th"e'Sch~1 o:a ~~dU&~ ...

.,.

^{". -}

.•EEASIBILITY STUDY OF JET PROPULSION

FOR

REMOTE OPERATED UNDERWATER VEHICLES II.

.

. "-

@A

tf1~iSs;b~itted

^to

th"e'Sch~1 o:a ~~dU&~ ^...

Studiesinpa.rtial rul6ninent of the requireme~ts r~)f ~he d~ee^or ,;.. 'MasterorEngineering

•

~".

St.John'a

Faeultyor Engineering and Applied Science

.

MemorialUnlversit,.otNewtouadland

", July 1086

New,toundland

..

_Canada

'\ :~: .

' .,

- ,

i f. '

\

.

",. \ -,

)

.\<••.••..• ,.".,..", ... {"..{

ABSTRACT

TIbthes iJoaleuibiJity

~tudY

^01jetproP\llsic:i"Dror !emote

ope~~ted

^vebl-

\ .

ties(~O~l!I). \_~~Dupt01using a tiltiDItyplDozzlelor improved~~euYera- bili!,.isdiscuss.:Thoughthe pro p ulsion'effid enc101je~~1mcomparedtb

. ,

^":-

^.

^{- ' . '..} ~-""

that~r t~e..

pro l

let!lorthe veloeity~aDges.~~a~~eeeeunteeedin'R~.Vmove-_, meals',the

imple~eDtaUoD

or jd propulsionisconsideredin view01theadvaD- :•

ta~~" i~ ~~ProYiD'

\naneuveriD(

qu~ntie:ll. ~:

the iimplicitYof

~he Iy~tem

^aDd'

-lese

cO~~i~itY

ⁱⁿ

~~tlre com~eDsatioD ~ds ~o

^Its

ad~,~~t~ges,This

^study,'CoD-

.cedtrale!

on

^:t.he

lel~~~n

^{01anoptimumDonie}

CO·Dll.;;'U~tiOD tor 'RO~s.

.

~ ^,

..., .., ..__•

~*'n expe~tal

:set-up was.

desi~~

..aD.d lab ricated

r~r.

^this

inv~tigation

^.

Tendif!'ere~'plexi-l lau DieaJ_Doz~leswere.usedtor fivedifferentcirculardisk.

" .'.'.'i.'c cY '",·"·!'r7··.· ·"...".,

r'"';"'.: s.,'."."

,"" "fC""" '''''''. ''''. !-'.'''''.

-il-

'.

..I

-.j

;,~.

'-'l ':

r. j ~ . . .

.' .

~~...

.

..haped dra, platn-;.imula. gthe drag ofth~^{ROVmotionunderwater.Enerer} laues :ere deterrnimd

~~b·

.c:"cri: ent alI1 toDd

th~ret~~lIr. w~ ":. ":« ": e< "' ,;--'-­

:encounterl!d.in the

uperim~J.~ ~ ~;re ~mpe:ated

^{br towlnl the}modeHa " ,...

' .

\

^{.. " .}

:"'0 ;pe~

^{waterwave tanktorthesame}

r~Ie,

^{of speed..}It was fouadthat the

:

~rOPUbioO' ~Bjd"';

^b

mlX;~um \~r oo.p·arIl'~lar D~.il. ov~'.

^wid.

"D~

^{01 .:}

Ilow ratmencounteredia the npenmenb.FinallyIa feasibledesign of ajdptOo . .

p,U~ RO~'b~ijl\~111~' DO'iIee~ \presented'

^This

~~ign c~uld

be fabricated-.

and tested lor commercialproduction. . .

. .

^,

\

- . _\

. \

"

, \

\

^"

'-.. '.:.'

.: .

ACKNOWLEDGEMENTS

.This thesis wascompletedat"the Faculty01Engineering,MemorialUnlvee-

\. ' . '. "

sity 'of Newfoundlandanipa"rtiaUyrunded.~~ythe NationalR~e&rchCouncil or Canada,.TherecelpeorM~moriaJUniversityIellowship and graduatesUP~lemenl by the autborduring 'he

p~dod

⁰¹

~IU~y

^;,'gratel,ully

~'knOWledg~d, :

^\

. The~tborbgreat~y.indebt~toDr.H.~~,Kre,in,A.uociatep~oressor\( .Ocean .En.K.!0eering.,(orhis excellent!Uidance,:under1tandin~1 cooperatio~,ecn- '.tinuous support'and c;;erulreview

or

them.n~eript. ^{Thank!'aredueto} Dr. D.A.AJdr'ich,Dean

'~r 9r~duate

Studies, Dr.G,R..Peters;

~ean

^or

En~i'neering,

and Dr.

T oR.

^Chlhi;As90ci~teDeen of Engineering,ror tberaci.iiti~^providedand to the variousprores50llI.CortheirV&h.labl~.advieeandaugg~tions.

_ _ _~an k9are also duetothe Technicalstall' at the fluids lab,instru~entation lab,workShop,and draltsmeo,who madetheirsewl eeereadily'a!~ilable"^at"~Yery

•

8tag~otthis project.Finallyspeciaillianka ar.e due'to man)',oC· mylell~wstu-"

dente lor theirvelueble suggestionsand adviceduring.the course dCthis thesis.

" ~

,:,',,~;"".,";;"

'TA BLE OF CONTENTS

Page

iii vii xii xiii

.1

"I

.J

S', S S

•

8 '-^-10

•

·11

r: ^II

12 12 12

13 \

13 IS

• _, -_,~.~...;.' ·..i_.~'...

LIST OF SYMBOLS

CHAPTER 2 STATE-OF·THE-ARTANDLITERATURE REVIEW 2.1General

'-

.

'2.2State--or-Art 2.2.1Inlet 2.2.2.DUding 2.2.3.Wa~r-JetPump 2.2....NOIII.

. -

2.3'Advantactll andDisaduntagesorJetSystem 2.3.1AdYantages .

.2.3.2DiJachantages' 2...Principles"

or

Design.

" 2.4.1Thrust 2....2 EnergyBalun·

2.4.3OverallElIi,elene, - 2.6Objective.orPresentID,!e!tig~tiOD

ABSTRACT . -\

ACKNOWLEDCEMEd LIST OF FIGURES LIST OF TABLES

.CHAPTER 1 INTROD\lCTJON 1.1Gene!!!

.1.2

Score

o~-t~eIDTesLigation 1.3 Organisat ion

0 . '

thetbl!!lis-

'..' r·'· J:.~.oj"

'"

¹⁷

17 17 '17 18 lb 20, 200

21 21 22 22 23

24 24 '24 24 25 25 28

) 2.

34 34

-

34 35

35

-

35

-,

38 38 39 40 41

I

3.1General

~, ' " , ' , r ^{'c ' r ""}

CHAPTER 3RllVI;':W OF P\RFORWCE- PARAMETERS'

3.2 DefinitionofPerformanceParameters 3.2.1Ov~raJlEfficien'ey .,,)' 3.2.2.-Thrust Coefficient 3.2.3-Figure

or

Merit . , 3.2.4VelocityRatio (b/ 3.~.SReynoldsNumber

I\ , _ _ _

^If

3.3'Parameter! involvedin EnergyLosses 3:3.1Head Lossin the Nozzle\\

I • .3.3.2Loss,Coefficient

I .

3.4 Determinationof TheoreticalLoJ,es 3.6Determination of Experime'otalLOsseS .

, , 1 \ .

CHAPTER 4 EXPER!M£NTALORGAMSATIONAN!};

, TEST~ROCE~\i¥i ^\

4,1

a

euerel

' I \

4.2 ExperimentalSe~Up 4.2.1Test Set-Up 4.2.2ThrustPlateAssembly 4.2.3ThrU5t MeasurementSet-Up 4.2.4 Tct&1 Heaa.Mes.surementSet-Up

~4.2.5Materials 4.2.6Nanles 4.3ID!ltrumeDt~tioD

4.3.i Thrust 4.3.2 ,Flow Rate 4.3.3 LinearVelocity 4.3,4Tot/at Head

I 4.4 TestProcedure

4.4.1DataRecording

4.4.2 NoticeableProblemr/RecQmmeDdatioos •\ ,4.5-

~W;;er~t(ght

_,

,

^Join"

Fric'ip~'

^, Calculation

-c. .. .

wT~·~- .

'"

"

- yj-

CHAPTEt--~

EXPERIMENTAL RESULTS ANDDISCUSSION

5.1Genera! ~

.5.2EsperimenhJT&llkRes~l~

5.3 EnergyLossesin theNozzle 5.4WallEffet tCo~~~atedResults' 5:5Discussions

43 43 43 SI S5.

55

V

\

r ^,

_\,

,

^!

.1

'....

,.

~-:

CHAPTER • FEASIBLE ROYDESIGNWITH

·11LTlNG.TYPENOZZLES'.

8.1

General ' .

..' 6.1.1Oririnal~y.-Ol tbeROV design . 6.2Feasible

Rbv

design'

6.2.1'D~1PRequirements

\ r6.2.2RO~Componentl.

'0:1

~Q.Y ~tijrti..

^•

6.4

No~JCon~gurations

^-.

.6 .5 ~xperi.men~aJ Simula~ion

6.6Use ofexp erimental resultsin ROV design 6.7lJydrauJicSystem

1.. .

CHAPTER 7SUMMARY ANDCONCLUSIONS .7.1 Discu!!ion

7.2Suggestion. for future work

BIBLIOGRAPJ!Y AND LISTOF REFERENCES APPENDIX A

·APPENDDnl- •

.\ lOll 100 .lOll IQI 101 .~61 106 lOS

.m

113 113

12Q 12D 12.

121

126

·132

.;.:

. . : . ...

^{'. -)}

Fig. No.

. : '-:;~~" " 'l

LIST OFfiGURE;/

Title SchematicoCa ROY system

Schematic or Water-Jet Propulsion System tor ROV's

Page ..6

11

13 10

...!-

.:

..

~

SchematicShowing the'Region orExperimental

'Investigation /

_ . . j ..

4 Elevat.ion-ViewoCthe~xp~rimeDtalSet-.Up End-Vieworthe Exp,iiment.J

Se~UP

Water-Tight ROtatjig

J~int

^.

," ~.;

^f>

j .

Sectional PlanoCiLeverArmAssembly Drag Plates

US~

^{in the}Invest igat ion. Nozzle

Pro6~

^Usedin the In'tmigation

Pbotogra~ _.

_/ ⁰¹

~he

Set-yP With

In~trumentatioD

Thru~/PI.~tes.^"and.Full-BridgeC.ircuit 1

_2_ M~~U1ementofPressure

/ - £ "

hotograp~tilieWall·Effect Compensation 14 Propulsion Effidency Vs FlowRatiTerNo-Drag

Plate

.PropulsionEOieie1oy Vs FlowRatetor2D-cm Drag

_. Plate-

16 PrqpulsioD Efficiency Va Flow Rate Cor 24-cmDrag

I

plate

. ..

^~"

.

16

27 28_ 2.

30

3\

- -

-32 133

36

....

37

<4

45

46 \

•

- .

,-

-J i

58

61• 60

ss i -

52.. 53

-

⁶²

".-:-'

...

,.

~ Page

Propu lsionEfficiencyVI FlowR..~e~;m^{Drag 47} pla.Le

PropulsionEffi~ieDey^VIFlowRa·Leror 32-em Drag -48

plaLe •

; / -

Propu lsionEllieiencyVa Flow~Lefor 38-cm Drag 49

plaLe ·· _ _ '

HeadLossV,Flow~a.ie^Ior~l,^N2,~3,^{N4 . •} HelUiLQssVaFlOw RateIorNS,N6, N.71N8, NU.'

NtO" .

VehicleVelociLyV, Flow Rat efoI-2'4-cm'Plate '(Compensated~

Vehicle VelocityVaFlowRaLe;"tor 28-cm Plate .(Com p~ nsated) . .. •

~=~::::~ty^{VaF10r,Ra te for} 3~"cm^Plat,e

~ehiele

^{·VefocityV, FlowRate}

(Or

^ae-emp'late

(Compensated) ' .

Propu lsion Efficiency V, Flow Rat e fer NOP (~mpen,a~ed)• . P';; pulsion Efficiency V, Elcw Rate,ror 2D-cm 63 flat.(ComP!P&led)- ' ' -\ _ .

31- " Prop·ulsloD EfficiencyVI FlowRate ror'24-cm 64

Plde (Compensated).

Thrust Vs Vehicle Velocity for32-~mPlate' • 73

ProP}Jrsio~'

Efficienet Vs Flow'

Rat~

^{ror 32-cm "-'A6}

Plat.e(Cqm'p.enuted)•

7.

75 Title

~JirustVs~ebicle Ye'loci~yfor 3l}-cmPlate ThrustCoeD'i~ientve Veiocity Ratio

Efficiency,ve Velocity Ratio tor NOP (Campen- •76

sated) . ' , :."

EfficIency Va Velocity Ratio.for2G-cinPlate (Com- ( 77

pensate4)' ~_. 'k:;,. • . :. /

-,ix-

< ,

_P~.

Propulsion Efficiency Vs Flow Rate Ice'.2S:cm~ 65, Plate(CQ}np(!D~ated)

Propulsion Efficiency Vs Flow Rate r~r 36-cm 67

Plate [Compensated] - .'~

•.Tbrust~sFlow RaterotAll Nozzle3 ~

Thrust Vs vehicle Velocity for NOP 60

Thrust Vs VehicleVj!lo~tyfor 2G-cm Plate 70 Tbr~stVs Vehicle Velocity for2~cmPlate 71 Thrust Vs Vehicle Velocity for 28-cm Plate 7~

Fig. No.

?2

33

3.

.ss

3.

37 38_ 3.

40

.\ ⁴¹

42 43

44

45 Efficiency Vs .velocity Ratio tor24-cmPlate (Com: 'lB pensated)

4. ElJicif!ncy Vs_peosated)

'V~locity Ra~io·f~--2g.cm

Plate (Com- 7.

oJ':

47 Efficiency Vs'velocity Ratiofor32-cmp,late:(Com- ~O pensated)

48 Efficiency Vs,Velocity Ratio,tor ae-em Plate (Com- 81 penaated] :_/~

•.••1

fig.No.

'.

'49~

.Title

I . :~

Figure of Merit Vs Velocity Ratio for NOP (Com- peola,ted)

Figure of.M,eriCysVel~~iiyRatio for 2o-cm p.iate

(Compensate~) ^'<

Page 82_

83

52

'1 Figure of Merit:.Vs Velocity Ratio for.24-cmPlate

·(~mpensa.ted! . . ;

,Figure'of

~it

VI Velocity Ratio for 28-eo1Plate ....JColI)pensat )" . . ,

53 ' Figure of erit

V~

'v': locit y

R~tio

^{for'32-cm'Plate}

- (Compenst~) .., •

56

.7

~58

.'Fi~reof Merit VI Velocity Ratio ror as-ern Pla*

·(Compensated) - ' "

.Effi~iencyVI Reynolds Number forNDP(Compen-

la~ed) .

ElJieieoey Vs Reynolds Number for 2o-em'Plate

(Compensated) .

. '\

- -

·,r~~~ee::a~sd~eynOldsNumber for 24-'emPlate Efficiency Vs RefDold!l Number lor 28-em Plate (Compensated) _ _" . Efficiency Vs Reynolds Number for' 3Z·em Plete .(Compensated)

"

.60 Efficiency Vs Reynolds'Number'ror 36-cm Plate

(Comp,ensated) • '.~

..61-'··P~.Viewof..theRQVtD,esigned 62 -,

~levatioD.~View~r

^the'ROV Deelgned 63 Front-View.of theROVDesigned

,

.

^.;..{

. •..

'- -xi-

~F;g.No.

..

65

Title Non IeArrugem ent

OV ovemenLsandNozzle Position!.

Pale

, ...

.7

Hyd lie:Circuitror ROY 118

~~: .agramorHYdr~UlicCOntrolSystemtor

p

68

••

B1<*kDiagramcrco"ntrol

~y.stem

^{ror ROY}

Block.DiagramS~owing Paramete~sControlled

..

118

'"

,J,"'

^{•-; V.:.~.,}

( - , - . i1

....,.:

. ...:..

'

-

_-xii- ^{•" .>}

"\-

^{LISTOF TABL ES}

Table No. Title Page

MaximumEnergyLoss 07

Maximu mLoss Coefficients cs

Minimum Loss Coefficients oc

..

^{ComponentWeightsortheRq V 110}

~\

/

/

Ai Area ofjet CI Figure of Merit

,

-xiii-

LIST,OF SYMBOLS

Ch a tacter is t i~length(diameter) unde r consideration Friction -fact or

Accelerat iondue to gravity H_p Totalheadatthein le t

to

the noeate Hp. Head developedbr...!hepump H,

· ':~.,I?5!

in the system NL Energyloss,intheno zzle

L Nl

Totalbeadree.over~byinlet~

• 'i/

St atic head risefrominlettcdischarge Loss coeffici ent

Thrustcoefficient· Lengthof theeceel e Nozzle 1 (ex itdi..a.16 mm) N2 Nozzle 2 (exit dis.22 rom) N3 Nozzle 3 (ex itdia.30 rom) N4 .'NOiile4"(~xitdiG.~6rom)• N5 No zzle 5(exit dis. 44 rom) N8 Nozzle6 (exit dis.48mm) N7 Nozzle 7(exi~dis.52.8mm)

.\

N8.

p

• xi'v - Nonl~8 (exitdia.57 mm) Nozzle 9 (exitdia.61 mm) Nonie10 (exi.tdi~ ~~mm)

Experimentalresul t!Jor the":ii'onleundercon sidera.tion

T~eoretical

^{result s}

ror~~~e'~'~'~:;I~"u~de~ c~'n~deratioD

Peweeinp u t Q

R,

v,

Flowrat etbrougbthenozz~ ;<...

Reynolds

num~t~(

^V

~ ~:)

TbJ:Ust or the.nonle Velocity'undereoe elderetic n Vi Velocityo~theJet V. Linear veloc ityor thevehlel e '10 Overall efficiency-or thesystem • '1~'. Propulsionefficien cy of the,non le '1,.."" ·E fficiencyor the pump.

ii Overall efficienc)" neglecting thepumpefficiency Mass densit yor w'ater

Angular velocityortb~vehicle p

--= ..

A_lute~iscosityor~'a~

Kinematicviscosity,or water

..

--'

/

CHAPTER 1 INTRODUCTION

1.1 GENERAL:

The highcostofemploying'com~ereialdiversroeunde rwat erexplo~atioD

. - fa,

aodinspectionofpipelines',plaHor rns"andothermarineinstallations,bas ledto

- .

the development ol.remote ly operate dtunderwat er vehicles (ROV'a).Althougb'

;g'.;i~~S~f~~t;/:is;~h~' v~es a~e_aman

^and

lIlow-movin~,

^{tbey reach}dept hs ra rbeyonddiver'. (. capab ilities [14). Generally, divers reeeb

" to

depths lik;1500reetwber eee,tbe

. \

.

ROV 'sgo~ownanywh er e between6l¥lO~ 2~,OOOfeet"d~pe~d ingon~bedegree. of soph istication-0'1thevehi~.le1151,toperform'~,mplexcpereucee uunderwater min ing.

A number

..

ofsystims

.

8r eav aila ble tor

. -

'underwater

.

explor ation.The major

!

sys t emsinclude: . . .

-Wetdiving such83scuba,bounceandsaturat ion djving. I .

: " ,. /-, '

-One~tmospheremanned vehicles,with rnaoipulaton andcaml'!ru, eithertet .

ered.erautonomous. _.

..

_RemC?t~l~etittdvehi cles (ROV'a),withma~pulatorsand/orcameras. eiter tethered or untetbered.

or the abovementioned ayatems, remotelyoperat ed

'\

., : .

emerged'in thelastflveyeara as a domhianttool rorobae~atlonaDd- explratlo~,

"',.~'; ',.:" -.

, '"""

/ )

· 2 ·

or sub•.~;aD'reso urces(101,(211.The roilowingpropulsion-8y~emsarepreseotly,,in

. \

Propellers14.1driven by :, a) cue atmosphere electric motor.

b)pressurecompensated ,fluid-filledel~tricmotors.

c) pressure compensated hydreulie pumps end motors.

Water jets ta.!leinatedmao (or a long time

as

a means

0;

propub ion

or

eea-"

.

^.

.- '.

erene. However,

, it

~only during the last twodeeadt;Sthat it haareceived seri?us con,iderationin' fblpotentia1llland limitations as a meansofpropubiori. Water jets werestudiedby various authors (or theprop~ion

.

^ofsurrac~^marille~ crarb. in suchareuas theperror~lUl~eanalysis (201. hydrodynamic"designprinciples 129j,' applicationtf?highspeedv~els111,12). compon/ot stud>: 1231an~.exp~rimental a,Ddth~retica1investigatio.n(51.(7),1101,(111.Tbest at e--or· the-art(3),[261:and its practical considerations{71,181,(tl) were also dealt with in~tberstudies. ~

",Tb:re.arecircumstanci'ub~erwhich~a~erjets are.decidec;llyprerer.redover prop~lI~rs.These 1?c1ude:operation'ill.shallow~a~er;'high speed_crllrts~low noise levels, easymaneuverabi~~sed,weed and Ice inrested areas.Ourrent.reescneror waterj~.tptoPUlsio~^not'being •.doPted more.rreque~t1Yare: low overall efficiency.

high coot~rthe unit,'weight,'.an d space penalties.'Bypro~ermatching 'or the water jet.prOPUlai~.~unltto a given application, higherefficienc'ies a.reIeesible.

hr'

- 3-

J.I!'SCOPE

or

THISIN VES TI GA TION :

Though jets were usedf9f propulsionofmarinevehleles, itsapplic3tion to ROV propulsionwas not triedbefore.This'st udy is an outcomeottheP..!!ViOll!ll lack ofexperime ntalresults onandimmediate InterestiD.l,befe8.!libili tyatush,iga ,jet propu lsion

syste~ ror

small.' slow. movi,ngROV',

~hieh U~~Uid

^{for.. .}

itsmoveme~ts. ., ;" _ " ~. Theexperimentalstudyinthisinvestigationis aimedat studyingthe clreet-c .:rdifferentnosale

profil~'

^00'-

tb~

^propubionperformance

~nd

^{'rriv ing}

~t'

^the

opti:numDonie.The'expe;imeDt~1^set-upis designedand fabricated,takinginto accountthepu rpose of,t hisinve!ltigaiion.Teo'different nozzles of various conical

. .

profiles are usedan'dforeachece sle,thethr~st,tb;vehicle veloci tyandbead at _inletand exit are.meeeured for djlferent Dowratesth rou gb thenonle. Also, for each nozzle,~hesepara metersare measuredlo r dilferen td~ag^plates simplat ing thedrag ofth e movingvehicleunder water.

Tbe.'walleffect!! ofthe experimentalt~karecompensatedby towingtbe _.modei intbewave ta.nk.Alst. a designof ajet propelledROYwitbtiltingt;pe

nozzles ispresentedin thisstudy.

1.9ORGA1VTZAT;lON OFTHETHES IS:

In Chapter ·2 of tbiSthesis,a rev~eworthl!,jet propu~lonIYllte mis presented:Anexpressionis derivedtor optimu mefficieDc~or pro p ulsion ,negleet.

,"-

lugtbeiDle~bead.reeov~y.

ter

i ~xpl&iDstbe

^various

paramete~

^{and aninsight}

i~to t~"rierms

inol~edine~uatingtbeperfopn u ce.

hap~ deserib~

the ex;erimentalorganizatiopoCthethesis.Details of experi ntalHt-~p,testprocedur~andinstrumentationarepreseetedintbis

,::~ . ·_'h ". . .

~:: ..

^{. ,..} In Chap. , ;

5 , : l~' 'r:'~. ^{0 1 .; he}

expedm..",

;h'

dis....ion and':'0",..

f

o••• :'. . pariso~withtI etheoretic~ IOlution~ arepresented. , .

"In°Chapter

6,

a

Ce~ible

^{designoCannOVwithtiltingtypenoaelesisput.}

fcrtb .

,

Finally, thesummaryandeond usion'-o fthisinvest~gationB~epresented hi ,.'

.Cbapt~r7.

/

' 1.- _

t .- . _I ⁾

:

..

^~

. .

. 1

'.. . :

^r:~-":: ".,~~~^{" <,.}0'-.,,"

CHAPTERe

I

JJ.lGENE RAL:

Only dunug tbelut',"0d.,.J j.tp>Op u"lonw . .glvonecueider able

im~rtan~e

^{and ita}applicat ion

W~~i~&rilf

^towardssur faC1l vessels.Withthe

•advent of ROV'Sr i g,l),'jet eyetem wu·

~hOUl!iht

^of8lJa

me~~~ :r p~pulsi~D

^and

maneuverabilitY~~

^brierdescrip tio noftJ.ebasicelemeetelnvclved in

tb~

^jet

sy~­

ternis presen ted..

~erits

and' deme rits

or\jet

system' are dlaeuseed . AD exp(cssioll:

. I. ' •

isd~riv.edfOfpropuhion efficiency neglecting the inlet head recove ry.

e.e

STATE·OF-THE-AR T:

Mostwat~J'o'jet propul~ioDsystemsll.'Jemphasis ed....in)jteratu~eJ3J ,(26J,havethree basiceleme nts (Jig.2).The!~ere,,"

(i)ao intake

du~t

^which

i~ducts

^Ouid.from ou tsi dethe

~rart,

(ii,>ap'iim'piOrtraDs~iuing^eo'ergytothisfluid ,

J .

(iii)anexhau3'(duct.and 'noz!le which guide the jet or Buid·ouW4e.

T

.'J .:".,,'..,.-I:J.~·

-6-

Fig. 1 Schematic or a ROVS)'stem

130J

. - . j

'.,

....

. ,

·7-

"

- - - -- - - - .\

=---~-~- - - -- - - -

--- - -~--~-~-~._ - - - ---

Fig. 2 SchematicorWatel·JelPropulsion SystemlorROV'"

. .

_}',

~ ^... ~

^•.

^I

•

·8-

EvaluatioD orperrormaDc~ ehar~t~ristle!l^are~^{be eerried}out dep ending OD the pu tkular applicatlofl( 12f..

"f _ •

The iDletorscoop.locationdependsODthehulludwa ter-jttpropulsion;ys- tern eon 6 guratioo151.Them.j~rdesiploea tiooc<:I nsiderationsareinkeepingthe

. ' . ' . -

verticaldi!tances (whic::li,produce eleva tio nloss es) sho rt,keepi ngthe inlet immersed in watertopreventaeration, providinglullici ent waLer Bowtothe

_.pumpstoproduce the requiredthrust,andIpreve n tingorAdelaying the inception

oreavitatioQ.Goodloletsystem designrequireslowintero a llosi esand highre b-', teeeetcea~itatioDdurin gthe_tak~olfmod e endlow ext e rnal'dra gduring,crpise.

1221.Thesooop mustcap tureth etree stream do welliciently undera,range

o r

optt&ting conditions bet ween

_ .-

take-off&Dod'cruise.

Thlfli-eteffect.01cav itation,in"andarouadtbe1i1"d.istwoIold:

;,

j

(i)e,.,itat~~Dcan produc e aipifieanterosionoftbeiDletmat erial.

(iiic..,it a tion caa"degradethepumpptrfO rmaDcedue

to

e~ctS~iveiolet/ d iffuser head1~aDd, ultimately.completechoking of theflow whichItarvej.th~pump.

. \

De8nitiYfleyaluatioD orinle tperlormancer16)iDyolvesthedeterminationof .bo'; .Ili£ieallr 'Obe,weter

.~~be

';aptu,ed',

o,~~

^wha'

^':01;';

velod li:",;,Iet. .\ . ..

cavitationwlll-notslgnillcl ntly degrade tbb upturillg,aDd howmuch tbe bull

J

dragIa,a.f!'ed edbytb,p~eselleeof the Inle t.Itis pOlilblethtsom e leletdesigns could be low ininh mal lossbut bavebigbe~terna1dragell'eets.AD-Inletwith

;"' ';. ,e.'

.

,.~.

. g-

poorf1o~willexpe rience- II.,large energyor head1OS!J.A.wire~esh^to,~n^off thedebr isisdesir a bleinsomeapplicatio.Ds.

•.•.•DUC,INC..

Ina.water-j etpro~ubioosystem,a certain amou n tof,duetingmustbe

iosta~d' (22~ ~ove

^the

~lJ.te~om

^the hull i:n lettothepump andIromthe pump~^the~haust D~.zIe.~l~nctioD^ofth~d,uct.is.todeliver the correct quaot.ityofweter totheentranceoftheimpell~cieDtly(withmiolmumpres- suie 10ssl and::it h reasonably

u~irotm

^velO::itydistribution! and'to.erha u s tthe waterefficiently.Theefficie~yor the duet ing sys tem dependsODthe le n g thoC thepipe,numberand type oftr~~tions; ~nd^piperougbDess~ ^-r:

In general,aduct systemsbo~ld^beIjght-weigh~^{(incilldlngthe.}~eigbL^of water),havelow vibrati onlevels and low hydrodyn amic10S!l.ThelightDes~"aild~_

vibration levels depend onthe mltterialproperty.The 'hydrody namic.loss.;s-

.

_inelU

.' .

-

...

t

^{Jrietionlossesatlntem a l}duetin g walls,F~inglosses(pressureloss and rd,r ·'lo ss)Ie are..of

'r".iti~n.

OU' h. "ealergemeete ,·rootr.a<ti,"" ete.,and veloeiy profilesatsectio nsappro aehing the impellers and'statorvanes.

~ ..

....s

WATER·JETPUMP,

. • .f . ~-

The alnetion.otthepump in

aw~tljet

^system"isto

a.ecele"tatetb~

^sur-

rounding fluidmediumor increasethe eDergy orBow,therebyprodueingtht~at.

A pump with highmass,Dow rateand low bead p.erformanee I,a major I

".''"!l,;'.~"-,"1····.~ ;·.F"'., :, ."

--"j,.. .a l O-

~-~'"".:

. .

.

,;q~ireme~tfore8itie'ntoperation.However,ahigh.speedpumpwillkeepthe ',';dudsize.ut.d w!!iJb lof the

wa~rjll!t'!y!tem

^small.

.Thetypes ofpumpsutilisedby YlfioU;!propulsion syst;mdesigneninclude:

(i)centriCus al(~ad~al^flow).high~ead^a')dlow!p~ifie^speed,. (i1)mixedflow"{inclinedflow) -mediumheadandmedium specific~peed, (iii)uial flow(propeller) • low headandhighspedflcspeed,

.

.

, ^.

InROVap~lications,a.singlestage axial/ m!xedflowpumpofs?itable capa·

ci:;is usedtominimize'thesize andweight

o r

the vehicle"andincreMethepay·

loadc~~acitr.:..

t.f.4NOZZLE:.-

.1

..\

Non~esplay'avita..l'~i-Injetp~pulsioD&5a thrust~Djtby converting .

~~ential

^{nerO'intokinet ic}

energy~

good designof a

~olile 'depeDding

^on'its'

/

.. ' . .

^'-..•

^,

application (241, willI aereesethepro~ion'elliciencJ^oftheje~ consider~bIJ.

The fin;

~pect ~ t~ determiD~

^the

OPti~:m ~ea. ra~io

^{'for the}

~~~ed sp~d ~nd

then Itream liningthe'nonle toha.veaminimumloss. Inc;rtaincases,avariable

~re~

^{nOllle.isfoundtobe}

use~ul

^fora'Iarge.rangeorspeeds

,rc;m ,

talee-olI'to cru,~e~ .ijenff"testi~s

.

,ofaDozzle foraparticular applicat ionis'cOnsideredessen- _.tial.

, .' .. :.

~"

.. . :

'{~.:

\.,'", ,

l - ·

^-11·

' "

. .'.9ADVAN TAGES AN:DISADVA NTAGES OF JETSYSTEM,

'.9.1 ADVANT A GES,

(1) ForROV applicationswith a jet system,-1~9pressure compensat ionis required.Onlytheelectri~pump-motor need; tobe pressurecompensat ed.

(2)The jet'eyetemIs.muchsi~plerthall'the propeller.systemJ . (~pirectsteeriD~-a~dmaneuveringeentrolIrom the propulsor.ispossible.

(4) Forweedandfeeinlested ereesand Iorplaces01'debris, a jetsystem is the onlyal~Dati~e.

(5) Witha weteri et, itispossibleto"eliminate external underwaterappendag e".

(6) A wider ;hoice

o r

location01thepropulsionmeehlnerythanisnormally

ro~._ . .. . . .._ .

•(7!~liminationor complextransmissionmachinery whereri~ht..angledrives are required,such as in hydrolo il"crart s't m tpropeller applications.

. .

(81Possiblealleviat ion

. .

of underwater radiated propeller^~

.

cavitation noillethrough morecont rol over ca vitat io n,and removal or tbepropeller rromtbe,mainbody of. water.

(9) Detrimental effectsor propeller vibrationmay possiblybealle~iateddueto.

"

contr ol.?fthe.Jrnpe!lerinDoweb~ract~rillttcs^over~batof an open propeller.

(10) For lowing [remc velof debrisfro~underwater), thewaterj~can pr?duc,8 .greetertow.-ropepulls than aD.open propeller; however, a Kar tnozzle,

it

this

«, . ' ' , ' ,

regard,will be more efficient,

(

.:.'I"...^,~~.•.,.".,'

\ • es.«

DISADVANTAGES ,

·12·

_ .'.

::...

11)Ingeneral,awat erje t system will notbeas effiti,tDtu apropeller system,i.e., mor eboeepcwerwill be requiredtoperlorma partit ularIueetloawitba waterjet

~(2) Thepossibility01t!"'itatio n att~einletsyste!D tan advenely.alJet tperlor"

manteo This meansthat thereareseveralsources ol.t&vitationto be co.nsidered:

(3)Impellereceesscomparedwith ecnventicnalpropellerdesigns is poor.making

'Ins~~ttion,

^{reJ)alf ,}

~r ~emoval

01debris diffitult.

e.4PRINCIPLES OF DESIGN

e.4.1THRUST,

-.

From momentum principle, tb.ethrust of a walerjet isgivenby

T =p Q·(Vi-V,

I ~

^{pAi Vi '[I-(}

~; I]

. - ! .

where,

.Q~tl.owrate - AI'VI

T"'"'" tbru~~r~ueed.

p_ d~nslty⁰¹

th:

^81.114

Ai'''''areaol.t&ejet . J{f - velocity01thejet

\{_."""velOtit,.

o r

theveblele

(I ) (

- r; . j'

~13-

2..{.2ENERGYBALANCE:

The energybalance is obta ined.bywrit i.gBernoulli'sequation for a stream- Iiuepassing through tbe pump

HR+H_p_H, _ Hs⁼

-.vi 2,

²

where,

-,Hp ;",.head developedbythepU,mp

" V·²

-s.;

^{eO,ergylossesin thesystem=K}

^-i:g

^'.~_

HR

' ~,~am.ie

^bead

;eeover~d

a.t- inlet-=

~'(neg~ig,~~e

rorslow speed) Hs,.,.0 [alnce inletanddischargeareatthe same level) K.=loss coefficient

'9= acceleration duetogra vity

Thus(2) reducesto

Hence

V.' H^p =

1 ' + KI -f,-

e . ;

^{.sOVERALLEFFICIENCY:.•}

Theoverallefficiencyorthe water jetsyste misdefinedas

.

~'.

(2)

(2a)

(2b)

(31

:-:

-14-

where,

'10-=over~II,@!tiei@DCY oftheayst@m 'I,...,

=

^eff!eieDc101thepump

Substitutingrcr~T'and.'H'from equat ion.fl)And (2b)fbl)~tiveIY.we get

2 11 - ~I V.

;;=~=

^Vi

.'1, ...., (I+K)~i

\

where,\ \ ....

.lJ=

over~1I 'emcie:nc~

^{01 tbe sys}tem neglectingtbe pumpe:ffide ncy.

' . ". . . V .

Differen tiating equation(~)wit brespect'to(

V ;)

^{and equatiDS'ittozero,gives}

(')

. (S)

Substitutin~tbi!value01 V.I V,.into equation(:1),tbe optimu meffieiency becomes

I

••..··~=2(I + K I · ⁽⁶⁾

(negleding~.e.~lI'ed01inlet bead recovery}.TbiJ ,hows that tbeopti mum

efficlen~y

^{caD be}

O~ly a~ut

^50%U

b;~d

^{recoveryat Inlet}i.s^{neglected.Also, the} lower tbe loss coeffici«mtK,the higher tbe efficiency01propulsionwill be.

.rr

:-

c··....1l..,.: ^{:. ,":}

·15·

'.5OBJECTIVES OF PRESENT INVESTIGATION:

(i) To find theopti m um nozzle conflgura.tionCor slow moving ROY eppliea- tiODS.

{iii To provide experimental resultsQ~jet propulsion of small, slow- moving .ROV's, tbevelccitles not exceeding-4knots (Fig.3).

(iii) To arriVea~the energy loss in the nozzlebyexperimental and analytical me~ns.

(iv) To provide a feasible design or.a jet'P~dPelledROV with tilting 'type nceelee which could.be usedCorcom~ercialproduction.

. ,.,

:',->

(,

:

~"'.

r-

I

v;·

• 16-

)

.,

' 00a

REGIONOF I.NVESTIGATiON

I

•

VEHICLEVE~OCITY(V ..)"KNOT S _

Fig.~Schematic: ShowiDI the RegioD orExperim~DtallnVe9tigatio~

..;

,··k.,

_~

. · . .:..

...._~~~',i...;..;_:~:.:...;::....:..'.,-, _..~

'.

~17- CHAPTERS

REVIE WOFPE RFORMAN CE PARAMETERS

3.1GENERAL:

r :

The objective of this chapteris to show eninsightinto the various perfor- mance'paramete,rsrelatedto thisinvestigation.Also theterms involved are

, _ ' , ' ~·If

explalced~D~ ~,~ll~_ed.A support'jngdocumenta~joD(?rthe imeigylosses in the

\

nozzleisprovided. ."

, , I \

S,'DEFlNlT[ONS OFPERFORMAN CE PARAMETERS..

9~10VERALLEFFlcmNC~

The overallelfi~iencyorthe waterjet sys,temis defined as T V,

'10= pgQHp'1,.""

where,

'70";~yer.allemci~Dcy~orthejetsystem T= Thrustproduced ~

~.

⁼ Vehicle.velocily ). ,,-

p

=

Massd,ensity or the fiuid (water)=lOOOKg 1m3,

...

(7)

g

==

Accelerationdue to gravity

==

{I.81m/,2 Q

==

Flowrat e

H_p

==

Head developed by the~l!IYlP

-~

'1,...,

==

efficieIr~ orthepu~p

=

85%(1IIJ1Jum.ed)

Howeverin the experiment,sinc~~.thehea~developed was measuredat the entrytothe nozzle,a term called propulsioneffi~ieDcyof the ncssle'1,isIntrc- duced.Hence,

where,

(

TV.

'1,

==

pgQH, 11,_..., (8)

....J .

^H,

== He~d

developedat the

entr~

to the nozzle,

A termi1,which defines the overall e!ficiencyneglecting t'hepump'efficiency, istaken lor ideal.case'considering that thepump has 100%efficiency. This term is not usedloras perlormance parameter in thiswo~k.

s.e.e

THRUST COEFFICIENT;

/

T~eperrcrmeaeecharacteristi~sof water jetS shouldbe presented in dimension-

.

.

less,quantities, Thrust coefficientis onesuc~parameterwhichis,the ratioor the actual

thru-;;'m~uured

to the t-hrust which'wouldbe producedlorthe

Oo~

throughthe ncsale.Itis'deOnedas

(9)

,',

1.,\

., ~'" ~_- i_;~

,,'.1~

~19- .\

where,

KT= ThruM coefficient p= Mass densityqttbe 8uid ,. " Ai

=

Exitareaof the noeele

Vi= Velocityofthe jet

I

U.SFIGUREOFMERIT,

Figureof-meritisanothernon-dimensionalperformanceparameter,obtained by combiningJth;thrust/~orsepower'apd the jet velocityasrepresent edb~,

t5i

V'!i. ^1'~b

^is

independen~

^..of'

^{V i}

^{and the'pump;rpm}

~~.d

^{Jora given}

configuration; is essentiallyindependent_of the absolute value oft~e th;~stpro- duced.Iegeometricalchanges aremadein the model, suchas the

variatio~·,·

ⁱⁿ

thejetarea, the static performance

• . ^-

iscompar,ed

^.

o~the

^{. :}

~asisor't-he figure or

^'"

merit.Theoptimumconfigurationwill produce the maximumvelueor8gur~or

;.meritregardless or the magnitude orthethrust produced.The·lI.gur~or~e;~~is

•defined by theequation'\0

where,

.'C1= Figureofmerit P

=

Power input..

\

-

' ,.

."."",",,'.""

~_.

-._-~·20·

(IDa) C,-

[ (PAS~: P]

whici.'reducesto

'.1.4lrELOCIT Y RA TIO,

Velocity rat iois anot her nee-dimensionalparamete~whichiswedCor ecm- parisonoCperform ance betweenthe Dozzles.'l tisDor~allyused~ortheploning oCperformancecurves,The value.oU.hev:eloeityrati~'merely showsarela tion- ship betweent~evelocit~~tbevehicl;to thevelocityofthe jet and sinte,itisa

'ratio,the performanceof'the nozi les could"becompar'ea bythe use oCthis

p~r~~he

veloeit; ofthe

vehic~e

^ismeasured

~p~~eDt~IY

^{and'the\veto-, .}

-

c~ty"

^of

th~

^jetis

obtain~.bY kDOWil1~·t~e

^{flowrate..and:he}

exi~

^thenoz-"

zleCrom the relat ionsh'fp Vi

= A~ '

• 1

, ^{.'.'. 5}

REYNOLDS NUMBE&

Reynold,eurnberlsa non-dimensionalDumberwhichis'

a

ratiooCtbe~inerti!l Icrees to the viscousro;ces.Itisdefinedby

(II)

where,

v'

.. ) ..-," I...

:~

^...

^{,> .} ~ ^{__.. , .'} ~,

u · · ··

^:21-

d_f = Exit_' diam_. et eroftbeDozzle_/

- j

p= Massdensity ofwater =;:i<x>oK,

1m

S

:

II~Absolu teviscosity ofwaler/at15 Cebiul=l.J3g X10-.1Kg/m-.

Taking&I=pI p,thereynol d,num berbecomes

where,

) .,. •&I=_{)~ioematic.viseosity}ofwaterat 15 Celsius=1.139 X 10-0m 2/.

- - ^.

3.".PARAMETERSiNVOLVETflNENERGY LOSSES:

'-'.1HEAD LOSSINTHENOZZLE:

(118)":-

_ Thehe~loss in tbeeeealeai t due tovarioustadonlikefricti on.Thehvd lo:'!1~ec~a~occurswhenthere'illa

n o w

throughthe Don ie,Which.C::ODVet~. .thepoteoti~energyi~tothe kineticeDer~.Th~he~~loss,due tofr ictionis'given.,·

•byth e~Darcy.Weisbacb·e~uatioD

j

where,

H£;:: Headloss,in~he'DOJzI~ I' .

=

~ric~:loDfactor~pe~oDsurtace"rou~bnessandreyooldJDum ber (12)

- "

.

, .

^.

...,.: :.~~~;-: l

..t .j

.._.~1

...•4.'oJ.

' -

£..

L

= Length oftheboule

v, =

Velocityunderconsideration d= diameteroftbenon leunder c:onsideration

ss.e

LOSS COEFFIClt NT,

'The~ co~tricient.isanon-dimeusioealpar ameterandie&.ra}.in of:~he^:;.,

,

.

energy lossto the velocity head at the exit of theecaele-,Itisdefined by.

(K"

=.-.!!!:.-

i VI :' >"

I

where, r-~'~' ^.v

K= Losscoefficient - -HL=~Energy~,'in thenozzle

Vj~/2~= Velocityhead atthe exit ofthenozzle ..

.

'"

',1DETER MINATIONOF THeORETICALLOSSE&

(13)

',:

The tbeoretic~ros:se3in the nonle arede~ermined by~g 'Darey- We~hac:h'equat ion (12) byint egrat ionof cylindricalst rips across_t~elengthof

- " . . " .

the n03tle.The notzle.is dividedintos~ripsand eachst r!pillapp{Oximatedto a. cyli~derbytaklne.theaveragediameterover thesmailleogth.Thevelocityis cbteieedby knowiDP;thef1.o~ rat~.~d^{theaveragediamet er}

o f

t~e^stripundee..

C:OllSideratio n.

~umtos:

^the

'suri~;e"

rou'p;hoes5'(f=O.OOI ) rOt the macbinlop;

J~I .

r : . / •...

.

.

-..:.:

';:', -;."'.

,.

operationundertaken wiih polishing, and from the averagedlameterofthes~rip.

r

the relative roughnessEliiscalculated.Also the reyJIdfibnumberiscalculat~d for each strip and Ircm the moody'schart,.-tbef,ric'tionfactortOf)a~tripisfound

.- "-

and thenthe'Dercr -welsbecb' formulaisapplied foreach stripto'getthe energy

, '

loss fortlie'strj'Fin~lIy,^summationof these energ).iossesin thesestrips gives theove~1Ienergy loss in the nozzle underconsideration.

~

.-

~

A

co~pu'te~" 'program .

^(program

,

1 in appendix

..

Aliswritt;a~'f1.n(out~.

t~e

enetg¥ losses inthenozzle by integrationof the losses in the strips.and.progra m 2

.

^'

(in a'pendixA,lgivesth~.calculationof the lossc~ellicientsfrom th'etheoretic al loss in the nozzle.

9,5DETERMINATIONOF EXPERIMENTALLOSSES.'

• Theexperimentel Iossee are determinedb·yfindingthe totalheadattheinl«;t

•and at the.exitofthe nozzle and then taking the difference betweenthetotal head aUhe inlet and~he!bt al head at. theexit. ·Pie~o-^{electricpressureteansdue-} eraconnect edto'the pitot tube assemblyare usedtd~Ddthe total head aeeu- rat~lyuntilrepea tabilityis obtained.Program 4 (inap~end~A) gives the ealcu- lationr~rfu.ene~gylosses from the measureddata~btained r~omthe pleac- electric pressuretransducers.

"

'" ^{' \}

.r :

^'.

CHAPTERj

EXPERIMENTAL 2.RGANIS:'T10NAND TEST PROCEDUR_E

...

j.lpENERAL: .

~

.

"

' ~ :nae ~Xperime:t~ ~gr~~ wt.

^{designedwit.h}

_t~e

^{obj ective}of jov.elIUgati nK.

the use of water-jet,Propulsion.ror ROY applications.Thein~ueDeeof the various .par:meters

relat.iD~~be

perfo:maDceis teeognlsed

and

reported

in I'I'terat~re

.131.18),(21).Theexperimeri'talee....up··wu

d~igned

^!(Fig.lO)and

~uccessrully

^usedto

determ inetheperf ormaoc"eparimeten.

..

'

4.'EXPERIMENTAL SE,r;UP:

j.'1

,

TESTSET-UP:

... .

_ \Th••".

""' . p... 1....

r•r....

~gul.;

^{... k.r}dim••·. i••'l83cm '.l83crn,

:" .l~m}Figs...~ndS).A hi.lIbflowNtecebtrirugalp~mpand-tw2,.rotametersin'

.

. .

parallel (calibrated fortbeexperiment)are used torn.e~uretheflowwit h two sate

y~.!ts.,..DDe..b~low e~b ~t~eter,

^{tq.vary the Dowrate.A rotatiDgweter-'}

UghtjointI~a~~^atibe bottom'ofthe fixedverti calpipe.(Fig.6),and aD~:U:l~t the back,end

or

the leverirm are used:Thepum·pdraWl,waterrn:>~the tank

ud',disCbarJeSil,

I~to'

the lame tllDk through,,t he.ubmJ'ged Donie:thereby

'.•;. :_:-'.-:•.. .:::.~ ,.---,,~'.:~...,'-,.'.:~;- •.'.~!~.-...

l",".:

L

- 25-

rotat ing thewhole lever arm assemblyabouttherotating joint.Inth~frontend op t he lever arm,th'erp is a provision toputdifferentdrag plates-to simulate the dragorthevehicle underwater, There isa p'rovisionforreplacingthe nozzle by meansof a,screw assembly(Fig.1).Therearetwocylindrical l\uoyant fleets beneat~^{the nozzle}to compensa t eror the weightof theleverarmtoavoiduneven weight transmittedtothe rolatingjoint.

i.e»

THRUST PLATE ASSEMBLY, ,

,.Thethrust plates are held irom the top

o~

the experimentaltank

b~S

^•

of a fixtureandclempe.Th.

fi" ~':

^hcuees

'w;

b..msrunning aerosa'h;Yn'tb of the tank.Inoneof the beams, t"'!o holesaredrilledalligningthehol~illthe

~hrustplates k.··8x thethr~stplates by mean,"orboltswithoutany pfaY'.,Clamps are used8.!Jan auxiliary meansofsupport,

~:e, 9'THRUST MEASUREMENT SET·UP, (

\ 4..'

Thethrustpiateas"semhlyresemblesacant ilever beam andtbetbrust being applied tothe end of

th~aDtilever

^beam.

Th~

^deOectionex'periencedbY'the'·( / 'hM'

~I''r

^{are ..}

n~.d

^by

.~n

,ag" mounted

0;

th••

~rra"

or these pia,,,;

Thesegag~re'~Yen^&water proof coatingandcoeqeetedbyafull-bridgeeir- cuit

(Fig.~

^{that thereis}

~in imum

^{error dueto} temperatU!'ldifference betweenthesegagesand'sensitivityis'increased.The strain (agesare connected toa~ampli.8.erand in turntoa multimeterand anceehloeecpe.Theprevleue

"

calibration of thest rain gages in.termsorI~jl.dand strain-directlygives the unk-

~'n~wothrust, knowing thestrain developed.- -

i.e.iTOTAL HEADMEASUREMENT SET·UP,

l ' I

Apnct-tube assembly(Fig.12),is used (or themessl:lrelRentor total head at

..

t,heinlet and eX,it..or the nozzle.A fixture slides over the nozzle and grips it when

-

^.

^.

statiooary\Arod which holds the pitct-tube assembly'canbe.movedalong paral·

lei to the8.Xis~ortbe nozzlE;!.This facility makes.the measurement or the total head at the inlet and exit or the nozzle aloog the

'~entre-Iine-

possible. The pitot- tube assemblyisconnected to a piesc-eleeme pressure transducer, which in turn, isconnected to an amplifier, a multimeterand an oscilloscope. Previous calib'ra.

ti~n

of the pressure transducer in terms of'thepressure

and'volta~e di~ct

^gives

the unknown total bead, knowing the voltage prcdnced.

t.es

MATERIALS,

.Tberotati~gjoint and the lever arm~\emblrare made 'Of.aluminium.The pipe connections upto the fixed vertical pipe bolding the rGtating joinl are made or 2"

PV~pipe\Th.efixed vertical 2" pipe a.medeoCsteel.The drag: plates and buoy- ant'Boabareinide:of wood (Fig.S) and'PVC,respectively~T6e nozzles are made'

.

'

,.

oCtr8.011parent pled-glasll beeeueeof Ite advantages to.obse;ve'flow on cavitation,

..,JI

In,easymachinabilitYI,an~minimum surface roughness.

\ );.- .. .. . .

,

.

^',',.~

f '--

')

!:l

'"

GATEVALVE 12No lIN PARAL.L.EL}

PUMP' RO T AM ( TE R S

"1'2NOIIN

PARALLELI FLOWMEFicE S INTOONE

•

TANK

'~TE VALVE~-;~;'-^{- -_ .u -} ~- ~_^...~II

~ ~ ~ J~ J~ ~ ^OATOM

~,J,C), ",)"",),~,,,,,,,,i5h>iJ;;""»"'."")'

;-

,

''j

,

^Fig..( ElevA.tion-View or theExperimental Set-Up

~"\..

-

.~.

.

~.:.

JI

~ E

1 03

,. _-s

'0

~ ]

'"

^~

..

'"

~.

•.'•.• -••:"7""~': ":'''.~-I' ,·'-:

•2g.

-,

:

Fi~.·6

Water-Till;btRotatiDIl;Joi9t

/

/ .,

/

·f..

' (

J.

QUI)PLAT[

(~1I0W ~OINT

"

NOZZLE!lOI. DEIl

--iff--+"':'"

. "

Fi~.·7Seetional,Plan.orLeverArm Assembly

~

\

·(,...;:'." 1 , · '

r- ) I

)

·31 ·

03{28cmdio.!

04(2 4c mdiOi O~I~9~mdial,

MATERIAL'WOOD THICKNESS'15mm .,.'

!',

r

^';:'

Fig,8Drag Plates Usedin I.heInveil.igatian

. .

^'

^..

^;

~'~.~

^{••••• • <}- .',:,.'•... .>.

)

.. ~

~

1 - t - - -- - - - ' - - - j - -4---IH-\

-,NI ';' 2

N,

N4 N!5N8 N1 N.

[DIMENSIONSINrilln]

Fig.IINoz:d~Pro81esUsed in the Investigation

\

..

^~

..

-:

~

- 33-

Fig.10 Phot ographoCthe Set-Up WithInstrument at ion

I

t.e.«

NOZZLE&

NeaslesareCabricatedhom 75 mm diameter transpa rent-plexi-glassrod.Ten different conic alDoz:tl~cQ,llfigurationsincluding ecnverging, straight, an ddi~erg.

ing sections(Fi'g:9)were madeand"t es ted.In alleases, the inlet diameter

or

the nozzleand lenith'or the Dozzle were

,

fixed at52.8mm and.80 mm,

.

respec tively .^'"

The.first75mmiseon icel and the remain.jog 5mm~^Iistraightcylin d ricaleee-:

tion.Thb'is done toavoid the possible scat t eringoCthe jetandmaximise the

.

thrust.

^{. ...}

-

^-

,

^.

^,

;,9lNSTRUMENTATION,

;,9.1THRUST,

TemJ;'erature eompeeeetedstrain gages areprimarilyusedlor themeasurement01

tbru8~.

Two·different thrustplates85emxScmx O.6ernand85cmx sem'x 1.2em ,

\ -

,eachbousillglourstraingages areused(Fig.Ill"Th.elorm,erplateisusedCor thrusts lessthan40 newtor s,while.thelatter Cor thrustsgr;ate~.than40 newtons. The Cull-bridge

~i,cuit

^.withthe-s'train indicatoiii'employedforth.!,thrust meee-.

urement.The strain gages.aregiven a l!Iterproofcoat1ng"Previousea-'lbratioQof theSeg~.getiJl.ttDil;'

o t

loadanct't~ah~"^{dlreetlygivetheuekncwe}tbrust"knowing thein duced strain.The !riAion

~;

the rotatingjointisadded to thisobserv ed thl'Wlt'togive

th~

overallnet thrust of thenozzle.

. f •

, .

· .

_-35-

'I

, ~ --

TheRow ratesare measuredusingtirercrerneterahrparallel .Theseare calib r ated in termsofvolum e Bow(cubicmeterspersecond).The flowrates are var ie dby

v : ' ,'

: gate:'valv es; o,e p?Sitioned below eachrcnmerereois-10 have iDde~deDt operation.

4.9.'LINEAR VELOCITY ,

./

.The angularveloci tyisliPstfound byDoting

th~

^{,ti m etaken}for a.d'eftn!tenumb:r of rotationsby.us'joga stopwet ebco;rect

to oo.e.:~undre~tb

^ofII.

$eco~d.

^Know-

, ....·jo g ther~diu!(Iengt.b)of thelever arm,thelilleat'velocityiscalculated,u singthe

,

relation:

'. ' : \ Ii '

Linear ve\Qeity=Angut:a.r'velocity xra d ius o!J!::'e£ml

4.9./TOTAL HEAD, _,)

The 1,'otalhead at,theinlet of tbeJlonleismeasured using" plt~t t~~eassembly and pleeo-eleetrtc pressur'etransducer(Fig.l"zj:-TheelectritaisigDal (output) or thetran s d ucerisamplifiedbyanampli 6 e r and thenobservedin•multimeter and·oseillOWlpe.(evOlts).The

~revious

c'.Iib;:}..o.nof the pressure traudueerIn

.' .; ^-

' . ... . .

terms~r~pressureandvQltage directlygive theunknownpr~ure(or..theto~al head), knowingthev~I~~geproduced by thetr'Dsduc~.

J ; ;

·36 •

-,

-.]

Pl.ATl2 jovl:"••"'

'P!.UEI

-rwteCl( ttl

+

.

r l ;

_.'

·,

tFig.11 Tbr'llstPlatetand Full-BridgeCircuit

I

<,

. ..

^'

.>

/

. /

\ .

•

I

/ ^"

^{....• "._"}

^..

^'"'-

"

. ...

c-

- 38·

/'/ TEST PROCEDURE:

.The.tankis'filledwith water to a particular,~evelwhichis maintained

"throughout theexperimenialst udy.-However,thenozzle and the drag plate were

fixed before filling up the lank. The thrust plateispleeed,against.t he trontrl1C~

.or the drag plate tor thrust measurements CordifferentBow rates. With"t~esame .arrangement, the total headis meesured 'at inlet and exit

or

the nozzleusing a

P'i~~

^tube.For

v~;ocity

^.meaSuremenls,·tbe thrust'plat eis'removed add

th~

us'mbly.i5aliowed to'rotate simulating the motion or the

v~bicle u~der

^water:

-The w;1I elects

ar;

't hen compensated.

. "':

^"

. ^{" \J ~ , ,' .}

,H I DATA REC,.,DlNG:

All the^• instntments are turned on 30 Iitinutes^",""

.

^{•- J'} b~roreeach test to,allow&

warm-up period. The caps

or

tbepiezq-el~ticpressuretransd~cel1areremoved.

eleeaed with cottoAJswa~s,.dipped intuner degreuer andre~~ppedeach time ..

ijley a;e mounted through a 'brus holder.

G~at ~are~

taken in mounting't.he ,mic~ot.cOnD~~OI1toth~pressuretrani~ue.er.lleadampliD.~r3u the slightest amou,~ ~rdirt or bumidity near the connedion.'or a twist in the ecaneetcr,pro- deeedi.drilUDgO~put^voltage;Tbeoutput of the charge amplifieris fedto the

. ' .

^{~ .}

multlmrter:an osellOilcope, and a,pl.otter.Tbe straing~gesereecnneeted to the

"raia. indicator..T'Jp pie*electric preeeuretransducers and the atrain gages are

. '"

,-. ' . ^"

.

^.

calibrated10t,lia~}hevolt"agemeuu~mentsdirectly give.the thrust or the total

h'~" /

,

"

,. b '

\ . ' _

'"

\' .,...~",:Ji.J.....

\

·3g·

...

,..•^,:.~.

. ,.

With tbe thrust plate againstthedrag plate,tordifferent!low rates as mees- ured by a rotameter, -t he strain lndicatcrreadings are Doted down.Aho withth e pilot.tube a.ss;mbly,the total bead atthe inlet and exitom-enoarleismeasured

(,, ' . :J

using aping-electricpressuretransducer. ,

.The angular velocityiemlt~.uredby a stop watch ecereetto one-hundredth ora second.l~

, oj@ t

to checktherepeatabilityortheresutte,_ea~bparameter_i~

measuredatleas\ ten times

und~r

^{similarconditionsuntil}reasonab,ly consistent values(witbin 10%) are obtained.

4.4.'NOTlCEABLE PROBLEMS/RECOMMENDATIONS,

In general, therewas a verygoodconsistencyin:thetbnJ9t and total head -meeeuremente witbinthe range or10%devi~tioD.The averageorthe readinpis takento'be the final value,Alsothetemperatureofthe wetetueed duringthe experimentalinvestigationwas around 15degrees celsius,

,

...- -

C~'rtainprobl~~ommendatlons^noticedindud~:

(i).F~equent , removalandmoun~ing-orthe thrust plat es andpitot-t ube assembly

made it amust.~v,ickon to thesmallexperimenta~tank.

(ii)Alsot~e.water-t igbtrota~iogjointneedsto be removed and gr.cased at the st artofth~^{experimentsotbat}the frictionisalmosttheeemeas whencalibr~~cd,

- -

. '~

(iii)Tbe'use of a!lo~C.motorcouldbe avoided ifaDCmotorwu availab,le;t~~.~' results in deadyr~mthroughoutthe course oftheexperimentirrqpe<:~lveofthe load fluctuations.

(Iv)Theout putor.thepieao-eleetrlepreslll ure transdueen IOmetimeaIhootlup

" ,,' ,

.

^{'~.; .-....}

,;-.~' ',<,.'

V_j= Velocity

ot

the jet'

" 40·

I

and muchc~reis to be taken to get.epeatabilityand consistenC;a,-",,S'oabo with the strain zagcs, where fluctuatiODs are"quite unavoidable.

(v) T;th'ust

~C

^{the noarle}isto be applied gradually so thatthest ra iDreadings are noterroneous.

4.5'WA-...rER:..TIGHT JOINT'

F~ICTfoN CAL~ULATION

^..

The Criction oCothe'water"tight

\.

rotating jointis Cound experimentally,The

,

, ' .

^,

dr~gplates are removed trom tbee~doCthe lever arm assembly and theeseem-

.

,

-

-/<~

^blyis left stationary.

Th~

flow through the

~'Oiz1e,is

gradually increased until the

leve~

'.arm assembly

jus~

^startsto

'F~ve

at a steady miniJllllm sp'eed.From the

, 0 , I

ft9w rate,knowingthe area of tbe jet (same as the exit area of the noz·zle).the thrustiscalculated using therela tion:

where,

.. T= Thrustproduced by the nozzle p= Densityo(l.b~uid(water) 'A j.= 'Area of tbe jet

,

t

^This

th:st~hOUld

^{be equ'al}

~·the,.rriaion

at the'joint.It is.observed tll:at rorBC?w tate or9.Il X 10--4m~/",rorjhe jet area. or2.01

x

^10.4m²,tbeessem- )

.bly

m.~'!.f'

^••

'~&dY

^{speed.From.lb... .}v.I.",.'.I"iritl\iolound 10

~e

^4..12jI

Newlon.. ,. _ ,

, ~-

. '

^.

J

. .