ISE,jan.2020 Problem 1: a)

Apply the Redlich-Kwong equation of state (Eq. 11.7 in Fundamentals of Engineering Thermodynamics) and specific heat capacities for ideal gases, cp_0 (T), from Table A21 to express the changes in specific internal energy, specific enthalpy and specific entropy from one state ( T , v ) to another, when both states are in gaseous phase. Hints: h=u+(pv); c_v=c_p - R; dx/(x-b)=ln(x-b)+C+; dx/(x*(x+b)) =1/b * ln(x/(x+b)) + C With the Redlich-Kwong equation, Eqs. 11.50-11.51 are easier to use than Eq.11.59-11.60. b) Determine the changes in specific internal energy, specific enthalpy and specific entropy for CO2 between T_1 =280K, v_1 =0,01m3/kg and T_2 =320K, v_2 =0,02m3/kg. At the specific volume of v0 = 10 m3 /kg , the pressure is so low that the gas can be assumed ideal. Hint: If you do the calculations here in a spreadsheet (or other code), you can replace the parameters (a, b) in the equation of state and repeat the calculations for another gas without any additional efforts. In this way, you can save much time later.