable that the projectile shot start pressure behigher than the pressure produced by the ignizer. The thickness of theliquid propellant sheet vhen it first enters the combustion chamber hasa large effect on the efficiency of the ignition system. If this sheetis too thick, the ho t gases from the igniter may be quenched from thelarge amount of propellant entering the combustion chamber and unburnedpropellant may accumulate in the chamber. The initial sheet thickness

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can be adjusted to the needs of the ignition process. However, thelower limit will have to be set by the low temperature operatingrequirements, due to the increasing viscosity of the LP at lowtemperatures.

III. IGNITER CONCEPTSThere are two basic igniter concepts being considered. Thesediffer in the location at which the propellant igniter charge is burned,

either internal to the gun chamber, or external to the gun chamber. Theinternal ignition system has the advantage that it will not add a greatdeal of size to the total gun system since the igniter charge will beburned at a lower pressure inside the gun chamber. The external igniterrequires an external prerombustion chamber which may increase the sizeof the total gun system. However, both the internal and the externalsystems can be designed to integrate efficiently with the gun system.

In an internal igniter, the liquid propellant igniter charge isburned inside the gun combustion chamber. The density of lolding forthe liquid propellant igniter charge will be about 0.04 g/cm in orderto develop the required pressure of 15 to 21 MPa, The advantage ofburning the igniter charge inside the combustion chamber is theelimination of a high pressure, external precombustion chamber appendedto the gun. However, it is not known at this time whether asufficiently high mass burning rate of the liquid propellant ignitercharge can be achieved at this low loading density.

The external igniter has the advantage that the propellant ignitercharge can be burned at a high loading density and thereby obtain a moreefficient burning of the liquid propellant. The ho t gases produced willthen be vented into the combustion chamber, possibly along with someburning propellant, where work can be done on the differential areapiston and the liquid propellant charge can be ignited. Anotheradvantage of the external igniter may be a greater control of igniterperformance, namely, maximum pressure and pressure rise rate. Adisadvantage of the external igniter, since the Igniter charge will burnat high pressure, is that the precombustion chamber must be somewhatbulky, adding to the overall size of the breech. Another disadvantageis that the high pressure gases will vent into the gun chamber through arelatively narrow passage, which may be susceptible to a high rate oferosion.

Regardless of the type of ignition system chosen, it is desirablethat the ignition energy source be one that is readily available on theself propelled howitzer. The logical choice is to use electrical energyas the initiating source fo r the igniter. Although there are possiblyother methods of ignition, such as laser, acoustic cavitation, orcompression ignition, electrical ignition will be given the mostattention due both to its promise as an ignition source and itslogistical advantage.

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1. ELECTRICAL IGNITIONWork was done on igniting liquid propellant charges using an

electric discharge in th e bulk loaded l iquid propellant gun. Work inthis area was done by Puleepower Systems Incorporated (PSI), the NavalWeapons Center (NWC), th e Naval Ordnance Station (NOS), and CalspanCorporation. The reader is referred to Reference 2 fo r a review of th etest results on this subject. From the results of this work it wasconcluded that an electric discharge in a conductive liquid propellantcan be broken down into two stages: (1) an ohmic or formative heatingwhich occurs prior to breakdown of the propellant, and (2) an arc orplasma phase operation that occurs after breakdown. The formation of anarc through the liquid is difficult to obtain in highly conductivefluids Jito the liquid propellants under consideration. More recentstudies indicate that an alternate mechanism fo r electrical ignitionof th e propellant may be electrolysis. The current flow is believed toinduce ion migration, which causes an increase in the nitrate ionconcentration near th e anode, This results in an increase in th enitronium ion concentration at the anode. It is known that th enitronium ion initiates reaction in the propellant and it is believedthat this reaction causes a vapor sheath to form around the anode.Then, depending on several factors, an arc may discharge between th eanode and th e vapor-liquid interface, not between the electrodes.

A type of electr ical igniter that may have a potential use aseither a bulk loaded or a regenerative igniter is the plasma plug.Research has been done in recent years on the application of pulsedplasma jets for improving ignition and burning ratis in the internalcombustion engine. This work was done by Weinberg who used hydrogengas in a modified automobile spark plug. In this modified plug, th ecenter electrode is enclosed in a small chamber with a vent hole. Thisdevice operates by discharging a current in the plug. The rapid heatingcaused by the discharge causes the medium inside the plug to dissociateinto fre 6radicals and eject from the plug at high velocity. Recentstudies have shown that these plasma plugs can be used to ignite HANbased liquid propellant* The amount of propellant used in the plug wason the order of 0.025 cm. The ignition characteristics of the plugsfell into two groups. One ignition type, which was usually obtained atth e higher capacitor charging voltages, is characterized by a plasma arcdischarge which probably formed in an air gap between the electrodesabove th e propellant. The second type were usually obtained when th echarging voltage was relatively low and th e plug was filled withpropellant or other highly conductive fluid. The first type of ignitionled to a plume of hot, reacting propellant venting from the plug. Thesecond type of ignition le d to the venting of unburned liquid propellantfrom the plug followed by burning LP and gases. In this second case th ereaction was believed to have started in the vicinity of the centerelectrode, which was the anode,

Before a plasma plug type igniter can be considered aj a componentof an ignition system for a 155-mm RLPG, the device must be scaled up insize to make sure the performance characteristics are not size

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dependent. This is one objective of the current research effort at theBRL. TIe igniter currently designed has a nominal propellant capacityof 2 cm . This igniter is shown in Figure 3 and represents an increasein propellant volume of eighty times over the q1ount tested inReferences 5 and 6. An igniter containing 2 cm of propellant is closeto the size needed fo r a 30-un RLPG. One goal of the study, therefore,is to test this type of igniter in the 30-mm RLPG at the BIRL. Theelectrical igniter shown in Figure 3 works in a similar fashion as theplasma plug. The maximum pressure obtained in the igniter will becontrolled by the area of the venting orifice. The igniter will bevented into a closed chamber and the output pressure will be recorded.The operation of the igniter will be studied at ch r~er pressures up to21 MPa, unlike the plasma plugs studied previously , which were testedat atmospheric pressure only. This design is best suited fo r a mediumcaliber RLPG Igniter or the first stage of an ignition train fo r alarger caliber weapon.

There are many parameters of the igniter that will be studied sothat optimum performance will be obtained. These parameters include:the polarity of the center electrode; the length of the centerelectrode; the length of the outer electrode; the size' of the ventingorifice; and the type of venting orifice. It has been observed that amore vigorous reaction occurs when the center electrode is positivelycharged. The length of the center and outer electrodes should affectthe location of the initial reaction. The size of the venting orificeaffects the mass flow rate out of the igniter and hence, the maximumpressure obtained within the igniter. It also affects the rise rate ofthe pressure in the chamber into which the igniter vents. The type ofventing orifice used, single or multi-holes, will affect the way inwhich the material is vented from the igniter and the size and shape ofthe venting plume.

CAVITY HOUSINGBASEINSULATORELECTRICAL INSULATION

IGNITER BODY

CENTER ELECTRODE ORIFICE INSERTFigure 3. Electrical LP Igniter

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2. EXTERNAL IGNITER SYSTEMSThe electrical igniter described above vould be an external igniter

since it would be located outside the combustion chamber, with the LPcavity serving as the pNecombustion chamber. With an LP igniter chargevolume of 150 to 200 cm fo r a 155-tm RLPG igniter, the ignition systemmay resemble an electrically ignited medium caliber bulk loaded LP gun.However, the reproducibility problems that were encountered in the BLPGfirings are expected to have less bearing on the ignition system sincethe generated gas vents into the larger combustion chamber wherecombustion anomalies would be filtered out. The loading density withinthe igniter precombustion chamber will be high, therefore there may beefficient propellant burning, especially fo r small charges. A bulkloaded, external ignition system of this type offers an ignition systemwhich is no t excessively complicated.

Another type of external igniter that could be employed in the 155-mm RLPG would be a regeneratively injected igniter charge. The igniterwould essentially be a regenerative liquid propellant gun mechanismabout the size of a medium caliber RLPC. A small liquid propellantinitiator would fire into the precombustion chamber, starting theregenerative pumping of the LP , which would then ignite. The processwould b, the same as in a medium caliber RLPG firing. However, insteadof doint ,ork on a projectile, the burning gases from the ignition inthe precombustion chamber would vent into the combustion chamber of the155-mm RLPG. It is very likely that a system such as this would worksince the principles of the regenerative system are well founded. Thissystem would offer effective control of the igniter output which couldbe achieved by varying both the mass injection rate and the LP ignitercharge volume, The primary disadvantages of this system are itsbulkiness and its complexity.3. INTERNAL IGNITER SYSTEMS

In an internal ignition system, the propellant igniter charge isburned inside the combustion chamber of the gun. Using liquidpropellant as the igniter charge, there are two configurations that canbe employed. Both of these igniter systems entail the burning of theigniger charge at a relatively low loading density of approximately 0.04g/cm . There are issues which must be addressed in order to evaluatethese internal systems. These are: (1) the repeatability of the igniteroutput; (2) the volume of LP which can be ignited in the required time,which is related to ; (3) the mass burning rate needed to support thecombustion at the low loading density.

The first system is a pool type igniter. In this system, theigniter charge is in the form of a pool in the combustion chamber. Asmaller electrical type igniter would be used to ignite the pool. Thisconcept is probably not feasible fo r the total igniter charge fo r largecaliber RLI~s

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Another internal igniter concept is a spray type igniter. In thissystem, the LP igniter charge would initially be located in a reservoir,external to the gun chamber. The LP can be injected into the gunuhamber by pressurizing a piston with external gas pressure. Anothermethod of injecting LP would be to force early regenerative pistonmotion in order to generate the spray. After the LP is injected intothe chamber in a highly atomized form, an initiator would be fired intothe combustion chamber in order to Ignite the charge. Some of the LP"igniter harge may accumulate in the chamber when it is injected,therefore not all the LP ma y be ir atomized form at ignition. Since thecharge will be mostly in the form of dtoplets, the mass burn rate may behigher than that obtained for the pool type of ignition system, due tothe increased propellant surface area.4. NON-LIQUID PROPELLANT IGNITION SYSTEMS

Ignition systems which use only the liquid propellant itself as theigniter charge are the most desirable because of the logisticaladvantages. However, two systems that would utilize an igniter chargeother than LP were studied. These systems are a hydrogen-air mixtureand a fuel-air mixture. These materiels could be used in eitherexternal or internal ignition systems.The concept of using a hydrogen and air 8mixture as an ignitercharge for the gun was suggested by A. Birk. This system would operateby pressurizing the combustion chamber of the RLPG with a hydrogen-airmixture. The mixture would then be ignited and would pressurize thecombustion chamber and start the RLPG process. A system fo r storinghydrogen, which was reported to be safe, is a metal hydride system. Inthis system the hydrogen is stored in a storage unit in solid stateusing metal hydridee Metal hydrides are formed when certain metalalloys are exposed to hydrogen gas. These alloys absorb large

quantities of hydrogen and form metal hydrogen compounds, where thehydrogen is distributed throughout the metal lattice. Metal hydridestorage is said to be safer than compressed gas or 9 liquid hydrogenstorage and have higher hydrogen storage capacity. The largesthydrogen storage unit described in Reference 9 has a stored volume of2,500 liters, a flow rat" of 0 to 85 liters per minute, and an outputpressure of 0.1 to 2.0 MPa.

A study was performed to determine the feasibility of using such ahydrogen storage system in a hydrogen-air ignition system. The volumeof hydrogen that in required for combustion with air to produce a finalpresnure between 17 And 21 MPa was determined using the NASA-LEWISthermodynamic code. The amount of hydrogen and air jequired as thendetermined fo r chamber volumes of 50, 500, and 5000 cm . The resultsfo r a final pressure of 20.4 MP& are summarized in Table 1.

For a combustion chamber volume of 5000 cm3 , 39 liters of hydrogenat STP are required to produce the desired chamber pressure. Based on astored volume of hydrogen of 2250 liters, each storage unit wouldcontain enough hydrogen fo r 57 firings before replacement or refilling.9

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In the same 57 firings, less than 500 liters of liquid propellant wouldbe required fo r the main charge. Therefore, a hydrogen-air ignitionsystem would occupy four times the volume of the main propellant charge.Another negative factor in this system is the fact that storing hydrogenon the vehicle may increase the vulnerability of the system.

TABLE 1. Required Hydrogen and Air at ST P to Give Final Pressureof 20.4 'Pa fo r Three Different Chambers.

Chamber Pressure Required Required *NumberVolume initial** final Hydrogen Air oftotal H2 Firingscm3 MPa MPa MPa liter wole liter mole

50 2.9 0.85 20.4 0.39 0.017 0.92 0.041 5769500 2.9 0.85 20.4 3.9 0.174 9.2 0.412 5765000 2.9 0.85 20.4 39. 1.74 92 . 4.12 57

* The number of firings listed in the last column is based on aneffective stored volume of 2250 liters of hydrogen.** Column 2 lists the initial total pressure.Column 3 lists the initial partial pressure for hydrogen.

The calculations also show that 92 liters of air at STP arerequired fo r each firing. A calculation was made to determine the powerrequired fo r operating an air compressor to deliver the required air,assuming 50% compressor efficiency. The calculation was based on anideal gas and the adiabatic power to generate a required air flow. Theair flow required was based on a firing rate of a proposed Advancedfield Artillery System 155-mm, which is four rounds in 15 secondsfollowed by a sustained rate of six rounds per minute. The powercalculations were made using the sustained rate of six rounds perminute. A 0.0283 m air storage tank is used in order to accommodatethe initial higher firing rates. It was calculated that a 15 to 20horsepower, multistage compressor would be required under theseconditions, which is no t unreasonable. It can then be concluded thatthe required air is not a limiting factor.

The hydrogen-air ignition system has an overall negative impact onthe logistics of the gun system because of the number of componentsneeded and the potential fo r increased vulnerability of hydrogenstorage. The fact that space is needed for hydrogen storage units and amultistage compressor, in addition to an electric ignition system, makesthis system burdensome.

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Another study was performed based on the use of the artilleryvehicle fuel and air as an ignition source. In this study, JP4 wa sselected for cNvenience in order to make use of data generated in anearlier study. The volume of JP4 required fo r combustion with air toproduce a final pressure of 20.6 (Pa was estimated based on the thermo-chemical calculations summarized in Reference 11. These show that amaximum piessure of 43.6 (Pa would be expected from a loading density of0.05 g/cm . Assuming an ideal gas, the loading density requiNed toobtain a pressure of 20.6 MPA was estimated to be 0.0238 g/oen. Theequivalence ratio fo r the combustion of JP4 and air, obtained fromReference 12 , is 14.78 mf/ua, where mf is the mass of the fuel and ma isthe mass of the air. For stoichiometric combustion, the required voTumeof air and the volume of JP4 were determined based on the equivalenceratio and the loading density required to yield the desired finalpressure of 20.6 NPa. The results are presented in Table 2.

TABLE 2. Initial and Final Conditions fo r StoichiometricCombustion of JP4 and Air for Cases Suitablefor a RLPG Igniter.Chamber Pressure Required RequiredVolume initial final JP4 Air

cm3 MPa KPa gram liter mole50 1.86 20.6 0.075 0.86 0.0384500 1.86 20.6 0.753 8.6 0.384

5000 1.86 20.6 7.533 86. 3.84".............................W............................u......

The calculations show that 86 liters of air at STP is required forcombustion with the fuel. This requirement should no t pose a problem ifanalyzed in the same fashion as in the hydrogen air system. However,the fact that this is a multicomponent system, like the hydrogen-airconcept, increases the logistical burdens.

IV. DISCUSSION AND CONCLUSIONSThe four concepts which use the liquid gun propellant as the

igniter charge show the greatest potential for use as a 155-rm RLPGignition system. The bulk loaded external igniter is the least complex,bu t would entail mounting a bulky precombustion chamber onto the breechof the gun system. The regeneratively injected external igniter hasgood potential for success, bu t would add complexity and size to thesystem. The pool type internal igniter is perhaps the least complexsystem, however it offers the least control of the ignition process.The spray type igniter, like the pool type igniter, introducesuncertainties about the combustion of the L? at low loading densities.

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The latter two concepts will have to be tested in order to evaluatetheir potential fo r implementation.

The hydrogen-air and the fuel-air systems are not being tested atthe BRL because of the additional components needed in comparison to anall LP ignition system. The hydrogen-aLr and fuel-air systems requirestorage of the hydrogen or fuel, a multistage air compressor, a fuelpump or injector, and an electric ignition system. An all LP systemwould require only the electric ignition system and possibly an injectorif the internal, spray igniter was being used. The filling of LP intothe igniter could be performed by the main LP charge fill system and,therefore, does not add to the complexity of system.

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REFERENCES1. Morrison, W.F., Knapton, J.D., Klingenberg, G., "LiquidPropellants For Gun Applications," BRL-TR-2632, U.S. ArmyBallistic Research Laboratory, Aberdeen Proving Ground, HD,January 1985.2. Klingenberg, G., Knapton, J.D., Morrison, W.F., "Review on LiquidGun Propellant Ignition Studies," Ernst-Mach-Institute, V 7/83,July 1983.3. Klein, N., "Liquid Propellants For Us e in Guns -A Review," BRL-

TR-264l, U.S. Army Ballistic Research Laboratory, Aberdeen ProvingGround, MD, February 1985.4. Mandzy, J,, Cushman, P.G., Magoon, I., "Liquid PropellantTechnology Final Report," BRL-CR-546, U.S. Army Ballistic ResearchLaboratory, Aberdeen Proving Ground, ND, October 1985. (ContractNo. DAAK-ll-78-C-0054)5. Klein, N., "Liquid Propellant Ignition Studies,"' Proceedings ofthe 20th JANNAF Combustion Meeting, CPIA Publication 383, Vol. 1,p 473, 1983.6. Klein, N., Weinberg, F.J., Carleton, F.B,, "Ignition Phenomena inEnergetic Liquids," ARBRL-TR-02514, U.S. Army Ballistic ResearchLaboratory, Aberdeen Proving Ground, MD, August 1983. (AD B077357L)7. Weinberg, F.J., "Plasma Jets in Combustion," IMechE ConferencePublication, C45/83, pp. 65-72, 1983.8. Birk, A., 1USA Ballistic Research Laboratory, private communicationto J.D. Knapton, January 1985.9. Ergenetics, 681 Lawlins Road, Wyckoff, New Jersey 07481.

10. Calculations courtesy of E. Freedman, USA Ballistic ResearchLaboratory, 24 January 1985.

11. Stansbury, L. Jr., Shearer, R.B., "Tables of Computed Thermo-dynamic Propertien of Selected Monopropellants," BRL-R-1579, U.S.Army Ballistic Research Laboratory, Aberdeen Proving Ground, ND,1972.1.2. Knapton, J.D,,, Stobie, I.C., "The Application of Fuel AirPropellant for Use in Weapons," BRL-R-1654, U.S. Army BallisticResearch Laboratory, Aberdeen Proving Ground, MD, February 1973.

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12 Commander 3 DirectorDefense Technical Info Center Banet Weapons LaboratoryATTN: DTIC-DDA Armament R&D CenterCameron Station US Army AMCCOHAlexandria, VA 22304-6145 ATTN: SMCAR-LCB-TLE. ConroyDirector A. GrahamDefense Advanced Research Watervliet, NY 12189

Proj BltdAencyATTN: H. Fair 1 Commander1400 Wilson Boulevard US Army Armament, MunitionsArlington, VA 22209 and Chemical CommandATTN: SMCAR-ESP-L

1 HQDA Rock Island, IL 61299-7300DAMA-ART-MWashington, DC 20310 1 CommanderUS Army Aviation ResearchCommander and Development CommandUS Army Materiel Command ATTN: AMSAV-EATTN: AMCDRA-ST 4300 Goodfellow Blvd5001 Eisenhower Avenue St. Louis, MO 63120Alexandria, VA 22333-0001 1 Commander13 Commander Materials Technology LabArmament R&D Center US Army Laboratory Cm dUS Army AMCCOM ATTN: SLCMT-MCM-SBATTN: SMCAR-TSS M. Levy

SMCAR-TDC Watertown, MA 02172-0001SMCAR-SCA, B. BrodmanR. Yalamanchili 1 DirectorSMCAR-AEE-B, D. Downs US Army Air Mobility RschA. Beardell and Development LabSMCAR-LCE, N. Slagg Ames Research CenterSMCAR-AEE-B, W. Quine Moffett Field, CA 94035A. Bracuti

J. Lannon 1 CommanderSMCAR-CCH, R. Price US Army CommunicationsSMCAR-FSS-A, L. Frauen Electronics CommandSMCAR-FSA-S, H. Liberman ATTN: AMSEL-EDPicatinny Arsenal, NJ Fort Monmouth, NJ 0770307806-5000

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DISTRIBUTION LISTNo. of No. ofCoie Oganization Co2aeu Organiz~tIM

Commander 1 DirectorERADCOM Technical Library US Army TRADOC SystemsATTN: STET-L Analysis ActivityFt. Monmouth, NJ 07703-5301 ATTN: ATAA-SLWhite Sands Missile RangeCommander NM 88002US Army Harry Diamond LabsATTN: SLCHD-TA-L 1 Commandant2800 Powder Mill Rd US Army Infantry SchoolAdelphi, MD 20783 ATTN: ATSH-CD-CSO-ORFort Benning, GA 31905CommanderUS Army Missile Command 1 CommaderRoch, Dev, & Engr Ctr Armament Rich & Dev CtrATTN: AMSKI-RD US Army Armament, MunitionsRedstone Arsenal, AL 35898 and Chemical Command

ATTN: SMCAR-CCS-C, T HungCommander Picatinny Arsenal, NJUS Army Missile & Space 07806-5000Intelligence CenterATTN: AIAMS-YDL 1 CommandantRedstone Arsenal, US Army Field Artillery SchoolAL 35898-5500 ATTN: ATSF-CMWFt Sill, OK 73503CommanderUS Army Belvoir R&D Ctr 1 CommandantATTN: STRBE-WC US Army Armor CenterTech Library (Vault) B-315 ATTN: ATSB-CD-MLDFort Belvoir, VA 22060-5606 Ft Knox, KY 40121Commander 1 CommanderUS Army Tank Automotive Cm d US Army Development andATTN: AMSTA-TSL Employment AgencyWarren, MI 48397-5000 ATTN: MODE-TED-SAB

Fort Lewis, WA 98433CommanderUS Army Research Office 1 CommanderATTN: Tech Library Naval Surface Weapons CenterPO Box 12211 ATTN: D.A. Wilson, Code G31Research Triangle Park, NC Dahlgren, VA 22448-500027709-2211

1 CommanderNaval Surface Weapons CenterATTN: Code 033, J. EastDahlgren, VA 22448-5000

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DISTRIBUTION LISTNo. of No. ofi Organization CopLe Or ization2 Commander 1 Director

US Naval Surface Weapons Ctr Jet Propulsion LabATTN: 0. Dengel ATTN: Tech LibraryK. Thorsted 4800 Oak Grove Drive

Silver Spring, MD 20902-5000 Pasadena, CA 911091 Commander 2 DirectorNaval Weapons Center National Aeronautics andChina Lake, CA 93555-6001 Space Administration

ATTN: MS-603, Tech Lib1 Commander MS-86, Dr. PovinelliNaval Ordnance Station 21000 Brookpark RoadATTN: C. Dale Lewis Research CenterCode 5251 Cleveland, OH 44135Indian Head, MD 20640 1 Director

1 Superintendent National Aeronautics andNaval Postgraduate School Space AdministrationDept of Mechanical Engr Manned Spacecraft CenterATTN: Code 1424, Library Houston, TX 77058Monterey, CA 93943

10 Central Intelligence Agency1 AF1L/SUL Office of Central ReferenceKirtland AFB, NM 87117 Dissemination BranchRoom GE-47 HQS1 Air Force Armament Lab Washington, DC 20502ATTN: AFATL/DLODL

Eglin AFB, FL 32542-5000 1 Central Intelligence AgencyATTN: Joseph E. Backofen1 AFOSR/NA (L.Caveny) HQ Room 5F22Bldg 410 Washington, DC 20505Boiling AFI, DC 20332 C3 Bell Aerospace Textron1 Commandant ATTN: F. BooradyUSAFAS F. PicirilloATTN: ATSF-TSM-CN A.J. FrionaFt Sill, OK 73503-5600 PO Box One

Buffalo, NY 142401 US Bureau of MinesATTN: R.A. Watson 1 Calspan Corporation4800 Forbes Street ATTN: Tech LibraryPittsburgh, PA 15213 PO Box 400

Buffalo, NY 14225

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7 General Electric Ord Sys Div 1 Science Applications, Inc.ATTN: J. Kandzy, OP43-220 ATTN: R. EdelmanR.E. Mayer 23146 Cumorah CrestH. West Woodland Hills, CA 91364K. BulmanR. Pate 1 Sundstrand Aviation OperationsI. Magoon ATTN: Mr. Oven BrilesJ. Scudiere PO Box 7202100 Plastics Avenue Rockford, IL 61125

Pittsfield, MA 01201-3698 1 Veritay Technology, Inc.1 General Electric Company ATTN: E.B. FisherArmament Systems Department 4845 Millersport HighwayATTN: D. Maher PO Box 305

Burlington, VT 05401 East Amherst, NY 14051-03051 IITRI 1 Director,ATTN: Library Applied Physics Laboratory10 W. 35th St The Johns Hopkins Univ.Chicago, IL 60616 Johns Hopkins Road

Laurel, MD 20707Olin Chemicals ResearchATTN: David Gavin 2 DirectorPO Box 586 CPIAChesire, CT 06410-0586 The Johns Hopkins Univ.ATTN: T. Christian2 Olin Corporation Tech LibraryATTN: Victor A. Corso Johns Hopkins Road

Dr. Ronald L. Dotson Laurel, MD 20707PO Box 30-9644New Haven, CT 06536 1 U. of Illinois at ChicagoATTN: Professor Sohail MuradPaul Gough Associates Dept of Chemical EngrATTN: Paul Cough Box 4348

PO Box 1614 Chicago, IL 60680Portsmouth, NH 038011 U. of MD at College Park

Safety Consulting Engr ATTN: Proftssor Franz KaslerATTN: Mr. C. James Dahn Department of Chemistry5240 Pearl St College Park, MD 20742Rosemont, IL 60018

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U. of Missouri at Columbia 3 University of DelawareATTN: Professor R. Thompson Department of ChemistryDepartment of Chemistry ATTN: Mr. James CroninColumbia, MO 65211 Professor Thomas BrillMr . Peter Spohn

1 U. of Michigan Newark, DE 19711ATTN: Prof. Gerard M. FasthDept of Aerospace Engr Aberdeen Proving GroundAnn Arbor, MI 48109-3796 Dir, USANSAAU. of Missouri at Columbia ATTN: AHXSY-DATTN: Professor F.K. Ross A)XSY-MP, H. CoheorResearch ReactorColumbia, MO 65211 Cdr, USATECOMATTN: AMSTE-TO-F

1 U. of Missouri at Kansas CityDepartment of Physics Cdr, CRDEC, AMCCOMATTN: Prof. R.D. Murphy ATTk: SMCCR-RSP-A1110 East 48th Street SMCCR-HUKansas City, MO 64110-2499 SMCCR-SPS-ILPennsylvania State UniversityDept of Mechanical EngrATTN: Prof. K. KuoUniversity Park, PA 16802

2 Princeton Combustion RachLaboratories, Inc.

ATTN: N.A. MessinaM. Summerfield475 US Highway One NorthMonmouth Junction, NJ 08852University of Arkansas

Dept of Chemical EngrATTN: J. Havens227 Engineering BuildingFayetteville, AR 72701

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Documents

02- Brl-mr-3663(Ignition Methods for a 155-Mm Regenerative Injection Liquid Propellant Gun_feb1988) 24p