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BRAYTON CYCLE:THE IDEAL CYCLE

FOR GAS-TURBINE ENGINES

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● The Brayton cycle wa !"rt #ro#oe$ %y Geor&e Brayton !or 'e "n therec"#-

rocat"n& o"l-%'rn"n& en&"ne that he $e(elo#e$ aro'n$ )*+,

● To$ay. "t " 'e$ !or &a t'r%"ne only where %oth the co/#re"on an$e0#an"on #rocee ta1e #lace "n rotat"n& /ach"nery

● Ga t'r%"ne ''ally o#erate on an o#en cycle. a hown "n F"& 2342Freh a"r at a/%"ent con$"t"on " $rawn "nto the co/#reor. where "tte/#erat're an$ #re're are ra"e$ The h"&h-#re're a"r #rocee$ "ntothe co/%'t"on cha/%er. where the !'el " %'rne$at contant #re're

● The re'lt"n& h"&h-te/#erat're &ae then enter the t'r%"ne. where they

e0#an$ to the at/o#her"c #re're wh"le #ro$'c"n& #ower The e0ha't&ae lea("n& the t'r%"ne are thrown o't 5not rec"rc'late$6. ca'"n& thecycle to %e cla"!"e$ a an o#en cycle

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O#en an$ Cloe$ Syte/

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Cycle

● Ientro#"c co/#re"on 5"n a co/#reor6

● Contant-#re're heat a$$"t"on

● Ientro#"c e0#an"on 5"n a t'r%"ne6

● Contant-#re're heat re7ect"on

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De(elo#/ent o! Ga T'r%"ne

● The &a t'r%"ne ha e0#er"ence$ #heno/enal #ro&re an$ &rowth"nce "t !"rt 'cce!'l $e(elo#/ent "n the )28,

● The early &a t'r%"ne %'"lt "n the )29, an$ e(en )2, ha$"/#le-cycle e!!"c"enc"e o! a%o't )+ #ercent %eca'e o! the lowco/#reor an$ t'r%"ne e!!"c"enc"e an$ low t'r%"ne "nlette/#erat're $'e to /etall'r&"cal l"/"tat"on o! thoe t"/e

● Ga t'r%"ne !o'n$ only l"/"te$ 'e $e#"te the"r (erat"l"ty an$the"r a%"l"ty to %'rn a (ar"ety o! !'el

● The e!!ort to "/#ro(e the cycle e!!"c"ency concentrate$ "n three

area: Increa"n& the t'r%"ne "nlet 5or !"r"n&6 te/#erat're.Increa"n& the e!!"c"enc"e o! t'r%o/ach"nery co/#onent. A$$"n&/o$"!"cat"on to the %a"c cycle

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Increa"n& the t'r%"ne "nlet 5or !"r"n&6te/#erat're

● The t'r%"ne "nlet te/#erat're ha(e "ncreae$ tea$"ly !ro/ a%o't 9,;C 5),,,;F6 "n

the )29, to )94;C 54a"nta"n"n& h"&h t'r%"ne "nlet te/#erat're w"th an a"r-cool"n& techn"='e re='"re theco/%'t"on te/#erat're to %e h"&her to co/#enate !or the cool"n& e!!ect o! thecool"n& a"r Howe(er. h"&her co/%'t"on te/#erat're "ncreae the a/o'nt o!n"tro&en o0"$e 5NO 0 6. wh"ch are re#on"%le !or the !or/at"on o! o?one at &ro'n$le(el an$ /o&

● U"n& tea/ a the coolant allowe$ an "ncreae "n the t'r%"ne "nlet te/#erat're %y4,,;F w"tho't an "ncreae "n the co/%'t"on te/#erat're Stea/ " alo a /'ch/ore e!!ect"(eheat tran!er /e$"'/ than a"r

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Increa"n& the e!!"c"enc"e o!t'r%o/ach"nery co/#onent

● The #er!or/ance o! early t'r%"ne '!!ere$ &reatly!ro/ the "ne!!"c"enc"e o! t'r%"ne an$co/#reor Howe(er. the a$(ent o! co/#'teran$ a$(ance$ techn"='e !or co/#'ter-a"$e$$e"&n /a$e "t #o"%le to $e"&n theeco/#onent aero$yna/"cally w"th /"n"/al loe

● The "ncreae$ e!!"c"enc"e o! the t'r%"ne an$

co/#reor re'lte$ "n a "&n"!"cant "ncreae "nthe cycle e!!"c"ency

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Contoh oal

A &a-t'r%"ne #ower #lant o#erat"n& on an "$ealBrayton cycle ha a #re're rat"o o! * The&a te/#erat're " 8,, @ at the co/#reor

"nlet an$ )8,, @ at the t'r%"ne "nlet Ut"l"?"n& thea"r-tan$ar$ a'/#t"on. $eter/"ne 5a6 the&a te/#erat're at the e0"t o! the co/#reoran$ the t'r%"ne. 5%6 the %ac1 wor1 rat"o. an$ 5c6

the ther/al e!!"c"ency

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SOAL

A "/#le "$eal Brayton cycle w"th a"r a the wor1"n& !l'"$ ha a #re're rat"o o! ), The a"renter the co/#reor at 4, R an$ the t'r%"ne

at 4,,, R Acco'nt"n& !or the (ar"at"on o!#ec"!"c heat w"th te/#erat're. $eter/"ne 5a6the a"r te/#erat're at the co/#reor e0"t. 5%6the %ac1 wor1 rat"o. an$ 5c6 the ther/al

e!!"c"ency

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IDEAL ET-ROULSION CYCLES

● Ga-t'r%"ne en&"ne are w"$ely 'e$ to #ower a"rcra!t %eca'e they are l"&ht an$ co/#actan$ ha(e a h"&h #ower-to-we"&ht rat"o

● A"rcra!t &a t'r%"ne o#erate on an o#en cycle calle$ a 7et-#ro#'l"on cycle

● The "$eal 7et-#ro#'l"on cycle $"!!er !ro/ the "/#le "$eal Brayton cycle "n that the

&ae are not e0#an$e$ to the a/%"ent #re're "n the t'r%"ne

●

Intea$. there are e0#an$e$ to a #re're 'ch that the #ower #ro$'ce$ %y the t'r%"ne " 7't '!!"c"ent to $r"(e the co/#reor an$ the a'0"l"ary e='"#/ent. 'ch a a /all&enerator an$ hy$ra'l"c #'/#

● That ". the net wor1 o't#'t o! a 7et-#ro#'l"on cycle " ?ero The &ae that e0"t the t'r%"neat a relat"(ely h"&h #re're are '%e='ently accelerate$ "n a no??le to #ro("$e the thr't to

#ro#el the a"rcra!t 5F"& 239+6

●

Alo. a"rcra!t &a t'r%"ne o#erate at h"&her #re're rat"o 5ty#"cally %etween ), an$ 46.an$ the !l'"$ #ae thro'&h a $"!!'er !"rt. where "t " $ecelerate$ an$ "t #re're ""ncreae$ %e!ore "t enter the co/#reor