Question

s Q. Find the entropy and/or temperature of steam at the following states Region k/kg K) 5 MPa 1 MPa 18 MPa 400°C 40 kPa 40 kPa 120°C 50°C Quality, x-09, Mixed 71794 (<7.6700) Q. Determine the entropy change of water contained in a closed system as it changes phase rom saturated liquid to saturated vapor when the pressure is 0.1MPa and constant Why is the entropy change positive for this process? 2. Steam at 1 MPa, 6000C expands in a turbine to 001 Mpa. If the process is isentropic, ind the final temperature, final enthalpy of the steam, and the turbine work. 2 Aluminum at 100°C is placed in a large, insulated tank having 10 kg of water at a temperature of 30°C. If the mass of the aluminum is 05 kg, find the final equilibrium temperature of the aluminum and water, the entropy change of the aluminum and the water, and the total entropy change of the universe because of this process Before we rk the problem, what do you think the answers ought to be? Are entropy changes going negative? What about the entropy generated as the process takes place? to be positive or

Answer 1

(Si aj- P: 5 Mra ,Ts120°C Naher 's in Sub cooled reg ion From rabte of pxopeties of subcoeted water , enropy C) can be iven a S= 1,5234 kr/kg k region Thes Rrom superheaded steam table S- 7.18 122 KT/k<gk. in mixed region mixnaostecm wabel) 0253 C.0259 S 7.0046 kkg k CV at P 40 K, s S9 s mean waker is n mixed region

2. tabie 7-3588 - 302S 3 eqOA super h ecde steam i 2. Thu ' From Superheabed steon taole , S- 8-03094 KT/egk from above T-S dsagrarn , for isen tropic process (1-92) 2. 51< SS , mu it is in mixed Yegica Final Hee |T1. Tsar)。.cimn- temperature 45-307 °C hg: 2583, 886 /k4 kr/kg

Anl enthal py Chu) Torbine orkC can be Biven by W- 3698.555-254 33y 152 22 46 j/c9