clc // Example 1.5.py // Consider the air in the pressure vessel in Example 1.2. Let us now heat // the gas in the vessel. Enough heat is added to increase the temperature // to 600 K. Calculate the change in entropy of the air inside the vessel. // Variable declaration from example 1.2 V = 10 // volume of vessel (m^3) p = 20.0 // pressure (atm) T = 300.0 // initial temperature (K) T2 = 600.0 // final temperature (Kelvin) R = 287.0 // gas constant (J/Kg/K) gamma1 = 1.4 // ratio of specific heats for air // Calculations p2_by_p = T2/T // p2/p, at constant volume p/T = constant cv = R / (gamma1-1) // specific heat capacity at constant volume (J/Kg K) cp = cv + R // specific heat capacity at constant pressure (J/Kg K) p = p * 101000.0 // units conversion to N/m^2 rho = p/R/T // from ideal gas equation of state (Kg/m^3) m = V * rho // total mass = volume * density (Kg) // del_s = cp*log(T2/T) - R*log(p2_by_p) // change in entropy per unit mass (J/ Kg K) total_del_s = m*del_s // total change in entropy (J/K) // Result printf("\n Total change in entropy is %.3e J/K", total_del_s)