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UNIVERSITY QP / QB

QUESTION BANK

Third Semester Mechanical Engineering

1. ENGINEERING THERMO DYNAMICS (ME 2202)

1. What do you understand by pure substance

! pure substance "s de#ned as one that "s ho$o%eneous and "n&ar"ab'e

"n

che$"ca' co$pos"t"on throu%hout "ts $ass.

(. )e#ne ther$odyna$"c syste$.

! ther$odyna$"c syste$ "s de#ned as a *uant"ty o+ $atter or a re%"on

"n space,on -h"ch the ana'ys"s o+ the prob'e$ "s concentrated.

. Na$e the d"erent types o+ syste$.

0'osed syste$ on'y ener%y trans+er and no $ass trans+er2

3pen syste$ Both ener%y and $ass trans+er2

Iso'ated syste$ No $ass and ener%y trans+er2

4. )e#ne ther$odyna$"c e*u"'"br"u$.

I+ a syste$ "s "n 5echan"ca', Ther$a' and 0he$"ca' E*u"'"br"u$ then

the syste$

"s "n ther$odyna$"ca''y e*u"'"br"u$. or2

I+ the syste$ "s "so'ated +ro$ "ts surround"n% there -"'' be no chan%e "n

the

$acroscop"c property, then the syste$ "s sa"d to e6"st "n a state o+

ther$odyna$"c e*u"'"br"u$.

7. What do you $ean by *uas"8stat"c process

E*u"'"br"u$ state

Quas"8stat"c process

In#n"te s'o-ness "s the character"st"c +eature o+ a *uas"8stat"c process.

! *uas"stat"c process "s that a success"on o+ e*u"'"br"u$ states. !

*uas"8stat"c process "s a'so ca''ed as re&ers"b'e process.

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9. )e#ne Path +unct"on.

The -or: done by a process does not depend upon the end o+ the

process. It

depends on the path o+ the syste$ +o''o-s +ro$ state 1 to state (.

;ence -or: "s

ca''ed a path +unct"on.

. E6p'a"n ho$o%eneous and hetero%eneous syste$.

The syste$ cons"st o+ s"n%'e phase "s ca''ed ho$o%eneous syste$ and

the syste$ cons"st o+ $ore than one phase "s ca''ed hetero%eneous

syste$.

1?. What "s a steady @o- process

Steady @o- $eans that the rates o+ @o- o+ $ass and ener%y across

the contro'

sur+ace are constant.

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11. Pro&e that +or an "so'ated syste$, there "s no chan%e "n "nterna'

ener%y.

In "so'ated syste$ there "s no "nteract"on bet-een the syste$ and the

surround"n%s. There "s no $ass trans+er and ener%y trans+er. !ccord"n%

to #rst

'a- o+ ther$odyna$"cs as dQ A dU dWC dU A dQ D dWC dQ A ?, dW

A ?,

There +ore dU A ? by "nte%rat"n% the abo&e e*uat"on U A constant,

there+ore the

"nterna' ener%y "s constant +or "so'ated syste$.

1(. Ind"cate the pract"ca' app'"cat"on o+ steady @o- ener%y e*uat"on.

1. Turb"ne, (. No'e, . 0ondenser, 4. 0o$pressor.

1. )e#ne syste$.

It "s de#ned as the *uant"ty o+ the $atter or a re%"on "n space upon

-h"ch -e

+ocus attent"on to study "ts property.

14. )e#ne cyc'e.

It "s de#ned as a ser"es o+ state chan%es such that the #na' state "s

"dent"ca' -"ththe "n"t"a' state.

17. Sho- that -or: "s a path +unct"on and not a property.

19. E6p'a"n 5echan"ca' e*u"'"br"u$.

I+ the +orces are ba'anced bet-een the syste$ and surround"n%s are

ca''ed

5echan"ca' e*u"'"br"u$

1

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"s "n Ther$a' e*u"'"br"u$.

1>. )e#ne Feroth 'a- o+ Ther$odyna$"cs.

When t-o syste$s are separate'y "n ther$a' e*u"'"br"u$ -"th a th"rd

syste$ then

they the$se'&es are "n ther$a' e*u"'"br"u$ -"th each other.

(?. What are the '"$"tat"ons o+ #rst 'a- o+ ther$odyna$"cs

a. !ccord"n% to #rst 'a- o+ ther$odyna$"cs heat and -or: are

$utua''y con&ert"b'e dur"n% any cyc'e o+ a c'osed syste$.

b. But th"s 'a- does notspec"+y the poss"b'e cond"t"ons under -h"ch

the heat "s con&erted "nto-or:.

c. !ccord"n% to the #rst 'a- o+ ther$odyna$"cs -e canGt pro&e that

"t "s "$poss"b'e to trans+er heat +ro$ 'o-er te$perature to h"%her

te$perature.

d. It does not %"&e any "n+or$at"on re%ard"n% chan%e o+ state or

-hether theprocess "s poss"b'e or not.

e. The I 'a- does not spec"+y the d"rect"on o+ heat and -or:.

(1. What "s perpetua' $ot"on $ach"ne o+ #rst :"nd

It "s de#ned as a $ach"ne, -h"ch produces -or: ener%y -"thout

consu$"n% ane*u"&a'ent o+ ener%y +ro$ other source. It "s "$poss"b'e to obta"n "n

actua'

pract"ce, because no $ach"ne can produce ener%y o+ "ts o-n -"thout

consu$"n%

any other +or$ o+ ener%y.

((. )e#ne 0'aus"us state$ent.

It "s "$poss"b'e +or a se'+8act"n% $ach"ne -or:"n% "n a cyc'"c process, to

trans+er

heat +ro$ a body at 'o-er te$perature to a body at a h"%her

te$perature -"thout

the a"d o+ an e6terna' a%ency.

(. What "s Perpetua' $ot"on $ach"ne o+ the second :"nd

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! heat en%"ne, -h"ch con&erts -ho'e o+ the heat ener%y "nto

$echan"ca' -or: "s

:no-n as Perpetua' $ot"on $ach"ne o+ the second :"nd.

(4. )e#ne He'&"n P'anc: State$ent.

It "s "$poss"b'e to construct a heat en%"ne to produce net-or: "n a

co$p'ete cyc'e

"+ "t e6chan%es heat +ro$ a s"n%'e reser&o"r at s"n%'e #6ed te$perature.

(7. )e#ne ;eat pu$p.

! heat pu$p "s a de&"ce, -h"ch "s -or:"n% "n a cyc'e and trans+ers heat

+ro$

'o-er te$perature to h"%her te$perature.

(9. )e#ne ;eat en%"ne.

;eat en%"ne "s a $ach"ne, -h"ch "s used to con&ert the heat ener%y

"nto $echan"ca' -or: "n a cyc'"c process.

(

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1. E6p'a"n entropy

It "s an "$portant ther$odyna$"c property o+ the substance. It "s the

$easure o+

$o'ecu'ar d"sorder. It "s denoted by S. The $easure$ent o+ chan%e "n

entropy

+or re&ers"b'e process "s obta"ned by the *uant"ty o+ heat rece"&ed or

reJected to

abso'ute te$perature.

(. What "s abso'ute entropy

The entropy $easured +or a'' per+ect crysta''"ne so'"ds at abso'ute ero

te$perature "s :no-n as abso'ute entropy.

. )e#ne a&a"'ab"'"ty.

The $a6"$u$ use+u' -or: obta"ned dur"n% a process "n -h"ch the #na'

cond"t"on

o+ the syste$ "s the sa$e as that o+ the surround"n% "s ca''ed

a&a"'ab"'"ty o+ the

syste$.

4. )e#ne a&a"'ab'e ener%y and una&a"'ab'e ener%y.

!&a"'ab'e ener%y "s the $a6"$u$ ther$a' use+u' -or: under "dea'cond"t"on. The

re$a"n"n% part, -h"ch cannot be con&erted "nto -or:, "s :no-n as

una&a"'ab'e

ener%y.

7. E6p'a"n the ter$ source and s"n:.

Source "s a ther$a' reser&o"r, -h"ch supp'"es heat to the syste$ and

s"n: "s a

ther$a' reser&o"r, -h"ch ta:es the heat +ro$ the syste$.

9. What do you understand by the entropy pr"nc"p'e

The entropy o+ an "so'ated syste$ can ne&er decrease. It a'-ays

"ncreases and

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re$a"ns constant on'y -hen the process "s re&ers"b'e. Th"s "s :no-n as

pr"nc"p'e

o+ "ncrease "n entropy or entropy pr"nc"p'e.

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The rat"o o+ actua' cyc'e ec"ency to that o+ the "dea' cyc'e ec"ency "s

ter$ed as ec"ency rat"o.

4(. )e#ne o&era'' ec"ency.

It "s the rat"o o+ the $echan"ca' -or: to the ener%y supp'"ed "n the +ue'.

It "s a'so

de#ned as the product o+ co$bust"on ec"ency and the cyc'e

ec"ency.

4. )e#ne spec"#c stea$ consu$pt"on o+ an "dea' Ran:"ne cyc'e.

It "s de#ned as the $ass @o- o+ stea$ re*u"red per un"t po-er output.

44. Na$e the d"erent co$ponents "n stea$ po-er p'ant -or:"n% on

Ran:"ne cyc'e. Bo"'er, Turb"ne, 0oo'"n% To-er or 0ondenser and Pu$p.

47. What are the eects o+ condenser pressure on the Ran:"ne

0yc'e

By 'o-er"n% the condenser pressure, -e can "ncrease the cyc'e

ec"ency. The $a"n d"sad&anta%e "s 'o-er"n% the bac: pressure "n

rease the -etness o+ stea$. Isentrop"c co$press"on o+ a &ery -et

&apour "s &ery d"cu't.

49. 5ent"on the "$pro&e$ents $ade to "ncrease the "dea' ec"ency

o+ Ran:"ne cyc'e.1. Ko-er"n% the condenser pressure.

(. Superheated stea$ "s supp'"ed to the turb"ne.

. Increas"n% the bo"'er pressure to certa"n '"$"t.

4. I$p'e$ent"n% reheat and re%enerat"on "n the cyc'e.

4

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"ncreases the cost o+ the p'ant due to the reheats and "ts &ery 'on%

connect"ons.

4>. What are the ad&anta%es o+ reheat cyc'e

1. It "ncreases the turb"ne -or:.

(. It "ncreases the heat supp'y.

. It "ncreases the ec"ency o+ the p'ant.

4. It reduces the -ear on the b'ade because o+ 'o- $o"sture content "n

KP state o+ the turb"ne.

7?. )e#ne 'atent heat o+ e&aporat"on or Entha'py o+ e&aporat"on.

The a$ount o+ heat added dur"n% heat"n% o+ -ater up to dry stea$

+ro$ bo"'"n% po"nt "s :no-n as Katent heat o+ e&aporat"on or entha'py

o+ e&aporat"on.

71. E6p'a"n the ter$ super heated stea$ and super heat"n%.

The dry stea$ "s +urther heated "ts te$perature ra"ses, th"s process "s

ca''ed as superheat"n% and the stea$ obta"ned "s :no-n as

superheated stea$.

7(. E6p'a"n heat o+ super heat or super heat entha'py.

The heat added to dry stea$ at 1??o0 to con&ert "t "nto super heated

stea$ at the te$perature Tsup "s ca''ed as heat o+ superheat or superheat entha'py.

7. E6p'a"n the ter$ cr"t"ca' po"nt, cr"t"ca' te$perature and cr"t"ca'

pressure.

In the T8S d"a%ra$ the re%"on 'e+t o+ the -ater'"ne, the -ater e6"sts as

'"*u"d. In

r"%ht o+ the dry stea$ '"ne, the -ater e6"sts as a super heated stea$.

In bet-een

-ater and dry stea$ '"ne the -ater e6"sts as a -et stea$. !t a

part"cu'ar po"nt, the -ater "s d"rect'y con&erted "nto dry stea$ -"thout

+or$at"on o+ -et stea$. The po"nt "s ca''ed cr"t"ca' po"nt. The cr"t"ca'

te$perature "s the te$perature abo&e -h"ch a substance cannot e6"st

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as a '"*u"d, the cr"t"ca' te$perature o+ -ater "s

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It "s de#ned as a %as ha&"n% no +orces o+ "nter$o'ecu'ar attract"on.

These %ases

-"'' +o''o- the %as 'a-s at a'' ran%es o+ pressures and te$peratures.

9(. )e#ne Rea' %as.

It "s de#ned, as a %as ha&"n% the +orces o+ attract"on bet-een

$o'ecu'es tends to

be &ery s$a'' at reduced pressures and e'e&ated te$peratures.

9. What "s e*uat"on o+ state

The re'at"on bet-een the "ndependent propert"es such as pressure,

spec"#c &o'u$e and te$perature +or a pure substance "s :no-n as the

e*uat"on o+ state.

94. State Boy'eGs 'a-.

It states that &o'u$e o+ a %"&en $ass o+ a per+ect %as &ar"es "n&erse'y

as the

abso'ute pressure -hen te$perature "s constant.

97. State 0har'eGs 'a-.

It states that "+ any %as "s heated at constant pressure, "ts &o'u$e

chan%es d"rect'y as "ts abso'ute te$perature.

99. E6p'a"n the construct"on and %"&e the use o+ %enera'"edco$press"b"'"ty chart.

The %enera' co$press"b"'"ty chart "s p'otted -"th F &ersus Pr +or &ar"ous

&a'ues o+

Tr. Th"s "s constructed by p'ott"n% the :no-n data o+ one o+ $o'e %ases

and can

be used +or any %as. Th"s chart %"&es best resu'ts +or the re%"ons -e''

re$o&ed

+ro$ the cr"t"ca' state +or a'' %ases.

9

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9=. E6p'a"n 'a- o+ correspond"n% states.

I+ any t-o %ases ha&e e*ua' &a'ues o+ reduced pressure and reduced

te$perature, then they ha&e sa$e &a'ues o+ reduced &o'u$e.

9>. E6p'a"n )a'tonGs 'a- o+ part"a' pressure.

The pressure o+ a $"6ture o+ %ases "s e*ua' to the su$ o+ the part"a'

pressures o+

the const"tuents. The part"a' pressure o+ each const"tuent "s that

pressure -h"ch

the %as -ou'd e6pect "+ "t occup"ed a'one that &o'u$e occup"ed by the

$"6tures at

the sa$e te$peratures. $ A $!$B$0. A O$"

$" A $ass o+ the const"tuent.

PAP!PBP0. A OP", P" D the part"a' pressure o+ a const"tuent.

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The tota' pressure e6erted "n a c'osed &esse' conta"n"n% a nu$ber o+

%ases "s e*u' to the su$ o+ the pressures o+ each %as and the &o'u$e

o+ each %as e*ua' to the &o'u$e o+ the &esse'.

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The eect"&e te$perature "s a $easure o+ +ee'"n% -ar$th or co'd to

the hu$an

body "n response to the a"r te$perature, $o"sture content and a"r

$ot"on. I+ the

a"r at d"erent )BT and R; cond"t"on carr"es the sa$e a$ount o+ heat

as the heat carr"ed by the a"r at te$perature T and 1?? R;, then the

te$perature T "s

:no-n as eect"&e te$perature.

. Represent the +o''o-"n% psychro$etr"c process us"n% s:e'eton

psychro$etr"c

chart a2 0oo'"n% and dehu$"d"#cat"on, b2 E&aporat"&e coo'"n%.

=?. )e#ne Re'at"&e hu$"d"ty.

It "s de#ned as the rat"o o+ part"a' pressure o+ -ater &apour p-2 "n a

$"6ture to the

saturat"on pressure ps2 o+ pure -ater at the sa$e te$perature o+

$"6ture.

=1. )e#ne spec"#c hu$"d"ty.

It "s de#ned as the rat"o o+ the $ass o+ -ater &apour $ s2 "n a %"&en

&o'u$e to the$ass o+ dry a"r "n a %"&en &o'u$e $a2.

=(. )e#ne de%ree o+ saturat"on.

It "s the rat"o o+ the actua' spec"#c hu$"d"ty and the saturated spec"#c

hu$"d"ty at

the sa$e te$perature o+ the $"6ture.

=. What "s de- po"nt te$perature

The te$perature at -h"ch the &apour starts condens"n% "s ca''ed de-

po"nt

te$perature. It "s a'so e*ua' to the saturat"on te$perature at the

part"a' pressure o+ -ater &apour "n the $"6ture. The de- po"nt

te$perature "s an "nd"cat"on o+

spec"#c hu$"d"ty.

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=4. What "s $eant by dry bu'b te$perature )BT2

The te$perature recorded by the ther$o$eter -"th a dry bu'b. The dry

bu'b

ther$o$eter cannot aected by the $o"sture present "n the a"r. It "s

the $easure

o+ sens"b'e heat o+ the a"r.

=7. What "s $eant by -et bu'b te$perature WBT2

It "s the te$perature recorded by a ther$o$eter -hose bu'b "s

co&ered -"th

cotton -"c: -et2 saturated -"th -ater. The -et bu'b te$perature $ay

be the

$easure o+ entha'py o+ a"r. WBT "s the 'o-est te$perature recorded by

$o"stened bu'b.

=9. )e#ne de- po"nt depress"on.

It "s the d"erence bet-een dry bu'b te$perature and de- po"nt

te$perature o+ a"r &apour $"6ture.

=

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-et bu'b te$perature, re'at"&e hu$"d"ty and entha'py are the

propert"es appeared

"n the psychro$etr"c chart.

>?. )e#ne sens"b'e heat and 'atent heat.

Sens"b'e heat "s the heat that chan%es the te$perature o+ the

substance -hen

added to "t or -hen abstracted +ro$ "t. Katent heat "s the heat that

does not aect

the te$perature but chan%e o+ state occurred by add"n% the heat or by

abstract"n% the heat.

>1. What are the "$portant psychro$etr"c process

1.Sens"b'e heat"n% and sens"b'e coo'"n%, (. 0oo'"n% and

dehu$"d"#cat"on, .;eat"n% and hu$"d"#cat"on, 4. 5"6"n% o+

a"r strea$s, 7. 0he$"ca'

dehu$"d"#cat"on, 9. !d"abat"c e&aporat"&e coo'"n%.

>(. What "s $eant by ad"abat"c $"6"n%

The process o+ $"6"n% t-o or $ore strea$ o+ a"r -"thout any heat

trans+er to the surround"n% "s :no-n as ad"abat"c $"6"n%. It "s

happened "n a"r cond"t"on"n% syste$.>. What are the assu$pt"ons $ade "n Van )er -aa'Gs e*uat"on o+

state

There "s no "nter $o'ecu'ar +orces bet-een part"c'es. The &o'u$e o+

$o'ecu'es "s ne%'"%"b'e "n co$par"son -"th the %as.

>4. )e#ne coec"ent o+ &o'u$e e6pans"on.

The coec"ent o+ &o'u$e e6pans"on "s de#ned as the chan%e "n

&o'u$e -"th the chan%e "n te$perature per un"t &o'u$e :eep"n% the

pressure constant. It "s denoted by .

>7. State ;e'$ho't +unct"on.

;e'$ho't +unct"on "s the property o+ a syste$ and "s %"&en by

subtract"n% the product o+ abso'ute te$perature T2 and entropy S2

+ro$ the "nterna' ener%y U2.

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;e'$ho't +unct"on A U D TS

>9. What are ther$odyna$"c propert"es

Ther$odyna$"c propert"es are pressure p2, te$perature T2, &o'u$e V2,

"nterna' ener%y U2, entha'py;2, entropy S2, ;e'$ho't +unct"on 2 and

"bbs +unct"on

>

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1. A system receives 42 kJ of heat while expanding with volume change of 0.123 m 3against anatmosphere of

12 !cm2. A mass of "0 kg in the surroundings is also lifted through a distance of # metres.

(i) $ind the change in energy of the system.

(ii) %he system is returned to its initial volume &y an adia&atic process which re'uires

100 kJ of work. $ind the change in energy of system.(iii) (etermine the total change in energy of the system.

)Ans. *i+ 22.,4 kJ- *ii+ 100 kJ- *iii+ 122.,4 kJ

(. A tank contains 2.2# m3of air at a pressure of 24.12 &ar. /f air is cooled until its pressure andtemperature &ecomes 13." &ar and 21.1 respectively. (etermine the decrease of internal

energy.

) ,",.3# kJ

. (etermine work done &y fluid in the thermodynamic cycle comprising of following processes *a+ 5nit mass of fluid at 20 atm and 0.04 m3 is expanded &y the law PV1., 6 constant- till volume

gets dou&led.

*b+ $luid is cooled iso&arically to its original volume.

*c+ 7eat is added to fluid till its pressure reaches to its original pressure- isochorically.)1"." kJ

4. Air at " &ar- 100 flows in a duct of 1, cm diameter at rate of 1,0 kg!min. /t is then throttled &ya valve upto 4 &ar pressure. (etermine the velocity of air after throttling and also show that

enthalpy remains constant &efore and after throttling.

)3." m!s

7. (etermine the power re'uired &y a compressor designed to compress atmospheric air *at 1 &ar-20+

to 10 &ar pressure. Air enters compressor through inlet area of 80cm2 with velocity of ,0 m!s and

leaves with velocity of 120 m!s from exit area of , cm2. onsider heat losses to environment to

&e 109 of power input to compressor.

),0.4

k:9. A frictionless piston is free to move in a closed cylinder. /nitially there is 0.03, m3 of oxygen at

4., &ar- #0 on one side of the piston and 0.0 m3of methane at 4., &ar and 12 on the other

side. %he cylinder walls and piston may &e regarded as perfect thermal insulators &ut the oxygen

may &e heated electrically. 7eating takes place so that the volume of oxygen dou&les. $ind

(i) $inal state condition ; *ii+ :ork done &y the piston ;

(ii) 7eat transferred to oxygen.

%reat &oth gases as perfect and take

$or oxygen cp6 0."" kJ!kg

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-here T "s "n 0. The pressure dur"n% the process "s $a"nta"ned at ( bar and &o'u$e chan%es+ro$ 1 $to 1.= $

and te$perature chan%es +ro$ 7?0 to 47?0.)eter$"ne i2 ;eat added ii2 Wor: done

iii2 0han%e "n "nterna' ener%y iv2 0han%e "n entha'py.=. %he resistance of the winding in a certain motor is found to &e , ohms at room *2, o+. :hen

operating at full load under steady state conditions- the motor is switched off and the resistance of

the winding s is immediately measured again- and found to &e 80 ohms. %he windings are made

of copper whose resistance at temperature t o id given &y =t6 =o)1>0.00383t where =0is the

resistance at 00. $ind the temperature of the coil during full load

>. ! certa"n -or:"n% @u"d under%oes a process "n such a -ay that pressure and

&o'u$e are re'ated as 0.2,+=

Vp , Where p "s "n :Pa and V "s "n $. )ur"n%

the process the &o'u$e chan%es +ro$ ?.17 $to ?.1 $. )eter$"ne the -or:done "n the process.

1?.A gas occupies 0.3m3at 2 &ar. /t undergoes a cycle consisting of the following processes a+1?2constant pressure process with work interaction of 1,kJ &+2?3 constant temperature process and

@36@2 c+ 3?1 constant volume and change in internal energy @1?@3 is?40kJ. (etermine network

and net heat transfer for the cycle.

11.! p"ston8cy'"nder asse$b'y conta"ns 1:% or n"tro%en at 1?? :Pa. The "n"t"a'

&o'u$e "s ?.7 $

. ;eat "s trans+erred to the substance "n an a$ountnecessary to cause a s'o- e6pans"on at constant te$perature. Th"s process"s ter$"nated -hen the #na' &o'u$e "s t-"ce the "n"t"a' &o'u$e. Est"$ate the

a$ount o+ heat trans+erred.5o'ecu'ar -t. (= 0&A?.

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17.! p"ston8cy'"nder asse$b'y conta"ns 1:% or n"tro%en at 1?? :Pa. The "n"t"a'

&o'u$e "s ?.7 $

. ;eat "s trans+erred to the substance "n an a$ountnecessary to cause a s'o- e6pans"on at constant te$perature. Th"s process"s ter$"nated -hen the #na' &o'u$e "s t-"ce the "n"t"a' &o'u$e. Est"$ate thea$ount o+ heat trans+erred.5o'ecu'ar -t. (= 0&A?.

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(4.%hree reversi&le engines of arnot type are operating in series &etween the limiting

temperatures of 1100 < and 300

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&. /f the inlet area is 800 cm2 and the specific volume at inlet is 0.1" m3!kg- find

the mass flow rate.

c. /f the specific volume at the noCCle exit is 0.48" m3!kg- find the exit area ofnoCCle. )"

?.A fluid system- contained in a piston and cylinder machine- passes through a completecycle of four processes. %he sum of all heat transferred during a cycle is 340 kJ. %he

system completes 200 cycles per min. omplete the following ta&le showing the method

for each item- and compute the net rate of work output in k:. )"

Process Q (kJ/min) W (kJ/min) E (kJ/min)

1H2 0 4340 H2H3 42000 0 H

3H4 4200 H 3200

4H1 H H III

1.(uring flight- the air speed of a tur&oDet engine is 2,0 m!s. Am&ient air temperature is 14. as temperature at outlet of noCCle is #10. orresponding enthalpy values for air

and gas are respectively 2,0 and 800 kJ!kg. $uel air ratio is 0.01"0. hemical energy of

fuel is 4, J!kg. Fwing to incomplete com&ustion #9 of chemical energy is not releasedin the reaction. 7eat loss from the engine is 21 kJ!kg of air. alculate the velocity of the

exhaust Det. )"

(.%he connections of a reversi&le engine to three sources at ,00

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.3 kg of water at "0 is mixed with 4 kg of water at 1, in an isolated system.

alculate the change of entropy due to mixing process.

4.%wo tanks A and E contain 1 kg of air at 1 &ar- ,0G and 3 &ar- ,0G when atmosphere is

at 1 &ar-1,G. /dentify the tank in which stored energy is more. Also find the availa&ility

of air in each tank.

7.A cold storage plant of 40 tonnes of refrigeration capacity runs with its performance Dust 1!4 th of itsarnot FB. /nside temperature is 1,G and atmospheric temperature is

3,G. (etermine the powerre'uired to run the plant. )%ake Fne ton of refrigeration as

3.,2 k:

9.A vessel of volume 0.2 m3 has 2 kg of water at 200 o find p- h and x

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&efore mixing with the feed water heater. Kteam for the open feed water heater is &led

from L.B. tur&ine at , &ar. (etermine

*i+ $raction of steam extracted from the tur&ines at each &led heater- and *ii+ %hermal efficiency of the system.

(raw the line diagram of the components and represent the cycle on %?s diagram.

4.%he atmospheric conditions are 30G and specific humidity of 0.021, kg!kg of air.(etermine

(i) Bartial pressure of air

(ii) =elative humidity

*iii+ (ew point temperature. Atmospheric pressure 6 ,# mm 7g.

44.1 kg of air at 24G and a relative humidity of 09 is to &e mixed adia&atically in a steady

state- steady flow device with 1 kg of air at 1#G and a relative humidity of 109.Assuming that the mixing is to &e carried out at a constant pressure of 1.0 atm- determine

the temperature and relative humidity of the stream leaving the device.

47./n a la&oratory test- a psychrometer recorded 3#G (E% and 30G :E%. alculate

(i) Mapour pressure(ii) =elative humidity

(iii) Kpecific humidity

(iv) (egree of saturation(v) (ew point temperature(vi) @nthalpy of the mixture.

49.An air?water vapour mixture enters an adia&atic saturator at 30G and leaves at 20G-which is the adia&atic saturation temperature. %he pressure remains constant at 1 &ar.

(etermine the relative humidity and the humidity ratio of the inlet mixture.

4

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&ul& temperature 2,o. %he fresh air is drawn at the rate of 100m3!min. %he returned air

from conditioned space has the drug &ul& temperature 23o and relative humidity ,09.

%he volume flow rate of it ,40 m3!min. (etermine the *i+ dry &ul& and we& &ul&temperature *ii+ specific humidity of mixture

,0 $ind the value of co?efficient of volume expansion N and isothermal compressi&ility < for aMan der :aalsO gas o&eying