LA OLA ISSUE 23

SAGARSANGOL KAR

SAGARSANGOL KAR

DI SCLAI MER Thi smagaz i nec ont ai nsi nf or mat i on obt ai nedf r om aut hent i candhi ghl y r egar deds our c es .

Reas onabl eef f or t s ha v ebeenmadet opubl i s hr el i abl edat a andi nf or mat i on.

Reader ss houl dnot e t hatt hewebs i t esus edasr ef er enc ema y c hangeov er t i me.

Thi smagaz i nehasbeen pr epar edpur el yf oreduc ai t onal pur pos e anddoesnoti nt endt ohur tanyper s on ormat er i al , whet herl i vi ngordead.

I nc as eof anymi s t akenot i c ed, i ts houl dbe wr i t t ent ot heedi t orf ors ubs equent c or r ec t i ons .

Al l r i ght sr es er v ed.

Nopar tof t hi smagaz i nema yber epr oduc edi nany ki ndof f or m wi t houtwr i t t enper mi s s i on f r om t hec ompet entaut hor i t y .

CONTAINERISATION

Containerization is a m ethod of transportation of goods using interm odal containers. The advantage of using the interm odal containers is that they can be easily used over various m odes of po tation like freight trains, trailer trucks etc. transpor Handling of cargo becom es easy with the use of containers. It reduces the risk of dam age to the goods and offers safety from theft. These interm odal containers have a standardized size. Container Term inals are located all around globe to handle the containers using cranes and forklifts, which m akes the work m ore fast and efficient. It also reduces congestion at ports as it takes a fixed am ount of space.

PROPELLER DESI GN DI GANTA GHOSH

P r o p e l l e r sa r ed e s i g n e dt oa b s o r bmi n i mu mp o we ra n dt o g i v ema x i mu me ffic i e n c y , mi n i mu mc a v i t a t i o na n dmi n i mu m h u l lv i b r a t i o nc h a r a c t e r i s t i c s .

T h ea b o v eo b j e c t i v e sc a nb e a c h i e v e di nt h ef o l l o wi n gs t a g e s : 1 .B a s i cd e s i g n 2 .Wa k ea d a p t a t i o n 3 .D e s i g na n a l y s i s

1 .Ba s i cd e s i g n B yu s i n gs e mi e mp i r i c a lme t h o d s( i . e .s t a n d a r ds e r i e smo d e l p r o p e l l e rd a t aa n dc a v i t a t i o nd i a g r a ms )a n ds i mp l eb e a m t h e o r y ,s t r e s sp r e d i c t i o n ,t h ed i a me t e r ,p i t c h , b l a d es u r f a c e a r e aa n dwe i g h to ft h ep r o p e l l e ra r eo b t a i n e d .

2 .Wa k ea d a p t a t i o n B yu s i n ga n a l y t i c a lp r o c e d u r e s( e . g .v o r t e x o wb a s e d l i f t i n gl i n eme t h o d s )a n ds i mp l eb l a d es e c t i o nd e s i g n me t h o d st h eb a s i cd e s i g ni sf u r t h e ro p t i mi s e d( i . e .p i t c h d i s t r i b u t i o na n ds e c t i o n a lb l a d es h a p e )wi t hr e s p e c tt ot h en a x i a lwa k e o wi nwh i c ht h ep r o p e l l e rwo r k s .

3 .De s i g na n a l y s i s U s i n ga d v a n c e sa n a l y t i c a lp r o c e d u r e s( i . e .L i f t i n gs u r f a c e b a s e dme t h o d s ) ,t h eo p t i mi s e dd e s i g ni sa n a l y s e di n3 D wa k e .I ft h ea n a l y s i sd e mo n s t r a t e su n s a t i s f a c t o r y p e r f o r ma n c eo fc a v i t a t i o nh u l lp r e s s u r e s ,s h a f tf o r c e sa n d mo me n t s ,b l a d es e c t i o ng e o me t r ya r emo d ie db yt r i a la n d e r r o ru n t i lt h ep r o b l e mi ss o l v e d .

LA OLA |AUGUST 2017

Pr o p e l l e rDe s i g nBa s i s T h et e r mp r o p e l l e rd e s i g nb a s i sr e f e r st o : i .P o we r i i .R o t a t i o n a ls p e e d i i i .S h i ps p e e d . t h a ta r ec h o s e nt oa c ta st h eb a s i sf o rt h ed e s i g no ft h e p r i n c i p a lp r o p e l l e rg e o me t r i cf e a t u r e s .

Re s i s t a nc ea ndP o we rE s t i ma t i o n As h i po wn e ru s u a l l yr e q u i r e st h a tt h es h i pwi l la c h i e v ea n a v e r a g es p e e di ns e r v i c ec o n d i t i o n( f o u l e dh u l li nf u l l d i s p l a c e me n ta n dr o u g hwe a t h e r ) ,V ,a tac e r t a i n S E R V I C E e n g i n ep o we r .I n i t i a la c c e p t a n c ewi l lb et h eb a s i so f d e mo n s t r a t i o no fah i g h e rs p e e d o nt r i a lc o n d i t i o n ( c l e a ns h i pu s u a l l yi nl i g h td i s p l a c e me n t )V a ts o me T R I A L p o we r ,i . e .

VTRIAL = VSERVICE + δV h g u o ,r l l u dh e l u o ef h ot et u ed s a e r c n di e e p es h st Vi eδ r e Wh . t o n s1k na e k a yt l l a u s su di n ,a s t c ffe re e h t do n ra e h t a we e t a t ls l dwi r a y p i h es h dt n ra e wn po i h es h nt e we t e tb c a r t n o Ac e n i g n ee h ht t wi eV v e i h c da l u o h ps i h es h tt a h t AL I R T r ro we o sP u o u n i t n o mC mu i x sMa t fi %o 5 ,8 y a ,s g n i p o l e v e d ) R e( c n a t s i s e sr e c n a t ms u c r i ec v o b ea h rt e d .Un ) R MC g( n i t a R g n i r e v o c d( e e p fs eo g n a rar o )f P r( we o ep v i t c ffe ee h dt n a E d o h t eme t a i r p o r p p ga n i s du e t ma i t s ee r )a dV n a V E C I V R E S AL I R T t s e lt e d rmo ,o a t a sd i s y l a n la a c i t s i t a t rs ao t a sd e i r e ls a c i . n o i t i d n o lc a i r nt ri we o ep v i t c ffe ee h st i sP i h .T s t l u s e r E s )i P n( o i t i d n o ec c i v r e ns ri we o ep v i t c ffe ee h T E C I V R E S E t a h ht c u ds e t a l u c l a nc e h t

PESERVICE = ( 1+ x)PETRIAL wh e r e( 1 +x )i st h es e ama r g i nt h a tt h es h i pr e s i s t a n c ei s i n c r e a s e du s u a l l yb y1 0o r2 0 %i na v e r a g es e r v i c ec o n d i t i o n s .

S e ama r g i ni sd u et ot h ee x t r ar e s i s t a n c eo nt h es h i pc a u s e d b yf o u l i n go nt h eh u l la n dp r o p e l l e r ,we a t h e r ,wa v e sa n d wi n dc o n d i t i o n s .

LA OLA |AUGUST 2017

T h eUs eo fS t a n d a r dS e r i e sDa t ai nDe s i g n De t e r mi n a t i o no fOp t i mu m RP Ma n dP r o p e l l e rS i z e ( Di a me t e r )( Ge n e r a lC a s e )

T od e t e r mi n ea no p t i mu mr o t a t i o n a ls p e e dN ( R P M)f o ra p r o p e l l e rwh e na b s o r b i n gc e r t a i nd e l i v e r e dp o we rP a n da D o p e l l e rd i a me t e rDi na s s o c i a t i o nwi t ht h es h i p s p e e dV . p r S r o p e l l e rt y p ei sc h o s e nd e p e n d i n go nt h es h i pt y p e , i )P x i mu me ffic i e n c y , n o i s er e d u c t i o n ,e a s eo fma n o e u v r a b i l i t y , ma i t i a li n s t a l l a t i o nc o a s t ,r u n n i n g c o s t ,ma i n t e n a n c e i n e q u i r e me n t s . r i i )N u mb e ro fb l a d e si sd e t e r mi n e db yt h en e e dt oa v o i d h a r mf u lr e s o n a n tf r e q u e n c i e so ft h es h i ps t r u c t u r ea n dt h e ma c h i n e r y . i i i )B A Ri sc h o s e nt oa v o i dc a v i t a t i o no nt h ep r o p e l l e rb l a d e s .

L a r g e rt h eB A Rr e s u l t si nl e s sc a v i t a t i o ns u s c e p t i b i l i t yb u t i n c r e a s ei ns e c t i o nd r a ga n dh e n c eal o s si nt h ee ffic i e n c yo f t h ep r o p e l l e r .B A Ri si n i t i a l l yd e t e r mi n e d . i v )F i r s ti ti sn e c e s s a r yt od e t e r mi n eame a nd e s i g nT a y l o r wa k ef r a c t i o n( wT)f r o me x p e r i e n c e ,p u b l i s h e dd a t ao rmo d e l t e s tr e s u l t s . v )A d v a n c ep r o p e l l e rs p e e dV Ac a nb ed e t e r mi n e da s V =( 1 wT) V A S v i )D i a me t e r so fb e h i n dh u l la n do p e nwa t e ra r ec a l c u l a t e d a sD i sa s s u me d t ob eu s u a l l yp e r c e n t a g eo ft h ed r a u g h t ma x D =D =a T ma x B a <0 .

6 5f o rb u l kc a r r i e r sa n dt a n k e r s a <0 .

7 4f o rc o n t a i n e rs h i p s wh e r eD a n dTa r et h eb e h i n dh u l ld i a me t e ra n dd r a u g h to f B t h es h i p ,r e s p e c t i v e l y .

BASELI NE

LA OLA |AUGUST 2017

Wh e nt h ed i a me t e ri sd e t e r mi n e dt h ed i a me t e rs h o u l db e a sl a r g ea st h es t e r no fh u l lc a na c c o mmo d a t e ,t oo b t a i n t h ema x i mu mp r o p e l l e re ffic i e n c y .T h et y p i c a l g u r e so f t h ec l e a r a n c e so fp r o p e l l e r h u l l ,p r o p e l l e r r u d d e ra n d p r o p e l l e r b a s e l i n es h o u l db e : X 5 %t o1 0 %o fD Y 1 5 %t o2 5 %o fD Z u pt o5 %o fD T hi sDB s ho ul dno te x c e e dt hel i mi t so fpr o pe l l e r hul lc l e a r a nc e s v i i )Ope nwa t e rdi a me t e rD0 i st he nc a l c ul a t e db yi nc r e a s i ngt he DB b y5 %a nd3 %f o rs i ngl ea ndt wi ns c r e wsr e s pe c t i v e l y .

DO=DB/ ( 1 0 .

0 5 )f o rs i ngl es c r e w pr o pe l l e r s v i i i )T hi sdi a me t e rD0 s ho ul da bs o r bt hede l i v e r e dpo we rf o r t r i a lc o ndi t i o na tt heo pt i mum RPM whi c hwo ul dc o r r e s po ndt o t hema x i mum pr o pe l l e r e ffic i e nc y . i x )F r o mt heP o we r S pe e ddi a gr a m( PE v s .VS)PETRIAL i sr e a d o ffa tt he VSTRIAL 12000

10000

PE( kW)

8000

TRI ALCONDI TI ON 6000

SERVI CECONDI TI ON

4000

2000

12

13

14

15

16

17

18

19

VS ( Knot s )

LA OLA |AUGUST 2017

x )P r o p u l s i v ee ffic i e n c yη Di so b t a i n e db yi t e r a t i o nf o rt h eo p t i mu mR P M,N .I n i t i a l l yη Di sa s s u me d( i . e .η D ( a s s u me d ) =0 .

7 )a n dt h ed e l i v e r e dp o we rP Di sc a l c u l a t e da s : P D ( T R I A L ) =P E ( T R I A L ) / η D ( a s s u me d ) x i )B pa n dδv a l u e sa r ec a l c u l a t e df o rar a n g eo fN ( e . g .N =8 0t o1 2 0 ) x i i )F r o mt h eB p δd i a g r a mo p e nwa t e rp r o p e l l e re ffic i e n c y , η 0i sr e a do ffa tt h ec o r r e s p o n d i n gB p δ( D 0 ) x i i i )N ( R P M)v s .η 0d i a g r a mi sp l o t t e da n dη 0 ma xa n dN v a l u e sa r er e a do fff r o mt h ed i a g r a m.

x i v )η Di sc a l c u l a t e d : η D ( c a l c u l a t e d ) =η H η R η O =( 1 t ) * η R η O / 1 w x v )T h ed i ff e r e n c eb e t we e nt h eη D ( c a l c u l a t e d )a n d η D ( a s s u me d )i sc a l c u l a t e da s : ε =|D ( c a l c u l a t e d) ηD ( a s s u me d) | i t e r a t ei fr e q u i r e d i fεv a l u e> ε t h r e s h o l d ,g ob a c kt os t e p( x )a n da s s u me η D ( a s s u me d ) =η D ( c a l c u l a t e d ) i fεv a l u e≤ ε t h r e s h o l d ,η D ( c a l c u l a t e d )i sc o n v e r g e d a n dη Di st h el a t e s tc a l c u l a t e dη D ( c a l c u l a t e d )

LA OLA |AUGUST 2017

x v i )Ba s e dupont hel a t e s tv a l ueofηDbr e a kpowe ri nt r i a lc ondi t i on PB( T RI AL )i s c a l c ul a t e da s : PB( T RI AL ) =PE ( T RI AL ) / DDDS =PD/ DS x v i i )I ns t a l l e dMa x i mum C ont i nuousP owe ri st a k e na s =PB( T RI AL )/ 0.

85 x v i i i )PD= PBηS 6 x i x )PB/ DBi sr e a doffa tt hec a l c ul a t e d( Bp ,δB)f r om t heBpδ di a gr a ma ndt he me a nf a c epi t c hi sc a l c ul a t e d.

LA OLA |AUGUST 2017

DI NALACHARY

DIGANTA GHOSH

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