Q. What is 0th law and its signifcance? Q. Absolute Thermodynamic temperature scale? Q. Joule experiment? Q. What is 1st law o thermodynamics? Q. What is !nd law o thermodynamics? Q. "tate and #ro$e %arnots Theorum? Example 4.4. When a stationary mass of gas was compressed without friction at constant pressure its initial state of of 0.4 m3 and 0.105 MPa was found to change to nal state of 0.20 m3 and 0.105 MPa. here was a transfer of 42.5 !" of heat from the gas during the process process.. #ow much did the internal internal energy of the gas change $ %p144& pdf 'a(put)
Example 4.16. * 4.16. * +uid system undergoes a non,+ow non,+ow frictionless process process following the pressure,-olume relation relation as p & ' ( 1.5 where p is in /ar and is in m3. uring the process the -olume changes from 0.15 m3 to 0.05 m3 and the system re(ects 45 !" of heat. etermine )i* hange in internal energy )ii ii** hange in enthalpy enthalpy.. %P, % P,153& 153& 'a(put) Example 4.23. 0.2 m3 of air at 4 /ar and 130+ 130+ is contained in a system. * re-ersi/le adia/atic epansion ta!es place till the pressure falls to 1.02 /ar. he gas is then heated at constant pressure till enthalpy increases /y 2.5 !". alculate )i* he wor! done )ii ii** he inde of epansion& if the a/o-e processes are replaced /y a single re-ersi/le polytropic process gi-ing the same wor! wor! /etween the same initial initial and nal states. states. a!e c p
6 1 !", !",!g 7& c- 6 0.14 !", !",!g 7. %P, %P,158)& 158)& 'a(put
Example 4.27. * 4.27. * cylinder contains 0.45 m3 of a gas at 1 9 105 :,m2 and ;0<. he gas is compressed to a -olume of 0.13 m 3& the nal pressure /eing 5 9 105 :,m2. etermine )i* he mass of gas )ii ii** he -alue of inde =n> for compression )iii iii** he increase in internal energy of the gas )i- * he heat recei-ed or re(ected /y the gas during compression. a!e - & 1.4& ' 6 284.2 "?!g+ "?!g +. )#1/ 2a3put* Example 4.31. 0.1 m3 of an ideal gas at 300 7 and 1 /ar is compressed adia/atically to ;
/ar. @t is then cooled at constant -olume and further epanded isothermally so as to reach the condition from where it started. alculate )i* Pressure at the end of constant -olume cooling. )ii* hange in internal energy during constant -olume process. )iii* :et wor! done and heat transferred during the cycle. *ssume c p
6 14.3 !"?!g 7 and c - 6 10.2 !"?!g 7. %P,1A& 'a(put)
Example 4.32. 0.15 m3 of an ideal gas at a pressure of 15 /ar and 550 7 is epanded isothermally to 4 times the initial -olume. @t is then cooled to 280 7 at constant -olume and then compressed /ac! polytropically to its initial state. alculate the net wor! done and heat transferred during the cycle. %P,1A;& 'a(put) Example 4.33. * system consisting of 1 !g of an ideal gas at 5 /ar pressure and 0.02 m3 -olume eecutes a cyclic process comprising the following three distinct operations )i* 'e-ersi/le epansion to 0.0; m3 -olume& 1.5 /ar pressure& presuming pressure to /e a linear function of -olume ) p & a B / * )ii* 'e-ersi/le cooling at constant pressure and )iii* 'e-ersi/le hyper/olic compression according to law p 6 constant. his /rings the gas /ac! to initial conditions. )i* C!etch the cycle on p, diagram. )ii* alculate the wor! done in each process starting whether it is done on or /y the system and e-aluate the net cyclic wor! and heat transfer. %P,1A8& 'a(put) Example 4.37 @n an air compressor air +ows steadily at the rate of 0.5 !g?s through an air compressor. @t enters the compressor at A m,s with a pressure of 1 /ar and a specic -olume of 0.;5 m3,!g and lea-es at 5 m,s with a pressure of /ar and a specic -olume of 0.1A m3,!g. he internal energy of the air lea-ing is 80 !",!g greater than that of the air entering. ooling water in a (ac!et surrounding the cylinder a/sor/s heat from the air at the rate of A0 !",s. alculate )i* he power reDuired to dri-e the compressor )ii* he inlet and output pipe cross,sectional areas %P,180& 'a(put)
Example 4.41. he wor!ing +uid& in a steady +ow process +ows at a rate of 220 !g?min. he +uid re(ects 100 !",s passing through the system. he conditions of the +uid at inlet and outlet are gi-en as 1 6 320 m,s& p1 6 A.0 /ar& u1 6 2000 !",!g& - 1 6 0.3A m3,!g and 2 6 140 m?s& p2 6 1.2 /ar& u2 6 1400 !",!g& - 2 6 1.3 m3,!g. he suE 1 indicates the condition at inlet and 2 indicates at outlet of the system. )#145 2a3put* Example 4.43. 12 !g of air per minute is deli-ered /y a centrifugal air compressor. he inlet and outlet conditions of air are 1 6 12 m,s& p1 6 1 /ar& - 1 6 0.5 m3,!g and 2 6 80 m?s& p2 6 ; /ar& - 2 6 0.14 m3,!g. he increase in enthalpy of air passing through the compressor is 150 !"?!g and heat loss to the surroundings is 00 !",min. Find %i) Motor power reDuired to dri-e the compressor )ii* 'atio of inlet to outlet pipe diameter . *ssume that inlet and discharge lines are at the same le-el. %P,18A& 'a(put) Example 4.49. uring +ight& the air speed of a tur/o(et engine is 250 m,s. *m/ient air temperature is G 14+. Has temperature at outlet of noIIle is A10+. orresponding enthalpy -alues for air and gas are respecti-ely 250 and 800 !",!g. Fuel air ratio is 0.01;0. hemical energy of fuel is 45 M",!g. Jwing to incomplete com/ustion AK of chemical energy is not released in the reaction. #eat loss from the engine is 21 !",!g of air . alculate the -elocity of the ehaust (et . )#!0 2a3put*
