Chapter 6, Problem 6.68P

Air as ideal gas in the closed system, find the change of entropy from the initial to the final state, in Btu/lb oR ( degree R ). T1 = 360 oF (degree F), P1 = 14.7 psia T2 = 540 oF (degree F), P2 = 58.8 psia

ygotins lo 6.69) By injecting liquid water into superheated steam. the desuperheater shown in Fig. P6.69 has a saturated vapor stream at its exit. Steady-state operating data are provided in the accompanying table. Stray heat transfer and all kinetic neand potential energy effects are negligible. (a) Locate states to 1, 2, and 3 on a sketch of the T-s diagram. (b) Determine the rate of entropy production within the de-superheater, K.Modelthe in kW/K. ideal as State p(MPa) T°C) ) v × 10³(m³/kg) u(kJ/kg) h(kJ/kg) s(kJ/kg · K) 1 38 1.0065 X 10-3 166.5 168.3 0.5658 1B 0.1308 320 sat. vap. Y2807.9 3069.5 6.8452 3 1.5 1.159 2519.7 2693.6 7.2233 Desuperheater bol Liquid बेे कत 60°C. Det heet ni water 3. Saturated fos vapor P6.4recom O lo lguons 2 Superheated- vapor honor m2 = 0.03 kg/s motava bogisins odt 1ol,nW ni

A rigid tank containing air is subjected to a reversible process in which it is heated from its initial state at T, = 600 K and P, = 1.5 bar to a final state with P, = 4.325 bar. Assuming that air can be modelled as an ideal gas, determine the specific change in entropy As12, (kJ/kg-K). Your Answer: