From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 572/CH9/EX9.3/c9_3.sce | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100755 572/CH9/EX9.3/c9_3.sce (limited to '572/CH9/EX9.3') diff --git a/572/CH9/EX9.3/c9_3.sce b/572/CH9/EX9.3/c9_3.sce new file mode 100755 index 000000000..3046be53b --- /dev/null +++ b/572/CH9/EX9.3/c9_3.sce @@ -0,0 +1,52 @@ +//(9.3) At the beginning of the compression process of an air-standard dual cycle with a compression ratio of 18, the temperature is 300 K and the pressure is 0.1 MPa. The pressure ratio for the constant volume part of the heating process is 1.5:1. The volume ratio for the constant pressure part of the heating process is 1.2:1. Determine (a) the thermal efficiency and (b) the mean effective pressure, in MPa. + + +//solution + +//variable initialization +T1 = 300 //beginning temperature in kelvin +p1 = .1 //beginning pressure in MPa +r = 18 //compression ratio +pr = 1.5 //The pressure ratio for the constant volume part of the heating process +vr = 1.2 // The volume ratio for the constant pressure part of the heating process + +//analysis +//States 1 and 2 are the same as in Example 9.2, so +u1 = 214.07 //in kj/kg +T2 = 898.3 //in kelvin +u2 = 673.2 //in kj/kg +//Since Process 2–3 occurs at constant volume, the ideal gas equation of state reduces to give +T3 = pr*T2 //in kelvin +//Interpolating in Table A-22, we get +h3 = 1452.6 //in kj/kg +u3 = 1065.8 //in kj/kg +//Since Process 3–4 occurs at constant pressure, the ideal gas equation of state reduces to give +T4 = vr*T3 //in kelvin +//From Table A-22, +h4 = 1778.3 //in kj/kg +vr4 = 5.609 +//Process 4–5 is an isentropic expansion, so +vr5 = vr4*r/vr +//Interpolating in Table A-22, we get +u5 = 475.96 //in kj/kg + +//part(a) +eta = 1-(u5-u1)/((u3-u2)+(h4-h3)) +printf('the thermal efficiency is: %f',eta) + +//part(b) +//The specific volume at state 1 is evaluated in Example 9.2 as +v1 = .861 //in m^3/kg +mep = (((u3-u2)+(h4-h3)-(u5-u1))/(v1*(1-1/r)))*10^3*10^-6 //in MPa +printf('\nthe mean effective pressure, in MPa is: %f',mep) + + + + + + + + + + + -- cgit