Question

QUESTION 2 A piston-cylinder device contains 5 kg of saturated water liquid at 0.3 MPa. Heat is transferred at constant pressure until the temperature reaches 500 °C. (84 marks) a) What is the initial temperature of the system? b) What is the initial quality x? c) What is the initial specific enthalpy of the system? d) What is the final state? e) Show the process on a P-v diagram with respect to the saturation line. f) What is the final specific enthalpy? g) Calculate the change in total volume during the process h) Calculate the total enthalpy increase during the process. Formulae m Х v=v, + x(v, - v,) In mixture region, u=u, + xur h ah, + xh m AH=m(hz-h:) AV=m(vz-V.)

Answer 1

Given m=5K9 P = P = 0.3mpa, 5=500°c, Istial state in Saturated liquid State Intial temperatur As the water is of Saturated liquid state intrety T = Tot 183.52 6 quality Intially water is of Saturated liquid store XO From stean stable) We are of obtaining volces below © Intial specific enthalpy From steam table at P = 0.3mpa, s=0 h, - 561.4313 kg a final state Super i Saturated As P = 0.3mpor, T2 = 500c, final state is a 3) State.

P- v diagram P P = Pirosupy Find Specofic entlapy We have From steam table at p = 0.3mpo, Ta=500c h2 = 34866 I/19, Change in total volume Froon steam table We hatte at P,=0.3MPa, x=0 - V= 0.001073 poleg And at P2=0-3mpo, To=5000 we have 1-18692 08/19

2. Change total volume V-m (UV V-5 (1-18672 – 0-001073) V= 5.928 m Change in total entalpy TH=m (ha-hi) H=5.(3486-6- 560.43) H= 14625-85 k3,