Question

Chapter 07-31E revised (9th ed.) Given: Two Ibm of saturated water mixture at 300 psia fill a weighted piston-cylinder whose initial volume is 2.5 ft. The water is then heat at constant pressure until the temperature reaches 500°F. HO 300 psia 2 lbm 2.5 ft Find: (a) Draw the process on a P-v diagram (b) Total amount of work done (c) Entropy change for the system Solution:

Answer 1

solution :- - mass of saturated water mixture, m=2 lbm Initial state 0: Pressure, Pi= 300 psia &i= 2.5 ft² Volume, i specific volume, viz V. V = 1.25 ft3/L6m final state ②: Temperature, Tz = 500°F PROCESS - is an constant process. Pressure Heat addition negligible. Assumptions : changes in kinetic and Potential energies are Cre; AK6 = 0 and SPE=0) . Properties remains constant. Cie; Quasi-static process) ANALYES! @ ANALYSIS P P = P2 = 3oopsiat - - - T2 = 500 °F - TI = Tsat @p z 417.350F - - - + Vy NOTE: since since, I s T Tz > Tsat @ 300 psia : Water is in superheated Megion at state ©.

Quality at state 0 x = o. do7 ~ 0.dl Siz & +21 (Sgi - Sf) z 058418 +0.81 (1511) - 0.58818) 2 1.3357 Bru/lom "R Entropy change for the system as = (S2-31) > mC82-41) 22 ( 125706 - 1,3357) AS = 0.469d Btu/or huyo