// Theory and Problems of Thermodynamics // Chapter 4 // Energy Analysis of Process // Example 4 clear ;clc; //Given data m = 0.1 // mass wet steam in kg X1 = 0.8 // wet steam quality P1 = 0.3 // Pressure in MPa d = 0.8 // distance upto presence of latches in m A = 0.1 // Cross sectionla area of cylinder P1 = P1 * 1e3 // units conversion from MPa to kPa // at 0.3 MPa v_f = 0.001073 // Specific volume of vapor in m^3/kg v_g = 0.6058 // Specific volume of vapor in m^3/kg h_f = 516.47 // Specific enthalpy of vapor in kJ/kg h_fg = 2163.8 // Specific enthalpy of vapor in kJ/kg // Calculations v1 = X1*v_g + (1-X1)*v_f // Specific volume of vapor in m^3/kg V1 = v1* m // Initial Volume of steam in m^3 h1 = h_f + X1*h_fg // specific enthalpy at at 0.3MPa H1 = h1*m // Initial Enthalpy of steam in kJ // State of stem when piston touches the latches P2 = P1 // Pressure of steam when piston touches latch V2 = d*A // Volume of steam when piston touches latch v2 = V2/m // specific volume when piston touches latch W12 = P1*(V2 - V1) // Work done during constant pressure process // From superheated steam tables at P = 0.3 MPa and v3 = 0.8 m^3/kg T2 = 252.3 // Temperature in C h2 = 2972.28 // specific enthalpy obtained from interpolation H2 = h2*m // Enthalpy in kJ // Energy transfer during constant pressure process Q12 = H2 - H1 // Energy transferred in kJ // Constant Volume heating from P2 = 0.3 MPa to P3 = 0.5 MPa P3 = 0.5 // Final Pressure in MPa P3 = P3 * 1e3 // Units conversion from MPa to kPa v3 = v2 // From superheated steam tables at P = 0.3 MPa and v3 = 0.8 m^3/kg T3 = 595.6 // Temperature in C h3 = 3692.1 // specific enthalpy obtained from interpolation W23 = 0; Q23 = m*(h3-h2-v2*(P3-P2)) W = W12 + W23 Q = Q12 + Q23 // Output Results mprintf('Work done by the steam = %6.3f kJ',W) mprintf('\n Energy transferred = %6.2f kJ',Q) mprintf('\n Final Temperature of Steam = %6.1f `C',T3)