Hydrogen IC engines

8/13/2019 Hydrogen IC engines

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NRELP-425-646 UC Category: 5 DE94006950

Hydrogen-AirReciprocating En

L. d l

g Evaluation ines

Southwest esearch nstituteSan tonio, exas

cncl ono: olucc

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Nationa Renewabe Energy Laboratory1617 Cole BoulevdGolen, Colorado 0401-9 nationl laboratory of the U.S. Depmet of EnergyOperate by Midwest Reserch Institute forthe US. Deprtment of EergyUnder Contract No DEC02-CH1009

Prepre uder Subcontract No W212266-1

June 1994


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NOTCENOTICE: This repo was prepared an account of work sponsored by an agen of the United States govement Neither he United States govenor any agency thereof, nor any of their employees, makes any waan, express or implied, or assumes any legal liability or responsibili for the acompleteness or usefulness of any informaon, appratus, product, or process discosed, or represents that its use would not infrnge prately ownedReferen herein to any specific mmercial product, pross, or sei by tade name, tdemark manufacturer, or otheise does not nececonstitute or imply its endorsement, remmendaion, or favoing by the United States goement or any agency ereof. The views and opinions of epressed herein do not nessaily state or reflect those of the United States goement or any agen thereof

Pnted in the United States of AmericaAailable from

National Technil nfomation SeiceU.S Depament of Commer

5285 Po Royal RoadSpringfied, VA 22161

Pce Microfche A01Pnted Copy A03

odes are used for pricing all publicaons. The cde is detemined by the number of pges in the pubication. nfomation peaining to the pcingcan be found in the current issue of the following publions which are generally aable in most ibraries Energy Research Abstracts (ERA); GoveReports Announceents and Index (GRA and I) Scientfc and Techncal Abstrct Repor (STAR) and publication NTS-PR-360 aailable from NTboe adress

Pnte on recyced pper


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Executive Summary

A esseti p of is eort ws or SwRI persoel o become failir wi e pogress made ihydroge el use i itel combuso ees rough resech coducte at e Musashi Istte ofechology (Musshi I over e past 20 or more yes Visits by SwRI persoel t Musashi Ii

oko d vice versa accomplished he go of shig experiece with hydroge els.

Te geer shape of he hydroge-ir (actly hydrogeioge mixig s measured by Rayleigh lightscaterig measureme ws prediced by he model iudig boh il ad rdi viaosHowever e predicted hydroge coceas were greater a e msred values ad e wid ofthe computed hydrge-ioge plume based o schliere photogrhy was greater e widmeasured by Rayleigh light scaerig ese observaios suggest some shorcomigs wih e modelsabili to edict experimet results s well as cosistecies i e expemeal results Teexrimetal measureme of hydroge coceatio suggest a sigicy rower jet wid th at

ifeed om schliere photographs rsiet eects of hydroge je propgatio rough he 17-disace betwee e ijector ve d ijector p e ot hdled propely i e X model whichwas developed for a diesel-ty ijeor where e vlve is very ose to e ijecor p

A umber of suggestios have ee veloped durig this stdy to aess e exeme sesitity of hesprkigiio evet i hydroge-eled egies Perhaps some of hese suggestios may be implemeted

i tre egie tests

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Contents

Background ..... ... . .. .. ... .. . ... ... . ........ ......... ... .. .... .. ....... . 1

Objecve ...... .. ... . .. ..... .. .. ... .. ....... ....... .... .... ... ... . ...... 2

Approach 2

Experimentl Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

etMixing Model . ... . .. . ... . .. . ...... .. ..... ...... .. .... .. .... . .. ..... ...

Comprison of Cculions and Meuremen for Hydrogen-Air Mixing ..................10

Discussion .... . .. . ... . ... . .. .... .... ....... ........ .... .. ..... . .... ... ..1

Summry nd Conlusions ...................................................1 8

Recommendions or Future Work .............................................1

References . .. .. ... . .. ..... ... .. .. .. ....... ....... ....... ...... ..........20

Appendix A Equations for Conservon of et Momentum Rated Fuel Mass Flux Free et nd Wall et .................................. A1

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List of Figures

F gure ypical ols of lr concnaon xprssd in trms of

quvnc ro for gasous l injd rough a simpl holp injctor,whr an quivnc rao of prsn a chmicly coct, orstoichiomc ixtr 3

2(a) Saightp hydrogninjction nozzl usd in Musshi Itsts . . 5

2(b) Expddtip hydrogninjction nozzl usd in Musashi Itsts 5

3 Highprssur bomb usd for hydrogn injctor tsts at Musshi I 6

4 Optic stup usd for hydrogn concnation masurmnts at Musashi I 6

5 Examls of signs om hydrogn concnation masurmnts at Musshi I 8

6 Compison of prictd (by J) nd msurd hydogn lconcnations in a hydrognniogn jt for saight injctor tip5 downs of injctor tip Pij = 24 A, Pchem 08 a

7 Compson of prictd (by EIX) nd msurd hydrogn lconcnions in a hydrognniogn jt for sght injctor tip 0 mmdownsam of injctor tip, Pij. = 24 a, P chem. = 8 a

8 Compson of prcd (by EIX) d masurd hydrogn lconcnons in a hydrognniogn jt for sght injctor tip 5 mm

downsam of th injtor tip, Pij. 24 a, P ch. 08 a 2 ompson o prcd (by EIX) nd masurd hydrogn l

concnations in a hydrogniogn jt fo saight injctor tip 20 downsam of injctor tip, Pij. = 24 a, P chem. = 08 a 2

0 Compson of prdictd (by E) nd msurd hydrogn lconcnations in a hydrogniogn jt for saight injctor tip 5

2

3

downsam of injctor tip, Pij 24 a, P chem. = 08 a 3

Compson of prdictd (by EIX) nd masurd hydrogn lconcnations in a hydrogniogn jt for sght injctor tip 0 mm

downsam of injctor tip, Pij. = 24 a, P chem. = 08 a 3Compson of prctd (by EX) d masurd hydogn lconcnations in a hydrogniogn jt for saight injctor tip 5 mdownsam of th injctor tip, Pij = 24 a, Pchem. = 08 a 4

Compson of prictd (by EIX) and msurd hdrogn lconcnations in a hydrognniogn jt for saight injctor tip 2 mmdowns of injctor tip, P 24 a, P chem. = 08 a 4

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List f igures(Cuded)

14 Cmpris f predcd d meured hydrge-nge jet m sight-pijectr, Pij. 186 A Pcm 108 a 15

15 Cmpris f predicd d meaed hydrgenge jet m sight-pijectr Pi. 245 A Pcm. = 108 a . . . . . 15

16 Cmpris f predcd d measured hydrge-nge jet m saightpijectr, Pi. 3 A Pcm. = 108 a 16

17 Cmpars f predicted d meed hydrgenige jet m saightpijectr, Pij. = 382 A Pcm. = 108 a . . . 16

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ydrogen-A r M x ng Evalua on n Rec proca ng Eng nes

Background

Hydrogeeled egies e atacve power sorces that do ot prodce greehose gses (C, wi

he eceptio of bed oil ad crbo mooide (CO) Te ehast prodc e ioge (N watervar (H, d iic oide (NO) Of these, oy ic oide is cosidered a problem Hydroge cbe bred i itealcombstio egies i vios ways Becase it hs a high atoigitio temperatre,it is more atactive s a el for spigitio egies th for compressioigitio egies

Te hydroge elir formatio for a spigited egie c be mied ete to the cylider or i thecylider Miig icylider c be either ely ijectio, which forms a homogeeos chge, or late

ijectio (e topdedceter, C so that e el bs s it is ijected, as i a diesel egieEteral miig of hydroge d ir is limited bo by the power at c be prodced d by bacigrogh the itae system Te power limitatio is de to ir beig displaced by hydroge gs Becasehe ir/el rao for a stoichiomeic mitre of hydroge is 24 by volme, e mimm ir ow ito

the egie is redced by abot 29% relave to ijeco of the el ito the cylider, redcig the

mimm egie power by a similr mo Bacrig ssociated wi eteal iig of e eloccrs whe preigitio of e el advces at every cyle l it ly occrs before e ite vveis closed, casig the me to propagate ito e premied chrge i the ite system d eplode(Fhma 1992) Oe approach to avoidig bacre is to mae e hydrogeair mitre e to slow

the me speed; s resls i a prtic limit of abot 50% of the power avilable om stoichiomeiccombstio of hydroge i the smesize egie (Fhma 1992) Ete miig ca reslt i veryhigh ececies der lea operao, bt is liited i mimm power

Tere re two choices for icylider ijectio of hydroge () erlycycle, lowpressre ijectioforig a emied chge, or (2) latecyce, highpressre ijectio (er C Te erlycye

ijectio is limited by preigio om hot srfaces d by ocg de to the very high me speedof hyoge (320 c/s for ich mitres verss 45 cm/s for most hydrocbo els; Glassma 1987)

Tis reslts i erac combstio d limits the power available Te preigitio prblem may besomewhat redced by ijectig cooled hydroge gs, bt is approach aps to be more eective for2soe egies for 4soe ees hama 1992)

Latecycle ijectio of hydroge overcomes the preigitio problem if e el ca be igited ely ithe ijectio process d the bed s it is ijecd However, the igito d brig c be veryrogh if the igitio tiig does ot low combso to occr vey erly i e ijectio process(Frhma 1992; Koyaagi et l 1993) Very cel cool of timig d locatio c helpcool e errac combstio lso, latecyle ijectio reqres high ijecio pressres to overcomee high cyider pressres, wi ijectio pressres of ot 1 a (Koyi et 1993) Tis latecye, highpressre hydroge ijecio may be more easily coolled ad more practical sig liqid

hydroge rather gseos hydroge Mshi Istte of echology (Msashi I), oyo, ap,has developed liqdhydroge storage d ighpressre liqid pmps d ijectio systems sitable foratomobiles d has sed em o sever demoso vehicles rha d omisawa 199)Storig liqid hydroge o veiles redces the weight reqiremets (Fhma 1991) However, it isa very lowtemperatre cryogeic el, d at, of corse, iodces a mber of hdlig ad storge

problems

I additio to the reqiremet for developig cryogeic el pmpig d hadlig systems, latecycle,directijectio of hydroge has bee limited by the eeme sesivity to sp tig d locatio(Fhma 1992; Koyagi e t l 1993) Hydroge has severl properies hat mst be cosidered ievatig is problem Frst, it h very wide amability limits, maig it esier to locate the spr

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in a combustible porion of the el-r plume, n sset when comped with gsoline However, becausee el is gseous raer n liquid when t is nected, ere is no liuid evaporaon to limit e buringrate Furher, for stoicomec mixtres, the laminr me speed of hdrogen is about four times atof gsoline Tus, f a sigcnt mount of hydrogen hs been sprayed into the cylinder before igion,the iitil combuson rate is so great tat mximum cylnder pressres e exceeded Terefore, e sprkmust occur erly in e injection process, before much hydrogen hs been injected s mes that esprk plug must be located close to the el njector, d e mixtre must be ignited before very much

el-ir mixing occued Figure 1 shows a contour plot of gaseous el-r mixing raos, expressedinterms of stoichiomey, where 10 is the "chemclly coect mixtre Note , ose to e injector,e graents in elair ratio re very high, mng it very cult to select a spkplug locon at isat a xtre ratio where gition is esily achievable, espelly consdering e fact at engine srl willdeect e el plume nd t chging engine seds will cause dierent ounts of deection Tiswas e problem addressed n is project: to evuate hydrogn-ar mixing in a directnjecon engine,erly n e injeon process

Objective

Te objective of is work ws to evlue hydrogen elr mixing in a direct-injection system for askited, hydrogeneled veicle, espely ely in the injection process Te purse of s work

was gain sucient understandng of e problem of errc combustion of hydrogen to deterne whatapproces might be ed to more esily ignite e hydrogenr plume in e enne Te computational

porion of is work ws performed at SwR, San Antonio, exs, wile e experimentl poron wasconducted at ussh in okyo Tis NEOE conact sponsored e work condued at SwRoly

Approach

Experimentl measurements of hydrogen-ir (acally niogen in place of r) mxing in a hydrogenel,directinjecon system were conducted at ussi Tese experiments ncluded mesurements ofhydrogen el concenaon by Rayleigh ght scaring of hydrogen d niogen (e background gsin e bomb), and by highspeed sclieren photohs of peneaon rates of hydrogen gs into aniogen-lled bomb Te Rayleigh light-scarng mesurements gave a deterination of relavemolecul concenation of hydrogen d nogen Te molecul concenation atios e e same asthe ratios by volume of the two gses, so ese raos cn be comped recy w ros computed bythe model e peneation res lso may be comped with peneaon estimates mde by e model

Te experiment mesuremen of hydrgen-r mixing om Musshi tess were comped wicomputatiol esmaes of ixing using e J computer model, a model prevously develped atSwR for esel el stdies. Speciig e cone gle of e elir jet om experimentalmeasrements, and the fel pressure nd hoe size of e injector hole, e elr mixing of a sadystegas jet cn be predicted in a twomensionl plne Te o dimensions re e il distce om the

njector tip nd the rdi stnce om e cenerlne of the je e nsient peneation re can be

esmated as a action of e steadystate neion of a pcel of el on e centerlne of the steadystate je


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w

20.

16EE 12

w 8u

4z 0t

-4_ -8


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Experimental Measurements

All experiment measurements were conducd at Mussi I by K Koyanagi, under te direction of Ymne nd S Furma nd colleagues Tese exriments were not nded by NL A completedescripon of te experimentl aatus nd results is beyond e sco of is project Howeve, some

background informaon as been provided by

Koyanagi nd is inluded ere wo yrogen injector

tips were cacterized for drogen concenaon downsem of e tips Te stndd or sigt pis sown in Figre (a), nd e expanded p is sown in Figure b) In bo cses, e valve is located1 upsem of e injector tip. Te injector p being tested ws monted in n elevated-pressre,

room-temperature bomb s sown in Figre 3 Te opc aatus for mng te Rayleig scattengmearements of drogen concenation is sown in Figure 4 Higspeed sclieren potoapy was

used for peneaon-rate mesreents on te stndd injector tip

Te ydrogen concenation measurements were based on Rayleig scateng measuremen, wicmeasure molecul scatering Hydrogen w injected into a niogenlled bomb As e ydrogendisplaced some of te niogen, te scatteng intensity was reduced since e smler ydrogen moleculeas a smler Rayleig scatering crosssection n e niogen molecule Te gener expression for

te scateng innsity isI = CN (1)

were I is e scateng intensiy in mks units of watsm; C is a constnt for e optic syste,

essenly eecve pat lengt, wt dimensions m; is e lser ligt intensity indnt on teolecule wit units of wats

; N is concenation of molecules in molecuesm; nd is te

Rayleig scateg cross-section in mmolecule

Tus, for te rst expement wen e bomb is lled wi just static niogen, e scatng intensity forniogen, I, is

()

were Na is e molecul concenon for te expement, wic is e moleculr concenation ofniogen, and is e Rayleig scateng crosssection for ogen

For e second experiment, wen yrogen is injected into e ogen-lled bomb, e scatengintensity is due to scteng o bo niogen and ydrogen Assung e mole action of niogenis f and te mole action of ydrogen is f, e combined scatng intensity for niogen plus ydrogen,I+' is

(3)

were fis e mole or oleculr) action of niogen molecules in e scatering volume, fis te olefraction of yogen molecules in e scateng volume, Nis e tot molecul concenation, nd

is e Rayleig sc eng cross-secon for ydrogen Because f + f 1 oy niogen nd ydrogene present in e bomb, e combined scaterin intensity may be wten as

(4)

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I '>- -- -

Fgure 2(a) Straghttp hydrogen-njeton noze ued n Muah T tet

7

' J > --\ f

- 1.5

Fgure 2(b) pandedtp hydrogen-njeton noze ued n Muah I.T tet


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igure 3 Highpressure bomb used for hydrogen injector tests at Musashi IT

3

1

1 1r-Ion ase

2 Lens

3 Cobuston

Chmber

4 Lens

65 Lens

6 Monocomao

7 P.MT

7

Figure4 Optial se-up used for hydroen conenration measurements a Musashi I.T

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Tis equaon may e solved for the mole acon of hydrogen as folows

(5)

If e injecon of hydrogen does not sigcnty inese the overl pressure and erefore e moleculrdensity in e om, d likewise if the high-velocity jet is ssumed to have e same pressue as estagnt gas in e om, ignong the no reducon in stac pressure nd densi wi velocity, nd

if e locl pressure increase at e head of e neng jet is ignored, en N N, nd

(6)

Because hydrogen is a smler molecule an niogen, its scatering oss-secton is smaller, nd thescatring intensity of e mixte is less n e scateng intensity of niogen aone. Some explesof the Rayleigh sceing intensity measurements 5 mm downseam of e injector p e shown inFigure 5 Note at scatring intenty actuly deeses wi ineing hydrogen concenation

Jet-Mixing Mode

SwRI developed a computer model cled J for evuatng el-ir mxing direct-injected, deseleled, compressionigntion engines prior to this NREOE project. Te J model simplies themixing process y ignorng e phase chge of diesel el om a liquid to a gas, eing e liquid asa dense gas. Tis is propriate since e limit to el-air mixing is usuly not due to evaporation of the

liquid el, ut to the mixing of the evporated el with the ir e cher (Heywood 1 88).However, s asumption of ignoring e liquidel evaporation is not issue the injection of gseoushydrogen (Te Musshi I design stores nd pumps the hydrogen as a yogenic liquid, en vaporizes

it nd injects it as a gas)

Te J model is descried in detail in Appenix A s it ws developed for diesel injecon someof the modicaons required to apply it to hydrogen gas injecton e desied elow. Tree ssumptionscommoy used in e alysis of jets were used to derive e equions used in is model:

(1) Te el mass-ow rate of e jet at every i coss-section is the se, and is equ to eel massow ra at the source.

(2) Te momenm rate of e jet at every cross-section is e se, and is equal to emomenm re of e jet at the source

(3) Te spreading angle of e jet is assumed to e constnt, nd e proles of veloci nd elmss acon re assumed to e selfsimilr nd to follow e poles desied inAppendix A.

Appendix A shows how, sg wi ese assumpons, e el-ir mixing rate of el nd ir repredicted. However, the appendix illusates the development of e model for an (apoximately)incompressile uid, iesel el Certain mocions were required to adt e model hydrogenTe chges required for hydrogenr mixing cculations re ouined in is section.

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0

Hydrg Jprssur = PiSingl e hole

zz

Measremt (Spark ga)

cr.I

) .Ql o. cc 0N-

Injection val lift

( \)I Pi:4_ Ma _. ressureI max=3.52Ma

100

0

. _ max=265MPa100

0 r I .=20Ma

max=172Ma100

0

2 3

Tim after al on (ms)

Figure 5 Examples of signals from hydrogen concentration measurements at Musasi I.T


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Te oginal equations for el masslow rate d velocit, shown in Appendix A, have been replacedwith equaons apprope for compressible gses Te equations used e based on mach number

relaionships om Shiro (1953); see especily Equaon 414b, pg 83; Equaon 416, pg 84; andEquaton 45b, pg 79 addition to el mass acons at were aready cculed, JX wsmoed to compu el volume actions a cn be comped direcy wi e Rayleigh light-scatengmeements of hydrogenniogen ros

Te mach number M rough e injection nozzle is calculated s

(7)

where p is e pressue upse of e injector, p is e pressue in e bomb, and ' is e specic heatratio Te mach number is convered into a veloci using e sonic velocity, c, wch is

c = V' (8)where R is e uvers gs constant, is e absolute temperate, d M is the molecular weightTe gs velocit in the nozzle is estmated om e mach number d e soic velocity as

(9)

where c is e dschge coecien Te el masslow rate in e injector is calculad as

(10)

where is e el mssow rate and A is the orice ea

Te JX model ws conscd for most incompressible el, while hydrogen is a compressiblegas Terefore, essenaly instaneous esion of hydrogen at e exit of the injector must be taken

into account Furer, e velociy prole in e injector is assumed to be plug ow wi uniform velociaoss e orice, while at e oce exit e jet must ansion into proximaly Gaussin prole

o address e problem of hydrogen gas expasion, raer n modeling e expsion of the hydrogengas at e exit om e injector, e gs is assumed to have aread expnded in e injector Te densiof e hydrogen in e injector is ereby reduced om its ctual densi by e rao bob Ip, wherebob is e background pressure in the bomb nd p is e pressue upse of e injector is

imporant to maintin e proper mass-ow rate and momentum rate (momentm * velocity) in einjector, so reducing e gas densi requires at the ea be increased by I bob Te el mass-owrate d e totl momentm re of e jet are constant at ever jet cross-secton downseam of einjector and e equ to at in e injector erefore, both must be correcy sced in e injector

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-u. 1 3 PRIT Q R

a 8>

z0

6

c:ztuz 40u

z0 2

d

j

ASSMD CO AG: deg.

p

0

,,,,,,, ,,,, r, , , ,,,,, ,,,, - - -2 2 6

H DSTANE FROM CENTERLINE O ET (mm)

Fure 6. Comparon o predted (y JETMIX) and meaured hydroen uel onentration in ahydronnten jet or tht njetor tp mm downtream o the njetor tp.Pinj. 294 MPA, Pchem 098 MPa

1a 8>

z0; 6 J0u

z.(

0 200>:

o MEASURED PRECTED

II

d

/10

ASSUME CONE ANG: 34 d9

\p

I

'

,\0 Star;1npill'jliio ' l ' ""' "'

o6 0-8.0-6.0 -40-2.00020

H10 DISTACE FROM CNTERUN Of JT (mm)

Figure 11 Comparison of predicted (by JETMIX and measured hydroge fuel concentrations in ahydrogen-nitrogen jet for straight injector tp 10 mm downstream of the injector tip,Pnj = 294 MPa, Pche. = 098 MPa

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z

6zLuz 4uz g 2

MEASUE- PEDCTE

0 b

ASSUMED CNE ANGL: 34 g

f 0 ; .=m

-8.0 -6.0 40 2.0 00 20 4.0 60 0DISTANCE FROM CENTERLNE OF JET (mm)

Figure 12 Comparison of predicted (by ETMI an measured ydrogen fue concentrations in aydrogennitrogen jet for straigt injector ip 1 mm downstream of te injector tip,P 294 MPa, Pchem 098 MPa

0>

ooooo ESUE ASSUMED CONE ANGL 334 - PREDCD

6

7o; 0 0 0

2

\ 00

-80-60 -40 20 0.0 20 40 60 0

DISTAE FROM CENTERLNE O JET (mm)

Figure 13 Comparison of predicted (by JETMI and measured ydrogen fue concentrations in aydrogennitrogen jet for straigt injector tip 0 mm downstream of e injector tip ,P 294 MPa, Pchem 098 MPa

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800 cco MESURED PENETATON RATE PREDICT. CONE ANGLE 22 eg Cd 0600 EXEMEAL DAA SHFD BY -.3 ms

-

EE so

Lu

5000 400z0

130.0 L 200

0c000

000 00 0

'

:

:, ' ' 1 ' ' ' ' J

-o5 o5 0 5 2 25 JoTIME FROM START NJECTION ()Figure14. Comparisonof predicted and measured hydrogen-ntrogenjetfromstight-tipinjector,

Pinj. = 1.86 MPA, Pchem. = 1.08 MPa.

80 f ooo MEASURED ENERAON RATE EDCED. CONE ANGE 22 eg Cd 05EPERMEAL DAA STED 3

700-

E .sooLu 50I(0 4z0 3c:1L 2a

. ao0

0ccc0

cc0 00

ao5o w oWo o. s2 o2s3.o IME ROM SRT OF INECION

Fgure 15. Comparison of predcted and measured hydrogen-nitrogen jet from straght-tip injector,Pnj = 24 MPA, Pchem. = 1.08 MPa.

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conoing th ow is just upsam of injctor hos, as is c in is injctors Howvr,for s xprimnts, cono vv was foowd by a 17-mm-ong, -mmitr injcon tub,as shown in Figur 2(a) Tus, whn th injction vv opns, highprssur hydrogn bns to owdown th 17-mm-ong injctor tb, forcing out a jt of niogn at was at rst in b rxing th niogn, th hyogn bgins owing om th tub, and graduy buids up to

prssur T rativ rspons of scirn to init jt of niogn d n to th hydrogn is

unknown, but it is c om th xprimnt pos at th ini jt vocity masurd by schirn photogrhs was chactristic of a owr prssur than ar xprimnta pros n an atmpt

to account for th gradu buidup to th injction prssur, a xprimnt pros wr shidby 03 ms om masurd tims, assuming ansit of th hydrogn jt through 17 mmong tipd buidup to injcon prssur rquird about 0.3 T ictd pnion rs wrgratr th masurd rats, but th agrmnt was btr for highr prssur injctions (3 Maand 3.82 Ma) for owr prssur injctions (1.86 Ma d 245 Ma) Prhaps highr-prssurinjction cass had ss ay tims in siting 17mm tb and racing injction prssurTs cacuaons w: again basd on 22 con g for sait tip

Discussion

Tis projct aowd an opportunity to appy J mod to air mixing whr concnation can b masurd T mod was vopd for is injcton, whr concnation is much mor icut to masur Trfor, is is intrsng probm Of cours,thr many rncs in th injction tcoogy usd for is and for hydrogn , and somof spcia aspcts of icting a comprssib gas rhr an incomprssib not handdby th standd J mod

T J mod was us in pricng th hyogn jt bhavior, ough r wr signictdirncs btwn th prictd and xprimnta pos for hyogn concnaon d hydrogn jt

pnaion Cn assumpons wr mad in both xpmnt computation work at woudndto b invsgatd r to dtrmin rasons for t irncs For xamp, xpmnt

masurmnts of hyogn concnaon ry on th assumpton at ighvocity jt has sammocu nsity, d rfor prssur, as static bomb T computationa work had to usassumpons about th rangmnt of hydrogn jt pro om pug ow wiin th injctor tp toa rouy Gaussian o outsi tip. so, computaons ignord osss associd wi shockwavs as hydrogn jt mixd with niogn Furr invsigation of s xpimnta dcomputation assumptions is byond scop of tis projct

Figur iusats why th us of spk pugs to ignit th hydrogn r mix on th dg of adirct-injctd hyogn jt is so icut T grain of concnation vry high, so at inspit of wid abii rang of hydrognair mixts, it is dicut to assur at spark pugis ocatd in a ab mixt Tat is, th cntr of th jt is much too rich to b, outsid jtis too an, and th rgion at contains propr rang of and air b is xmy now

Fhr, as in-cyindr r motion such as swir changs with ngin spd or o, pum mayb dctd such that spk is no ongr ocatd in a amm rgion

By going downsam om th injctor, graints in -r ratio ar ss svr, proviing a argrara in wich to ocat a spk pug Howvr, fr away om injctor spk pug is

ocad, t mor th pum c bnd bcaus of swir in th chbr A mor important objction tomoving spk pug r om injctor tip is at mor hydrogn woud hav to b injctd

into th chambr bfor raching th spk pug, and hi am sps of hydrogn gnray adto atc combuston

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Tere apper to be at lest two praches to resolving the problems ssoed wth spk plug locatond spk timing in e irect-injecon hydrogen engine. One apprach is to reduce e lame speed ofe hyrogen-air ixte, at est at e tme of the sprk. Te secnd is to very rapidly mix e hydrogenand r to a combustble mire over a broade regon is cen avlble.

Tere e several potenal apoaches to reducing e exemely high me speed of e hydrogenrixtre. Te ame speed of hrogen is pcully high at condions well rch of stoichiomeic,

peaking at < 18 (excess ir rao 055), and dropping off rapidly for el-len mixtures (Glassm1987). a emixed hydrogenir mixtre could be irectinjecd at about = 07 (excess ir rao =4) e peak ame speed wold be reduced by out a fctor of4 (relave to a < = 1 8 mixe) swould llow high power to be achieved when require, but might provie more stable ignion ndcombustion by avoiding e rich mixtures and high me speeds. wo ssible disadvtges of thisapoh re at it requires a very highpressre suly of ir nd e mxtre is en at a flammblemixtre rao in e injecon eqipmnt.

Another approach reduing e me speed would be to use erlycycle pilot injecton to provie ahomogenous el-len chge in e cylinder at equivalence ratio < of about 0.2 (excess ir rao of5) Te chge is ignited by te spk plug, nd the hydrogen is direct-injecte into e already brningmxtre lot injection would provide the energy reqred for lowpower operaton, d e direct

injected hydrogen would be used higher power levels. A vriaton of is proach ws receny usedby Koygi et . (1993) in which hydrgen was pre-ixed wit outside e cylinder at < = 02.ey otained excellent resul in tes of stable combusion d low N emissios. Ely-cye pilotinjection of a sml ont of hydrogen might hae some sfe advantages comped wit usingpremixed gases outside the cylinder.

It might so be possible to use a ch prechmber ad l main chamber as in some natural gas engines.In this case, a sml prechamber i a sprk plug is used wi a very rich ixtre of hyrogen. Tee speed is low, but still in te combusble range. Hydrogen is ire-injected into is pilo chber,and a sml ount of air enters e chamber aer e el is injected. Te sprkignited rich miepropagates a me out of e pilot chber and into e main hmber, hih contns a lean preixedhydrogen-air charge. is appoach is used for NO cnol

a number of natra gs engines (eg,

Aj-Superior).

A conention approach to reducing ame speeds is to use eaust gs recirculaon GR) gases. ish been done wi some success b Ninoiya nd Fha (1992) to reduce NO in hydrogeneledspk-igniion engines. EGR in hyrogen engines has the dvntage of never contning soot mateisthat cause problems in some hydrocrboneled engines.

Te second apoach to avoiding the senstvity to sprk-plug locaton would to rapidly premix acombusbe hydrogen-i mixtre close to e injector. One method would e to posion e spk plugso at the ound lead aways fces up into e hydroge plume, foing a reiclaon ne downseamof e ground lead, right at e srk plug locaton Tis should provide broader region of well-mixed

gases n lso help stabiie e me ner the spr plug. Te sie of e ground eleode migt beineased to to enhnce the mixing. A potenal disadvtge of any engine wi the spk plug loseto the el injeor is reduced spk plug lifeme because o ermal sess.

Summary and Concusions

An essentl par of ts effor was for SwRI personnel to become fmilir wi e progress made inhydrogen el use in intelcombustion engines through reserch conductd at Musashi I.. over e past

18


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20 or more yes Visits by SwRI personnel to Musashi , and vice versa accomplished e go ofsharing expeence with hydrogen els

Te gener sha of the hyrogen-air (acally hydrogenniogen) mixing as measured by Rayleigh lightscateng measurements was predicted by e J model, including bo axi and radi variaons.However, e modeled preicons of hydrogen concenon were greer an e measred vues and

the wid of e computed hydrogenniogen plume based on sclieren photogrhy was greater n thewid measured by Rayleigh light scateng Tese observaons indicate at eier e model or theexriments e not propey conserving mass Te expemental measurements of hydrogen concenationsuggest a signicany nrower jet e wid infered om e sclieren phographs. Tere e alsoanent eects of e hydrogen jet propagaon rou e 17mm distce between the injector vveand injector tip at e not haned propey in e J model wch was developed for a dieseltypeinjector where e vve is very lose to e injector tip

A number of suggesons have been developed dng this stdy to adress the exeme sensitity of thespk-ignition event in hydrogen-eled engines Some of these suggestions may be implemented in tureenne tests

Recommendatons fo Futue Wok

Hydrogen oers pomise as a el does not poduce geeouse gases Production torage dcombustion of hydrogen prodes numeous interesting research oppores Te roug ignition ofhydrogen in a spkignition engine is a problem observed at Musashi I in okyo SwRI has observede same rough ignion of hydrogen at some conditions in a ieselel pilot-ignited directinjected,hydogeneled engine Te high e speeds of hydrogen present unique chlenges to the combustionscientis Te discussion above ouined a number of aroaches to adressing e rough ignition ofhydrogeneled engines.

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Reerences

Furuma, S. and omisawa, N. (1991 ) Te Power System of a Computer Conolled Hydrogen Cr GH Injection nd Spk Igntion Engine wi LH nk nd ump, /MechE C430/028

Furuma, S. (1991) Hydrogen Engine echnology, 'R& at Musasi I.. , Project Hydrogen '91Conference Proceedings of A.HE p 1112

Furuma, S. (Jnury, 1992) ren of Soci Requrements nd echnologicl Developme ofHydrogenFueled Automobiles, ISAE Review Vol 13, No 1

Gassmn, I. (1987) ombustion New York: Academic Press, Inc. p. 1 37

Heywood, JB. (1988) Inteal ombustion Engine Fundamentals New York: McGraw-HilPublishing Co

Koyanagi, K, Hiruma, M., Hashimoto, H., Yane, K, nd Furma, S. (1993) Low NOx EmissionAutomobile Liquid Hydrogen Engine by Means of Du Mixture Prepration, SE 930757, Wrendle,

P Society of Automotive EngineersNinomiya, S, d S. Furuhma (1992) NOx Conol LH2Pump Hig essue Hydrogen InjectionEngines, Poceedings ofthe 9th Wor Hydrogen Energy onference Pis, rce, Vol 2, p 129130

Shapiro, A.S. (153) e Dynamics and Theodynamics of ompressibe Fluid low, Volume / Nework: Te Rond ess Cmpy.

20


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29/39

E Ccuate orice dischrge coecient, exit veoty, e mass ow rate, nd momentum rate of esource of e jet

F Jet rekup ccuaons (not used except for compson purposes)1. Breakup time nd istance according to Yue et .2. Breup time nd distance according to Sinnon et

G Ccuate jet e concenion, density, nd vecty at ri ocations at a given xi ocationRepeat ims in G un n axi distce is reached1 . Guess rge intia vue for centerine e mss action2. H jet reached e w this xi ocaon?

a Yes go to 5b No - go to 3

H Free jet Cacuate integrs for e mss ux conseraon nd momentm rate conservation, ndcorrespondng centerine jet veocties for ee jet om each of these conservation equatons

I

1. Does centerine ee jet veocity coputed om e mss ux cnservaon approx equ jetveocity om momenm rate conseraton?a Yes - go to 8b. No decrease guess for centerine e con d go to 3

2. If ths is rst time at is step, guess rge nii vue o centerine e mass action forwal jet Otherwise, iiti guess is revious vue om converged soution for next eieraxia ocaton.

3 W jet Cculate integras for e mass ux conservaon momentm rate conservation,and corresponing centerlne jet veocities for w jet for each of ese conservaon equaons.

4. Does centerne w et veoci computed om e mss ux conservaon prox equ jetveocity om momentm ate conseration?a. Yes go to 8b No - decrease guess for centerine e mss acion nd go to 6

5 Limit jet veoci to tt measured by ai et Ccuate sit me nd average veocity

between axia ocations.6 Ccuate e mss ux axi ocaon om conservaon of e mss ux for ee jet orw jet s appropate

7. Ccuate to mount of e injected to time () om (a) the mass ow rate rough einjector hoe, and (b) om summing up the mass ux at each i ocation Come esewo for check of compution of (b)

8. Wri peneaon data (tme, xi dstance for ee jet nd wa jet, centerine veocity, andcenterine e concenation).

9 Increment xi ocaon d check to see if beyond n i ocion.a Yes go to Hb No go to .2

Strting at rst xi ocaon, nd continuing to n axi ocaon, determine the e-ireqivence ratio ( at each raia ocation1 . Ccuate e hf width of the jet to e 1/2 veocity point.2. Ccuate e wid of the jet to zero veocity int, and dide into J number of equa

rdi ocations.3. Ccuate e e mass action and jet veocity at eh radi ocation for J oations at

one xi ocation

A-2


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4.

5.

6

789

10

1 1

For a givn axial location and raal locaon, calculat l mass ow ra rough annulus of wid B/J om consrvaton of l mass ux quaton Us quationfor a jt or wall jt as aropri for axil loconSum l mass ow rats through all annuli to gt tol l ow rat at axi locionMulply tot l mass ow r intgrd ovr all radial locations at on ial location byansit m for jt cntrlin bn axial locaons to comput mass of l in jt btwn

al locations XC(I1) d XC(I).Dtrmn lr rao d quivlnc ratio at ach rl locaon for a givn axial locaton.Wr out plot l for contours of qvnc rao Form sums that rprsnt mass of l in quvalnc rao bands K at a givn axiallocaon IUpda r location and chck to s all raial locions hav bn calculatda Ys go to H.1 1b No go to H3Updat locaon and chck to s f all al locons hav bn calculatda Ys - go to Ib. No go to H

J Sum up th mass of l in quiv ratio bd K ovr ax locaons 1 to I whr I varsom 1 to XSPM, total numbr of il stps1 Wt l nam cosponding to axi stp I "2 Dtrmin cumuliv l mass at quiv rato K for all locaons om 1 I3 Smoo cumulav l mass valus (MASC(K)) using 3 pt to 5 pt smoothing routn.4 Normz cumulativ l mass valus at ach quv ratio by th wid of th quv ratio

bds5 Wr quv. rato band cntr (PH()) d normlizd cumulativ l ms n that quiv

ro band summd ovr axi locations 1 I to ouut .6 Chck for mass consrvation7. Updat axil locaon to nxt ial location. Chck to s if I s at nal location

XSPM

End

a Ys go to b No - go to J

L. Functons1 Function DISCHR Cculat dischg co of injctor oric.

M. Subrouns1 . Subroun X21 Calculat ntgral 21 , for jt momntum rat consion2. Subroun XI33 Calculat ntgral 33, for jt l mass ux consrvation

3. Subroun 41 Calculat intgr 41, for wall jt momntm rat consrvation4 Subroun XI42 Calculat ntgrl 42, for wl jt l mass ux consrvaon.5 Subroun DEN Calculat air dnsity, piston locion, cylindr volum, tc as a nction

of angl (Not currny usd.)6 Subroun CYCLE Calcula bulk gas tmpratr om cyc smlaon (Not currntly

implmnd)

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Mathematica Deveopment of JTMIX Mode

T jt vlocity prol is dscibd by

(1

whr u is loc jt vloci, is cntrlin jt vlocit a vn axil locatio, f() = 1 and = r, whr r is locl rdius and b is radius of jt om cntrlin to th point whrth vlocity is ro. T l mss aon prol is simil th vloty prol but slighy broadr.T l mss action at any rdial locaon, c, is dsibd as

= (2)whr is cntrlin l mass acon and f() is sm as abov Ts prols ar shown inFigur A1

Free Jet Analysis

For th jt, consrvation of l mass ow r clld or in assumption 1) abov may b win(Sinnmon t l. 980),

[JcudA] 0dx

(3)

whr x is il distc, c is local l mass action, is locl jt dnsity, u is th locl vloci,and A is th osssctional ara of jt. ning 1 = 1 P I Pr whr P is th dnsi of or gass in chbr, nd Pr is th dnsi of th l, thn th locl dnsity is rlatd to lmss actin c by,

(4)

T crosssctionl ra of th jt is rlatd to th local radius r nd th nondimnsion radius by

an dirnal aa is n

Substitng Eqs. (), (2), (4), and (6) into (3),

d 2 L f(e e d 0 [2b PoUCm

dx m f(e

A-4

()

(6)

(7)


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VL

OF Y

Fgure A1 Radal dstrbuton of fue jet velocty and fue mass concentton

Now at the jet source (the ext om the hole), e el mss low rate s just

r = p usAs

where the subscpts s refer to ose vlues at e source Te n je velocty, u, s just

(8)

(9)

where c s e schrge coecent of the njector hole d s e erenl njecton pressureTe njector hole ea s

Terefore the el mss ow rate at the source s

but om assumpton 1 d Eq. (3), m m, so Eq. (7) s just equl to 11 , or,

2 .1 f(e)3e _ I 227b PoUmCm de - 7pfcD y 2Ain Pf d 1 m f(e)

A-5

(0)

( 1 1

(12)


33/39


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improve the wl jet odel Tere is so irare describing the interaction of a two-phase jet wi awl, but at is not penent to is discussion.

Te initi approh used here in eang e wall jet is to me similr assuptions to ose used in eee jet wi adjustments ae to the geoe fact, e ree assumpons listed aboe for e eejet were assued hold e for e wal jet, d e proles of velocity d el ass action were

assumed to be e sme as for e ee jet, with the centerline vues now assigned to e semines nextto the wl, d wi velocity and el ms action decreasing in e direcon away om the wl isapproach ignores e ction of e wall, and e resuing boundary layer next to e wll lso eini eort assumes impingeent normal incidence, ou impingeent at oer gles will haeto eated in e tre

Te wall geoey is assued to follow at shown in Figue -2 with he xi coordinate x'representing e distce ong e wl and the radial coordinae r' now reesenng e distance awayom e wl Te ea of he nulus represenng he jet at a gien i location x is

(17)

and since r' b'', where b' is the distance om the wl to the edge of e wl jet nd ' = r'/ henthe wl jet ea cn be ien s

(18)

and e dieren wtn s

(19)

Te cosevaon of the el mass ux of e wl jet is he se as e ee jet in genera erms, ie,Eq (3) except that the ii upper limit of integraon is ' = r1/b', where r is the distce om hemximum velocity point in e wl jet to e zeo veloci point

[fuA] 0 (20)but the values suitable for the wl jet must be substted ving

(21)

or pulling out e constnt terms to get

(22)

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:o

LL IMPNGEMEN MODEL SSUMPTONS

WLL JET

o TO 3o

A OI ORA CAA10

REE JET

bF, W

bFREE,w 13 bFREE, w

Figure A2. Schematic of free-jet mpingement with wall , and creation of wall jet

r - ' l p,


36/39

Eqating the mss x at ny oss-setion to that at e soe

(23)

so at in a simi way e ee etE.

(23) epesents e onsevation of el mass x d povidesone eqation with o nknowns e "enteline veloty 1 in this ase e veloit st otsi eond aye at e w d e "entene el mass aon dened the se point Againading e eqion fo et momentm ate onsevation ows he oppon to sove simteoseqations to detemine e two nowns

Te onseaon of momentm ate fo e w et is e sme in gene tes s fo e ee et

[pu 2d] = 0dx

Ssitng e appopate vales fo e w d simpiing gives

(2)

(25)

Bease the et momentm ate is onseed the et momentm ate y istne ong e w iseq to e momentm a of the soe wih is given y Eq (5) so

2 1 f(e1)4 2 2x 1 b 1 po um J de1 = pf (c0 2Ai/Pf ) d 41 mf(e1)

(26)

Eqations (23) d (26) e solved simtaneosly sing e sme nme poede as desed aovefo the ee et

Te soton of e ee et and w et eqations e independent of eah oe Te at poessetween a ee et nd a w et invoves a ompliated nsion egion that is not modeed sing thisappoh Howeve soving e ee et and w et independeny eqies that ini ondions eestalished fo e w et at may depend on e ee et Te est appoximation fo he inontions of e wal et e eny nde stdy Te lations pefoed to date have smed ate ini height of the w et in a ieon at ight ges to he w is identi to e ed adisat the ee et at axial loation oesponding to he wa is is ilsated in Fige A-2 Teini loaion of e w et ws ssmed to e 3 of e way ot om the enteine to e et

width at e wl shown in Fige A-2 Tis may e sted in wos at e ee et is ssmed toapoh e w d en open p nifomly at the w wi e mimm et veoity ose to e wwi deeasing veoity going otd om e w

Te aysis y Poeh et (967) sggests that e initi height of e wl et is mh ess h atassmed fo he alaons shown in is epo Ts e initi ondions of the w et wi poaye hnged t a moe oogh eview of e iteate is eqied efoe this hange is mae in emode

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Refeee M ata M Hioysu H nd Shiizu M (1984) "Disintegating Pocess d SpayChacteization of Fuel et njected by a Diesel ozzle" SAE naction Vol 93, and SE Papeo 840275

Belts S d Rajaam (1977) "mpingement of isymmeic Developing Jets" Joual ofHydaulic Reeach Volume 15, o 4 pp 311325

ida Hiawo K, d Sato G (1990) "Expeimental Study of ansient Gas Jet mpinging on aWl" SE Pape o 900479

Melton RB J (1971 "Diesel Fuel njection Viewed as a Jet Phenomena" SAE Pape o 710132

Poeh M suei YG and Cema JE. (1967) "nvestigation of a bulent Raial Wl Jet" oualofApplied Mechanic pp 457463

Sinnamon JF Lncas DR and Sene JC (1980) A Expeimentl d Anycal Study ofEngine Fuel Say ajectoies" SE Per o 800135

Yule AJ Miza MR nd ilipovic (1991) "oelations fo Diesel Spay Peneaon including eEects of the Be-p Zone" Poceeding ofthe Fh Inteational onfeence on Liquid Amizaitonand Spay Stem" HG Semei eito pp 267-274

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Nomencature

A ea of jet

As ea of jet at souceb dstance om jet centeine to point whee jet velocity is zeob dstance nomal to wall in wl jet between mmum velocty and zeo velocty

c local el mass aconc0 dschge coecient of injecto holem centeline el mass acond injecto hole diamete

I, el mass (kg) summed ove all aial locations and between i locaons and x+ 1 and sued ove l eqvence ao ands fo k to k+1x el mass ow ate (kg/s) summed ove l ad locatons at i locaon x andsummed ove l equivalence io bds fo k to k+1:1 see Eq (1) and Eq 4):2 see Eq (2)

:3 see Eq (3)n enne sed (pm) al istance swil ato in engneu local jet velocityu centeline jet velocity at a given ial locatonu jet velocity at souceu ini jet velocity at injeo tipx i dstce palel to ee jet isx' distce along wl jet plel wl

Greek Symbos

6_ lJ'spPtP3k

1-

P I Ptpessue deent acoss injecto holenomzed adi dstance om cenline of ee jet, bnomized istance no to wall om mimum velocity pont n wl jet, 'b'spay cone gle, wiout swi, between visu edges of spayspay cone angle wi swilloc jet densitydensity of e liqud eldensity of a o gases in chambeequivalence ato, o (ela)a / ()sihimiequivalence o imt associated with mixng pamete #1, :1equivence ato lmit associated with mixing pamete # :2eqvence ato limit associated with mixing pamete :3equivalence o fo the equivence ao band

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REPORT DOCUMENTATION PAGE Fo pprovOMB NO. 0704-0188Public reportng burden for this colleon of infomaton s estimated to average hor per response, icludng the tme for revewing nstuctons searchng existing dasources, gatheg and mantaning he data needed and completng and revewng the collecton of nfoaton. Send comments regarding this urden estimate or anyasect of this collecto of nfoation, includng suggestons for reducng this burden, to Washington Headquarters Seces Directorate for Informaton Opeations andRepots, 1215 Jeferso Davs Hghway Suite 120, Arlngton VA 2220202 and to the Office of Management and Bdget, Papeok Reducton Project (07008Washington DC 20501 AGENY USE ON LY (Lav ank) 2 REPORT DATE 3 REPORT TYPE AND DAES OVERED

1 994 Soa po

4 TTE AND SUBTTLE 5 FUNDNG NUB ERS

ydogn-A xng Evaao Rprog Egs () AW-2-1 22661(TA) FU421010

6 AUTOR(S)

Dodg ad D Nag

7 PERFORNG ORGANTO N NAE(S) AND ADDRESS(ES) 8 PERFRNG ORGANZATREPORT NUBER

Sohws Rsa nsSan Aoo Txas 78228051 0 DE94006950

9 SPONSORNG/ON TORG AGENY NAE(S) AND ADDR ESS(ES) 1 0 SPONSORN G/ONTOR

AGENY REPORT NUBENaoa Rwa Egy Laoao1617 ol Bovad NREP4256346

God O 80401 -3393

1 1 SUPPLEENTARY NOTES

12a DSTRBUTON/AVABLTY STATEENT 12 DSTRBUTON ODE

Naoa Ta nforao Sc U335US Depam of o5285 Po Roya RoaSpngf VA 22 61

13 ABSTRAT (mum 200 wor

Ts rpo psts ss of a opaoa sdy of a xg a yrog sg a spark-gd ydoge-fd egn T optaoss w opa w a ass g o dd a ss ns of Thoogy Tokyo Japa Th ydrogna xgwas dd a sag re ssvy of go o spak pg oo a spak ng drnd ydogefeed ges

14 SUBJET TERS

ydrogn fe hydogfd gs ydoga xng

1 7 SEURTY LASSFATON 1 8 SEU RTY LASSFATOOF REPORT OF TS PAGE

NSN 7540012805500

9 SEUR TY ASSFATONOF ABSTRAT

1 5 NUBER OF PAGES38

16 PRE ODE

A03

20 LTATON OF ABSTRA

Staard Fo 298 (rsribd by N

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