104085614 JNTU Previous Paper Questions Thermodynamics

8/13/2019 104085614 JNTU Previous Paper Questions Thermodynamics

1/61

Code No: 07A3EC08 R07 Set No. 2

II B.Tech I Semester Examinations,A! 20""T#ER$%!NAICS

Common to echanica& En'ineerin', Aerona(tica& En'ineerin', A(tomo)i&e

En'ineerin'

Time: 3 ho(rs ax ar*s: 80Ans+er an -IE /(estions

A&& /(estions carr e(a& mar*s

". 1a hat are the ad4anta'es associated +ith the diese& cc&e as com5ared to theotto cc&e6

1) A 'as en'ine +or*in' on $tto cc&e has a c&inder o diameter 220mm and

stro*e 300 mm. The c&earance 4o&(me is "800 cc. -ind the airstandard

eicienc. Ass(me C5 9".00 *;?@"0

2. 1a Ex5&ain +ith a neat s*etch T dia'ram. 1nit

1) 2 *' o steam ex5ands adia)atica&& rom 20 )ar, 3000C to 0.D )ar in a

steam

t(r)ine s(ch that the steam is dr and sat(rated at the end o

ex5ansion.Ca&c(&ate

i. the +or* done ) steam, and

ii. +or* &ost d(e to irre4ersi)i&it. >8@8

3. 1a hat is an e(ation o state6

1) Air at "?0C and ".02 )ar occ(5ies a 4o&(me o 0.03 m3. The air is

heatedat constant 4o&(me (nti& the 5ress(re is .3 )ar and then coo&ed at

constant5ress(re )ac* to the ori'ina& tem5erat(re. ca&c(&ate

i. The net heat &o+ to or rom the air and

ii. The net entro5 chan'e. >?@"0

. 1a Ex5&ain +ith neat s*etch the +or*in' o 4a5o(r com5ression reri'eration cc&e

1) %escri)e a )inar 4a5o(r cc&e +ith the he&5 o schematic dia'ram o the 5&antand TS dia'ram o the cc&e. >8@8

D. An en'ine +or*in' on Carnot cc&e a)sor)s /" (nits o heat rom a so(rceat T"

and reects /2 (nits o heat to a sin* at T2. Te tem5erat(re o the +or*in'&(id is" and 2, +here " F T" and 2 G T2,

I " 9 T"=/" and 2 9 T2@*/2


2/61

+here * is constant, then sho+ that eicienc o the en'ine is 'i4en ):

9 " H T2 >"?T"H2*/". 1nit 3

?. 1a %eri4e stead &o+ ener' e(ation and sim5&i the e(ation +hen a55&ied to

i. as t(r)ine

ii. Com5ressors 1nit 2

"


3/61

or* done ) a s()stance in a re4ersi)&e non&o+ manner is in accordance


1) A &(id sstem (nder 'oes a non&o+ riction&ess 5rocess o&&o+in' the5ress(re

4o&(me re&ation as 59D


4/61

2


5/61

or* do1e ) a s()stance in a re4ersi)&e non&o+ manner is in accordance

Code No: 07A3EC08 R07 Set No.



En'ineerin'Time: 3 ho(rs ax ar*s: 80

Ans+er an -IE /(estionsA&& /(estions carr e(a& mar*s

". 1a %escri)e the method o deh(midiication ) coo&in' and sho+ it on 5schrometric chart. %eri4e ener' e(ation or this 5rocess.

1) A therma&& ins(&ated 4esse& contains 3 *' mo&e o #2 and ".D *' mo&e o N2each at " )ar 270C initia&& the are se5arated ) a 5artition +a&&. %eterminethe chan'e in entro5 +hen the 5artition +a&& is remo4ed and the t+o 'asesmixes. >8@8

2. 1a Ex5&ain +ith neat s*etch the +or*in' o 4a5o(r com5ression reri'eration cc&e


3. 1a hat are the dierent t5es o thermodnamic sstems6 Ex5&ain +ith exam5&es. nit I

1)

+ith 9 "D0 m3, +here 5 is in )ar. E4a&(ate the +or* done on or ) the

5

sstem as 5ress(re increases rom "0 to "00 )ar. Indicate +hether it is acom5ression or ex5ansion 5rocess. >8@8

. 1a hat is an e(ation o state6

1) Air at "?0C and ".02 )ar occ(5ies a 4o&(me o 0.03 m3. The air is

heatedat constant 4o&(me (nti& the 5ress(re is .3 )ar and then coo&ed at

constant5ress(re )ac* to the ori'ina& tem5erat(re. ca&c(&ate



D. 1a %eri4e stead &o+ ener' e(ation and sim5&i the e(ation +hen a55&ied to

i. as t(r)ine

ii. Com5ressors nit II




6/61

ii. chan'e in entha&5. >8@8

3


7/61

Code No: 07A3EC08 R07 Set No.

?. An en'ine +or*in' on Carnot cc&e a)sor)s /" (nits o heat rom a so(rceat T"

and reects /2 (nits o heat to a sin* at T2. Te tem5erat(re o the +or*in'&(id is" and 2, +here " F T" and 2 G T2,

I " 9 T"=/" and 2 9 T2@*/2 NIT III+here * is constant, then sho+ that eicienc o the en'ine is 'i4en ):

9 " H T2 >"?T"H2*/". nit 1III

7. 1a hat are the ad4anta'es associated +ith the diese& cc&e as com5ared to the

otto cc&e61) A 'as en'ine +or*in' on $tto cc&e has a c&inder o diameter 220 mm and

stro*e 300 mm. The c&earance 4o&(me is "800 cc. -ind the airstandardeicienc. Ass(me C5 9".00 *;?@"0

8. 1a Ex5&ain +ith a neat s*etch T dia'ram. NIT I

1) 2 *' o steam ex5ands adia)atica&& rom 20 )ar, 3000C to 0.D )ar in asteam

t(r)ine s(ch that the steam is dr and sat(rated at the end oex5ansion.Ca&c(&ate




8/61

:


9/61


Code No: 07A3EC08 R07 Set No. "



En'ineerin'


A&& /(estions carr e(a&mar*s

". 1a %escri)e the method o deh(midiication ) coo&in' and sho+ it on 5schrometric chart. %eri4e ener' e(ation or this 5rocess.

1) A therma&& ins(&ated 4esse& contains 3 *' mo&e o #2 and ".D *' mo&eo N2

each at " )ar 270C initia&& the are se5arated ) a 5artition +a&&.%etermine

the chan'e in entro5 +hen the 5artition +a&& is remo4ed and the t+o'ases

mixes. >8@8

2. An en'ine +or*in' on Carnot cc&e a)sor)s /" (nits o heat rom a so(rceat T"

and reects /2 (nits o heat to a sin* at T2. Te tem5erat(re o the +or*in'&(id is" and 2, +here " F T" and 2 G T2,I " 9 T"=/" and 2 9 T2@*/2+here * is constant, then sho+ that eicienc o the en'ine is 'i4en ):

9 " H T2 >"?T"H2*/".


otto cc&e6

1) A 'as en'ine +or*in' on $tto cc&e has a c&inder o diameter 220 mm andstro*e 300 mm. The c&earance 4o&(me is "800 cc. -ind the airstandardeicienc. Ass(me C5 9".00 *;?@"0

. 1a Ex5&ain +ith neat s*etch the +or*in' o 4a5o(r com5ression reri'eration cc&e


D. 1a hat are the dierent t5es o thermodnamic sstems6 Ex5&ain +ith exam

5&es.1)

+ith 9 "D0 m3, +here 5 is in )ar. E4a&(ate the +or* done on or ) the

5



10/61

?. 1a hat is an e(ation o state6

1) Air at "?0C and ".02 )ar occ(5ies a 4o&(me o 0.03 m3. The air isheated

at constant 4o&(me (nti& the 5ress(re is .3 )ar and then coo&ed atconstant

5ress(re )ac* to the ori'ina& tem5erat(re. ca&c(&ate


D


11/61

Code No: 07A3EC08 R07 Set No. "


7. 1a %eri4e stead &o+ ener' e(ation and sim5&i the e(ation +hen a55&ied to

i. as t(r)ine

ii. Com5ressors




12/61

?


13/61





En'ineerin'



". 1a hat are the dierent t5es o thermodnamic sstems6 Ex5&ain +ith exam5&es.

1)

+ith9

"D05

m3, +here 5 is in )ar. E4a&(ate the +or* done on or ) the



otto cc&e61) A 'as en'ine +or*in' on $tto cc&e has a c&inder o diameter 220 mm and

stro*e 300 mm. The c&earance 4o&(me is "800 cc. -ind the airstandardeicienc. Ass(me C5 9".00 *;?@"0

3. 1a hat is an e(ation o state6

1) Air at "?0C and ".02 )ar occ(5ies a 4o&(me o 0.03 m3. The air isheated

at constant 4o&(me (nti& the 5ress(re is .3 )ar and then coo&ed atconstant

5ress(re )ac* to the ori'ina& tem5erat(re. ca&c(&ate



. 1a Ex5&ain +ith a neat s*etch T dia'ram.

1) 2 *' o steam ex5ands adia)atica&& rom 20 )ar, 3000C to 0.D )ar in asteam

t(r)ine s(ch that the steam is dr and sat(rated at the end o

ex5ansion.Ca&c(&ate



D. 1a %eri4e stead &o+ ener' e(ation and sim5&i the e(ation +hen a55&ied to


14/61

i. as t(r)ine

ii. Com5ressors




15/61

Code No: 07A3EC08

ii. chan'e in entha&5.

R07 Set No. 3

>8@8

?. 1a Ex5&ain +ith neat s*etch the +or*in' o 4a5o(r com5ression reri'eration cc&e

1) %escri)e a )inar 4a5o(r cc&e +ith the he&5 o schematic dia'ram o the 5&ant

and TS dia'ram o the cc&e. >8@8

7. An en'ine +or*in' on Carnot cc&e a)sor)s /" (nits o heat rom a so(rceat T"

and reects /2 (nits o heat to a sin* at T2. Te tem5erat(re o the +or*in'&(id is

" and 2, +here " F T" and 2 G T2, I " 9 T"=/" and 2 9 T2@*/2+here * is constant, then sho+ that eicienc o the en'ine is 'i4en ):9 " H

T 2

T"H2*/".>"?A

8. 1a %escri)e the method o deh(midiication ) coo&in' and sho+ it on 5schrometric chart. %eri4e ener' e(ation or this 5rocess.

1) A therma&& ins(&ated 4esse& contains 3 *' mo&e o #2 and ".D *' mo&eo N2

each at " )ar 270C initia&& the are se5arated ) a 5artition +a&&.

%eterminethe chan'e in entro5 +hen the 5artition +a&& is remo4ed and the t+o

'asesmixes. >8@8


16/61

8

Code No: R0D2"030 R0D Set No. 2

II B.Tech I Semester Examinations,No4em)er 20"0

T#ER$%!NAICS

Common to echanica& En'ineerin', A(tomo)i&e En'ineerin'Time: 3 ho(rs ax ar*s: 80

Ans+er an -IE /(estions

A&& /(estions carr e(a&

mar*s

". 1a Ex5&ain the im5ortant com5onents o a sim5&e 4a5o(r com5ression reri'era

tion sstem. A&so disc(ss the (nctions o each com5onent.

1) %isc(ss the eect o s() coo&in' on C.$..o the 4a5o(r com5ression reri'er

ation cc&e. o(&d o( deri4e &ar'e s() coo&in' and +h6 >8@8

2. 1a %ed(ce the re&ation shi5 )et+een a)so&(te tem5erat(re and 5ress(re in an5o&tro5ic 5rocess.

1) 0.3m3 o air at 5ress(re 8 )ars ex5ands to ".Dm3 . The ina& 5ress(reis ".3

)ar. Ass(min' the ex5ansion to )e 5o&tro5ic, ca&c(&ate the heats(55&ied and

chan'e o interna& ener'. Ta*e 4.1= >7@J

3. A cc&e consists o three 5rocesses. The irst is a constant 5ress(recom5ression at

200 =a rom an initia& 4o&(me o 0.7 m3 to a ina& 4o&(me o 0.2 m3. Thesecond

5rocess ta*es 5&ace at constant 4o&(me +ith the 5ress(re increasin' to ?00=a.

The third 5rocess to the )e'innin' o the irst 5rocess. S*etch the cc&e on4

coordinates, and ca&c(&ate the net +or* transer. >"?

:. 1a a*e an ener' ana&sis o the steam noKK&e and heat exchan'er.

1) Reri'erant 4a5o(r enters the condenser o a reri'eration 5&ant +ithentha&5

223.7D =;


17/61

D. 1a List o(t dierent co&orimeters (sed to ind the (a&it o +et steam, Ex5&ainan one o them.

1) In a steam en'ine the steam at the )e'innin' o the ex5ansion5rocess is at

7 )ar, drness raction 0.J8 and ex5ansion o&&o+s the &o+ 4"." 9constant

,do+n to a 5ress(re o 0.3 )ar, ca&c(&ate The +or* done d(rin'ex5ansion 5er

*' o steam. >7@J

?. 1a State the =e&4in&an* and C&a(si(s statements o the second &a+ o thermodnamics and esta)&ish e(i4a&ence )et+een them.

1) %etermine the 5o+er re(ired to r(n a reri'erator that transers 2000

=;"0@?

7. An en'ine +ith 200mm c&inder diameter and 300mm stro*e +or*s ondiese& cc&e.

The initia& 5ress(re and tem5erat(re o air (sed are " )ar and 270

C. Thec(tois 8M o the stro*e. %etermine:

"


18/61


1a Tem5erat(res and 5ress(res at a&& sa&ient 5oints

1) Air standard eicienc. >"?

8. 1a rite shoot notes on

i. B 5ass actor

ii. %e'ree o sat(ration

iii. Adia)atic mixin'

i4. #(midiication

1) 200m3 o air 5er min(te at "D0C %BT and 7D -ind

i. R. it o heated air

ii. et )(&) tem5erat(re o heated air

iii. #eat added to air 5er min(te >8@8


19/61

2


20/61

Code No: R0D2"030 R0D Set No.

II B.Tech I Semester Examinations,No4em)er 20"0T#ER$%!NAICS

Common to echanica& En'ineerin', A(tomo)i&e En'ineerin'



mar*s

". An en'ine +ith 200mm c&inder diameter and 300mm stro*e +or*s ondiese& cc&e.

The initia& 5ress(re and tem5erat(re o air (sed are " )ar and 270C. Thec(to

is 8M o the stro*e. %etermine:



2. 1a Ex5&ain the im5ortant com5onents o a sim5&e 4a5o(r com5ression reri'eration sstem. A&so disc(ss the (nctions o each com5onent.

1) %isc(ss the eect o s() coo&in' on C.$..o the 4a5o(r com5ression reri'eration cc&e. o(&d o( deri4e &ar'e s() coo&in' and +h6 >8@8

3. 1a List o(t dierent co&orimeters (sed to ind the (a&it o +et steam, Ex5&ainan one o them. NIT I



,do+n to a 5ress(re o 0.3 )ar, ca&c(&ate The +or* done d(rin'

ex5ansion 5er*' o steam. >7@J

. 1a a*e an ener' ana&sis o the steam noKK&e and heat exchan'er.NIT II

1) Reri'erant 4a5o(r enters the condenser o a reri'eration 5&ant +ith entha&5223.7D =;7@J


21/61

?. A cc&e consists o three 5rocesses. The irst is a constant 5ress(re

com5ression at200 =a rom an initia& 4o&(me o 0.7 m3 to a ina& 4o&(me o 0.2 m3. The

second5rocess ta*es 5&ace at constant 4o&(me +ith the 5ress(re increasin' to ?00

=a.The third 5rocess to the )e'innin' o the irst 5rocess. S*etch the cc&e on

4coordinates, and ca&c(&ate the net +or* transer. >"?


3


22/61

Code No: R0D2"030

i. B 5ass actor

ii. %e'ree osat(ration


i4. #(midiication

R0D Set No.





8. 1a State the =e&4in&an* and C&a(si(s statements o the second &a+ o thermo

dnamics and esta)&ish e(i4a&ence )et+een them.NIT III

1) %etermine the 5o+er re(ired to r(n a reri'erator that transers 2000

=;"0@?


23/61

:


24/61

Code No: R0D2"030 R0D Set No. "





". 1a %ed(ce the re&ation shi5 )et+een a)so&(te tem5erat(re and 5ress(re in an5o&tro5ic 5rocess.

1) 0.3m3 o air at 5ress(re 8 )ars ex5ands to ".Dm3 . The ina& 5ress(re

is ".3

)ar. Ass(min' the ex5ansion to )e 5o&tro5ic, ca&c(&ate the heat

s(55&ied andchan'e o interna& ener'. Ta*e 9 ". >7@J

2. 1a Ex5&ain the im5ortant com5onents o a sim5&e 4a5o(r com5ression reri'eration sstem. A&so disc(ss the (nctions o each com5onent.

1) %isc(ss the eect o s() coo&in' on C.$..o the 4a5o(r com5ression reri'er

ation cc&e. o(&d o( deri4e &ar'e s() coo&in' and +h6 >8@83. A cc&e consists o three 5rocesses. The irst is a constant 5ress(re

com5ression at200 =a rom an initia& 4o&(me o 0.7 m3 to a ina& 4o&(me o 0.2 m3. The

second5rocess ta*es 5&ace at constant 4o&(me +ith the 5ress(re increasin' to ?00

=a.The third 5rocess to the )e'innin' o the irst 5rocess. S*etch the cc&e on

4coordinates, and ca&c(&ate the net +or* transer. >"?

:. 1a a*e an ener' ana&sis o the steam noKK&e and heat exchan'er.

1) Reri'erant 4a5o(r enters the condenser o a reri'eration 5&ant +ithentha&5

223.7D =;


25/61

?. 1a rite shoot notes on

i. B 5ass actor

ii. %e'ree o sat(ration


i4. #(midiication



D


26/61

Code No: R0D2"030 R0D Set No. "



7. 1a List o(t dierent co&orimeters (sed to ind the (a&it o +et steam, Ex5&ainan one o them.



,do+n to a 5ress(re o 0.3 )ar, ca&c(&ate The +or* done d(rin'

ex5ansion 5er*' o steam. >7@J

8. An en'ine +ith 200mm c&inder diameter and 300mm stro*e +or*s ondiese& cc&e.

The initia& 5ress(re and tem5erat(re o air (sed are " )ar and 270C. Thec(to

is 8M o the stro*e. %etermine:




27/61

?


28/61






mar*s

". 1a State the =e&4in&an* and C&a(si(s statements o the second &a+ o thermodnamics and esta)&ish e(i4a&ence )et+een them.

1) %etermine the 5o+er re(ired to r(n a reri'erator that transers 2000=;"0@?

2. An en'ine +ith 200mm c&inder diameter and 300mm stro*e +or*s on diese& cc&e.The initia& 5ress(re and tem5erat(re o air (sed are " )ar and 270C. The c(tois 8M o the stro*e. %etermine:



3. 1a List o(t dierent co&orimeters (sed to ind the (a&it o +et steam, Ex5&ainan one o them.



,do+n to a 5ress(re o 0.3 )ar, ca&c(&ate The +or* done d(rin'ex5ansion 5er

*' o steam. >7@J

. 1a %ed(ce the re&ation shi5 )et+een a)so&(te tem5erat(re and 5ress(re in an5o&tro5ic 5rocess.

1) 0.3m3 o air at 5ress(re 8 )ars ex5ands to ".Dm3 . The ina& 5ress(re is ".3)ar. Ass(min' the ex5ansion to )e 5o&tro5ic, ca&c(&ate the heat s(55&ied andchan'e o interna& ener'. Ta*e 9 ". >7@J

D. 1a a*e an ener' ana&sis o the steam noKK&e and heat exchan'er.

1) Reri'erant 4a5o(r enters the condenser o a reri'eration 5&ant +ith entha&5223.7D =;


29/61

tion sstem. A&so disc(ss the (nctions o each com5onent.

1) %isc(ss the eect o s() coo&in' on C.$..o the 4a5o(r com5ression reri'eration cc&e. o(&d o( deri4e &ar'e s() coo&in' and +h6 >8@8


7


30/61

Code No: R0D2"030

i. B 5ass actor

ii. %e'ree osat(ration


i4. #(midiication

R0D Set No. 3





8. A cc&e consists o three 5rocesses. The irst is a constant 5ress(recom5ression at

200 =a rom an initia& 4o&(me o 0.7 m3 to a ina& 4o&(me o 0.2 m3. Thesecond

5rocess ta*es 5&ace at constant 4o&(me +ith the 5ress(re increasin' to ?00=a.

The third 5rocess to the )e'innin' o the irst 5rocess. S*etch the cc&e on4

coordinates, and ca&c(&ate the net +or* transer. >"?


31/61

8

Code No: 3""8@8

2. 1a Ener' is a 5oint (nction. Ex5&ain and 5ro4e. 1nit II

1) ro4e that heat and +or* are 5ath (nctions. >8@8

3. 1a hat are adia)atic and diathermic +a&&s6 1nit II

1) The &o+ ener' o 0."2 m3


32/61

atmos5heric 5ress(re is " )ar, determine 5er *' o dr air

1a the amo(nt o heat re(ired d(rin' the 5rocess, and

1) the amo(nt o +ater e4a5orated in the s5ra +ater (nit res5ecti4e&.Com5(te

a&so the h(midiin' eicienc o the s5ra +ater (nit. &ot the 5rocesson

the 5schrometric chart. >"?

?. 1a Ex5&ain the si'niicance o ander +a&&s e(ation and its &imitations

1) A tan* o 4o&(me ".3 m3 is i&&ed +ith ar'on at ? )ar and 2?0oC. Ithe 'as

+ithin the tan* chan'es its state isentro5ica&& +hen it &o+s romthe tan*

(nti& the 5ress(re dro5s to the atmos5heric 5ress(re o " )ar,determine the

mass o the 'as that has &et the tan* d(rin' the 5rocess. >?@"0

"


33/61

Code No: 3""


34/61

2


35/61

Code No: 3"""?

2. 1a %emonstrate, (sin' the second &a+, that ree ex5ansion is irre4ersi)&e.1) A domestic ood reeKer maintains a tem5erat(re o "D0 C +itham)ient tem

5erat(re o 300C. I heat &ea*s into he reeKer at the contin(o(s rateo ".7D

*;8@8

3. 1a hat is an air standard cc&e6 h are s(ch cc&es concei4ed6

1) -ind the air standard eiciencies or $tto cc&es +ith a com5ression ratio o ?(sin' idea& 'ases ha4in' s5eciic heat ratios ".3D, ".3 and ".?2. hat are thead4anta'es and disad4anta'es o (sin' he&i(m as the +or*in' &(id6 >?@"0

. 1a Ex5&ain microsco5ic and macrosco5ic a55roach +ith exam5&es.

1) A 5(m5 orces ".2m


36/61

the condensate )ein' drained o at "7.DoC. The res(&tin' sat(rated mixt(reis then

heated to 5rod(ce the re(ired conditions o DDM R# at 23oC. The tota&5ress(re

is constant at "0" *a. %etermine the mass o +ater s(55&ied to thes5ras to

5ro4ide "2 m3"?A

?. A ? ton idea& 4a5o(r com5ression reri'erator +or*s )et+een thecondensin' 5res

s(re o "2 )ar and e4a5oratin' 5ress(re o 3.3 )ar. The reri'erant is drsat(rated

4a5o(r )eore it enters the com5ressor. Sat(rated &i(id reri'erant entersinto the

ex5ansion 4a&4e rom the condenser. The a4era'e s5eciic heat o thes(5erheated

reri'erant 4a5o(r at constant 5ress(re is ".7 *;


37/61

Code No: 3"""?A

7. A ri'id 4esse& contains " =' o a mixt(re o sat(rated +ater and sat(ratedsteam

at a 5ress(re o 0."D 5a. hen the mixt(re is heated, the state 5assesthro('h

the critica& 5oint. %etermine the 4o&(me o the 4esse&, the mass o the&i(id and

4a5o(r in the 4esse& initia&&, the tem5erat(re o the mixt(re +hen the5ress(re has

risen to 35a, and the heat transer re(ired to 5rod(ce the ina& state.>"?

8. 1a Ex5&ain +hat is I6

1) Steam enters a steam t(r)ine +ith a 4o&ocit o "? m


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:


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52

Code No: 3""[email protected]+o containers 5 and +ith ri'id +a&&s contain t+o dierent monoatomic'ases

+ith masses m5 and m 'as constants R5 and R, and initia& tem5erat(resT5 and

T res5ecti4e&, are )ro('ht in contact +ith each other and a&&o+ed to exchan'e

ener' (nti& e(i&i)ri(m is achie4ed. %etermine:

1a the ina& tem5erat(re o the t+o 'ases and

1) the chan'e o entro5 d(e to this ener' exchan'e. >"?

. 1a Sho+ that the adia)atic mixin' o t+o &(ids is irre4ersi)&e. 1nit III

1) Sho+ that i t+o )odies o therma& ca5acities C"and C2 at tem5erat(res T"

and T2 are )ro('ht to the same tem5erat(re, T ) means o are4ersi)&e heat

en'ine, thenIn T9 C"&n T"@C2&n T2 >8@8

C"@C2

D. 1a hat are the ad4anta'es and disad4anta'es o air reri'eration sstems o4erthe other6

1) %etermine the tem5erat(re ratio 1T2 < T" 1+here T2 9 so(rcetem5erat(re

and T" 9 sin* tem5erat(re or a Carnot reri'erator +hose C$ is D.A&so

ca&c(&ate the reri'eration ca5acit o the machine in tons oreri'eration i the

5o+er cons(m5tion is 8 *. I the cc&e is (sed as heat 5(m5, ind the


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C$or heatin' cc&e and the (antit o heat 5(m5ed ass(min' same

tem5erat(re

ran'e. >?@"0

?. 1a Sho+ that the +or* done d(rin' a &o+ 5rocess is H 4d5 1nit II

5"

1) A certain mass o s(&5h(r dioxide 1S02 is contained in a 4esse& o0."D m3

ca5acit, at a 5ress(re and tem5erat(re o 2.2 )ar and 20oC

res5ecti4e&. A

D


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Code No: 3""?@"0

7. 1a hat is 5rinci5&e o o5eration o an e&ectria& ca&orimeter6

1) A 4esse& o 0.0 m3 contains a mixt(re o sat(rated +ater and sat(ratedsteam

at a tem5erat(re o 2D00C. The mass o the &i(id 5resent is J ='.-ind the

5ress(re, the mass, the s5eciic 4o&(me, the entha&5, the entro5 and

interna&ener' (sin' steam ta)&e on&. >?@"0

8. 1a Ex5&ain the +or* interaction )et+een a sstem and the s(rro(ndin's.

1) The 5istion o an oi& en'ine, o area 0.00D m2, mo4es do+n+ards 7Dmm,

dra+in' in 0.0028 m3 o resh air rom the atmos5here. The 5ress(rein the

c&inder is (niorm d(rin' the 5rocess at 80 *a, +hi&e the atmos5heric5res

s(re is "0".32D *a, the dierence )ein' d(e to the &o+ resistancein the

ind(ction 5i5e and the in&et 4a&4e. Estimate the dis5&acement +or*done )

the air ina&& in the c&inder. >?@"0


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?


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Code No: 3"""?

2. 1a %eine the s5eciic heats at constant 4o&(me and at constant 5ress(re.

1) ".D =' o &i(id ha4in' a constant s5eciic heat o 2.D =;?@"0

:.The (s(a& coo*in' 'as 1most& methane cc&inder is a)o(t 20 cm in

diameter and

"00 cm in hei'ht. It is char'ed to "".D a at room tem5erat(re o 2DoC.

1a Ass(min' the idea& 'as &a+, ind the mass o 'as i&&ed in the cc&inder.

1) Ex5&ain ho+ the act(a& cc&inder contains near& "D *' o 'as.

1c I the c&inder is to )e 5rotected a'ainst excessi4e 5ress(re )


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means o a(si)&e 5&(', at +hat tem5erat(re sho(&d the 5&(' me&t to &imit the

maxim(m

5ress(re to "D a6 >"?

D. 1a %isti'(ish )et+een o5en sstem and c&osed sstem. 1nit I

1) A 'as at a 5ress(re o "38 *N


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Code No: 3"""?

8. -or an air standard $tto cc&e +ith ixed inta*e and maxim(mtem5erat(res, T"

and T3, ind the com5ression ratio that renders the net +or* 5er cc&e amaxim(m.

%eri4e the ex5ression or cc&e eicienc at this com5ression ratio. I the air

inta*etem5erat(re, T", is 30D = and the maxim(m cc&e tem5erat(re, T3, is

"300 =,com5(te the com5ression ratio or maxim(m net +or*, maxim(m +or*

o(t5(t5er *' in a cc&e, and the corres5ondin' cc&e eicienc. -ind the

chan'es in+or* o(t5(t and cc&e eicienc +hen the com5ression ratio is increased

rom thiso5tim(m 4a&(e to 8. Ta*e C4 9 0.7"8 *;


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8

Code No: 07A3EC08 Set No. "

II B.Tech I Semester Re'(&ar Examinations, No4em)er 2008

T#ER$%!NAICS

1 Common to echanica& En'ineerin', Aerona(tica& En'ineerin' and

A(tomo)i&e En'ineerin'Time: 3 ho(rs ax ar*s: 80

Ans+er an -IE /(estions


". 1a Ex5&ain the contro& 4o&(me and its si'niicance. 1nit I

1) I a 'as o 4o&(me ?000 cm3 and at a 5ress(re o "00 *a, is com5ressed(asistatica&& to 529constant (nti& the 4o&(me )ecomes 2000 cm3. Ca&c(atethe ina& 5ress(re and the +or* transer. >?@"0

2. 1a Constant 5ress(re 'as thermometerex5&ain in detai&.1nit II

1)The readin's tA and tB o t+o ce&si(s thermometers A and B a'ree +e&&

at ice

5oint 100 C and steam 5oint 1"000. At other 5oints )et+een these

t+o, the

tem5erat(res are re&ated ) tA95@tB@rt2 B, here 5, and r are

constants.hen the t+o thermometers are immersed in a +e&& stirred oi& )ath,

+hi&e A reads D", B reads D0.

i. %etermine +hat A reads +hen B reads 30.

ii. %isc(ss the (estion o +hich thermometer is correct. >?@"0

3. 1a Ex5&ain the ca(ses o Irre4eris)i&it.1nit III

1) An in4ertor c&aims to ha4e de4e&o5ed an en'ine that ta*es in "0D ; at atem5erat(re o 00*, reets 2 ; at a tem5erat(re o 200 *, and de&i4ers"D =+h o mechanica& +or*. Listin' o(t a&& the reasons, s(''est o(r ad4icein4entin' mone to 5(t this en'ine in the mar*et. >8@8


47/61

. 1a Ex5&ain the si'niicance o Tri55&e 5oint in case o 5(re s()stance.

1) Ex5&ain in detai& the ormation o steam +ith the he&5 o T# dia'ram indicatin' the sa&ient 5oints. >8@8

D. An idea& 'as cc&e o three 5rocesses (ses Ar'on 1o&. +t.0 as a +or*in's()stance. rocess "2 is a re4ersi)&e adia)atic ex5ansion rom 0.0"D m3,?D0 *a, 270oC to 0.0?? m3. rocess 23 is a re4ersi)&e isotherma& 5rocess.

rocess 3" is a constant 5ress(re 5rocess in +hich heat transer is Kero.S*etch the cc&e in the 54 and Ts 5&anes, and ind

1a the +or* transer in 5rocess "2,1) the +or* transer in 5rocess 23, and

1c the net +or* o the cc&e. Ta*e 9 ".?7. >"?

" o 2


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Code No: 07A3EC08 Set No. "

?. A 4esse& is di4ided into three com5artments 1a, 1), and 1c ) t+o 5artitions. art1a contains $x'en and has a 4o&(me o 0."D m3, 1) has a 4o&(me o 0.2Dm3 andcontains Nitro'en, +hi&e 1c is 0.0D m3 and ho&ds Car)on diaoxide. A&& three5artsare at a 5ress(re o 2.D )ar and a tem5erat(re o "D0C. hen the5artitions areremo4ed and the 'ases mix, determine the chan'e o entro5 o eachconstit(ent,the ina& 5ress(re in the 4esse& and the 5artia& 5ress(re o each 'as. The

4esse& ma)e ta*en as )ein' com5&ete& iso&ated rom its s(rro(ndin's. >"?

7. 1a hat are cc&ic and noncc&ic heat en'ines6 i4e exam5&es.

1) State the o(r 5rocesses that constit(te the Ericsson cc&e. Sho+ thatthe re

'enerati4e Ericsson cc&e has the same eicienc as the Carnot cc&e.ention

the merits and demerits o the Stir&in' and Ericsson cc&es. >?@"0

8. -or an idea& 4a5orcom5ression reri'eratin' sstem (sin' R"3a and dr

com5ression, the reri'erated re'ion is to )e *e5t at 3oC, and the am)ient air to

+hichheat is reected is at 30oC. The rate o heat remo4a& rom the reri'erated

re'ionis 200 *;"?A


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2 o 2


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Code No: 07A3EC08 Set No. 2

II B.Tech I Semester Re'(&ar Examinations, No4em)er 2008T#ER$%!NAICS

1 Common to echanica& En'ineerin', Aerona(tica& En'ineerin' andA(tomo)i&e En'ineerin'



". 1a Ener' is a 5oint (nction. Ex5&ain and 5ro4e. 1nit I

1) ro4e that heat and +or* are 5ath (nctions. >8@8

2. 1a State the irst &a+ o thermodnamics and 5ro4e that or non &o+ 5rocess it&eads to /9@ . 1nit II

1) %eine I and the re&e4ance o it. >8@8

3. 1a Sho+ that the C$ o heat 5(m5 is 'reater than the C$ o a reri'erator) (nit. 1nit III

1) ro4e that the eicienc o a re4ersi)&e en'ine o5eratin' )et+een t+o 'i4enconstant tem5erat(res is the maxim(m. >8@8

. 1a h cannot a thrott&in' ca&orimeter meas(re the (a&it i the steam is 4er+et6 1nit I

1) -ind the entha&5, entro5 and 4o&(me o steam at ". 5a, 3800 C. sin'steam ta)&es on&. >?@"0

D. 1a rite do+n the 4an der aa&s e(ation o state. #o+ does it dier rom theidea& 'as e(ation o state6

1) A 'as occ(5ies 0.03 m3 at ?00 *a and 8Do

C. It is ex5anded in thenon&o+5rocess accordin' to the &a+ 5".2 9 constant to a 5ress(re o ?0 *a

ater+hich it is heated at constant 5ress(re )ac* to its ori'ina& tem5erat(re.

S*etchthe 5rocess on the 54 and Ts dia'rams, and ca&c(&ate or the +ho&e

5rocessthe +or* done, the heat transerred. Ta*e C5 9 ".07 and C4 9 0.77D

*;?@"0

?. A 'aseo(s mixt(re contains 23 M ) 4o&(me o Nitro'en, DM ) 4o&(meo #

dro'en, and 32M ) 4o&(me o Car)ondioxide. Ca&c(&ate the o&ec(&ar+ei'ht

o the mixt(re, the characteristic 'as constant R or the mixt(re and the4a&(e o


51/61

the re4ersi)&e adia)atic index . 1At "0 oC, the c5 4a&(es o Nitro'en,#dro'en,

and Car)on dioxide are ".0, "3.JD, and 0.8D *;


52/61


1) An en'ine e(i55ed +ith a c&inder ha4in' a )ore o "2 cm and a stro*e o 0cm o5erates on an $tto cc&e. I the c&earance 4o&(me is "?00 cm3, com5(tethe air standard eicienc. >8@8

8. 1a %eri4e the ex5ression or C$ o Be&& Co&eman cc&e +hen the com5ressionand ex5ansion are isentro5ic

1) An air reri'eratin' 5&ant o5erates )et+een ".? )ar and 8 )ar. Theca5acit

o the 5&ant is D.D ton. The tem5erat(re o the air enterin' thecom5ressor

and into an air en'ine is o

C and 2Jo

C res5ecti4e&. The com5ressionand

ex5ansion 5rocesses are 5o&tro5ic +ith ex5onent n 9 ".3D.%etermine the

C$ and the net 5o+er in5(t or the 5&ant. >8@8


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2 o 2


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". 1a hat do o( (nderstand ) state (nction and 5ath (nction6 1nit I

1) ro4e that +or* is a 5ath (nction and 5ro5erties are 5oint (nctions. >?@"0

2. 1a h sho(&d s5eciic heat not )e deined in terms o heat transer6 1nit II

1) %(rin' one cc&e, the +or*in' &(id in an en'ine en'a'es in t+o +or* interactions: "D =; to the &(id and =; rom the &(id, and three heat interations,t+o o +hich are 7D *; o the &(id and 0 =; rom the &(id. E4a&(te thema'nit(de and direction o the third heat transer. >?@"0

3. 1a Ex5&ain the conce5t o heat 5(m5 ea&)orate&. 1nit III

1) A heat en'ine 5erorms man cc&es d(rin' +hich it de4e&o5s 2" *; +or* andrecei4es 8D *; heat rom the so(rce. E4a&(ate the therma& eicienc and theheat reected ) the en'ine. >8@8

. 1a %eine sensi)&e heat and dr steam. 1nit I

1) A s5herica& she&& o diameter D0 cm contains steam at a 5ress(re o 0 )ar and0.8D drness raction. Ca&c(&ate the mass o +ater and steam. >?@"0

D. 1a Ex5&ain the si'niicance o ander +a&&s e(ation and its &imitations

1) A tan* o 4o&(me ".3 m3 is i&&ed +ith ar'on at ? )ar and 2?0oC. Ithe 'as

+ithin the tan* chan'es its state isentro5ica&& +hen it &o+s romthe tan*

(nti& the 5ress(re dro5s to the atmos5heric 5ress(re o " )ar,determine the

mass o the 'as that has &et the tan* d(rin' the 5rocess. >?@"0

?. A sstem consistin' o three tan*s, a&& interconnected ) 5i5es and 4a&4es,contains

Nitro'en, $x'en, and Ar'on. $ne tan* contains D *' o Nitro'en at ?D0*a,

23o

CO another 3.D *' o Ar'on at D0 *a, 8o

CO and the third 7 *' o$x'en at300 *a, 80oC. Ater the 4a&4es are o5ened and the sstem is a&&o+ed to

come toe(i&i)ri(m, com5(te or the mixt(re

1a the tem5erat(re


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1) the a55arent mo&ar mass

1c the constant5ress(re s5eciic heat

1d the 'as constant

1e the 5ress(re and

" o 2


56/61

Code No: 07A3EC08

1 the 5artia& 5ress(re o each constit(ent.

Set No. 3

>"?A

7. A o(r c&inder 5etro& en'ine +or*in' on an air standard $tto cc&e has as+e5t

4o&(me o 2000 cm3 and the c&earance 4o&(me in each c&inder is ?0 cm3.%etermine

the cc&e eicienc. I the air at the )e'innin' o the com5ression stro*e isat "00

*5a and 300*, and the maxim(m cc&e tem5erat(re is "?D0 *, determinethe mean

eecti4e 5ress(re o the cc&e. >"?8. A R"2 4a5o(r com5ression reri'eration sstem is o5eratin' at acondenser 5res

s(re o "0 )ar and an e4a5orator 5ress(re o 2.2 )ar. Its reri'erationca5acit is

" tonnes. The 4a&(es o entha&5 at the in&et and o(t&et o thee4a5orator are

?D0 and 200 *;


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2 o 2


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Code No: 07A3EC08 Set No.





". 1a %ierentiate the cc&ic 5rocess and non cc&ic 5rocess.1nit I

1) A 4ac((m 'a('e connected to a tan* reads 30 =5a at a &ocation +here the)arometer reads 7DD mm #'. Ca&c(ate the a)so&(te 5ress(re in the tan*ass(min' densit o #' to )e "3,DJ0 *'?@"0

2. 1a %eri4e the ex5ression or sted &o+ ener' e(ation.1nit II

1) A )&o+er hand&es " *'?@"0

D. A 'as in a c&inder itted +ith a 5iston (nder'oes a cc&e com5osed o

three

5rocesses. -irst, the 'as ex5ands at constant 5ress(re +ith a heat addition o2.0 *; and a +or* o(t5(t o "2.0 *;. Then it is coo&ed at constant 4o&(me) a remo4a& o 8 *; o heat. -ina&&, an adia)atic 5rocess restores the 'asto its initia& state. %etermine

1a the +or* o the adia)atic 5rocess and

1) the stored ener' o the 'as at each o the other t+o states i its stored ener'in the initia& state is assi'ned the 4a&(e o Kero. >"?

?. The n(m)er o mo&es, the 5ress(res, and the tem5erat(res o 'ases a, ), and c are

'i4en as o&&o+sas m 1*' mo& 5 1*a t 10CN2 " 330 JDC$ 3 "0 "J0$2 2 ?80 28D

I the containers are connected, a&&o+in' the 'ases to mix ree&, ind

1a the 5ress(re and tem5erat(re o the res(&tin' mixt(re at e(i&i)ri(m, and


59/61

" o 2


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Code No: 07A3EC08 Set No.

1) the chan'e o entro5 o each constit(ent and that o the mixt(re.>"?

7. 1a hat is an air standard cc&e6 h are s(ch cc&es concei4ed6

1) -ind the air standard eiciencies or $tto cc&es +ith a com5ressionratio o ?

(sin' idea& 'ases ha4in' s5eciic heat ratios ".3D, ".3 and ".?2. hatare the

ad4anta'es and disad4anta'es o (sin' he&i(m as the +or*in' &(id6>?@"0

8.A oodreeKin' sstem re(ires 22 tonnes o reri'eration at ane4a5orator tem5erat(re o 30oC and a condenser tem5erat(re o 27oC. The reri'erant, R

"2, iss()coo&ed 3oC )eore enterin' the ex5ansion 4a&4e, and the 4a5o(r is

s(5erheatedoC )eore &ea4in' the e4a5orator. A sixc&inder sin'&eactin'

com5ressor +ithstro*e e(a& to )ore is to )e (sed, o5eratin' at "DD0 r5m. %etermine

1a the reri'eratin' eect

1) the reri'erant &o+ rate

1c the theoretica& 5iston dis5&acement 5er sec

1d the theoretica& 5o+er re(ired in *

1e the C$

1 the heat remo4ed in the condenser, and

1' the )ore and stro*e o the com5ressor. >"?


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104085614 JNTU Previous Paper Questions Thermodynamics