1 files changed, 47 insertions, 0 deletions
diff --git a/2870/CH17/EX17.5/Ex17_5.sce b/2870/CH17/EX17.5/Ex17_5.sce
new file mode 100755
index 000000000..a5b9c1738
--- /dev/null
+++ b/2870/CH17/EX17.5/Ex17_5.sce
@@ -0,0 +1,47 @@
+clc;clear;
+//Example 17.5
+
+//given data
+Vi=150;
+Ti=600+273;
+Pi=1;
+At=50/10000;//converted into m^2
+
+//from Table A-2a
+R=0.287;//in kJ/kg-K
+cp=1.005;//in kJ/kg-K
+k=1.4;
+
+//calculations
+Toi=Ti+Vi^2/(2*cp*1000);//factor of 1000 to convert kJ to J
+Poi=Pi*(Toi/Ti)^(k/(k-1));
+//flow is isentropic 
+//stagnation temp. and pressure values remain constant
+To=Toi;
+Po=Poi;
+//from Table 17–2
+//The critical-pressure ratio is 0.5283
+
+//Part a
+Pb=0.7;
+Pca=Pb/Po;
+// Pca > 0.5283
+//exit plane pressure is equal to the back pressure
+Pt=Pb;
+//from Table A–32
+Mat=0.778;
+//Tt/To = 0.892
+Tt=0.892*To;
+pt=Pt*1000/(R*Tt);//factor of 1000 to convert MPa to kPa
+Vt=Mat*sqrt(k*R*Tt*1000);//factor of 1000 to convert kJ to J
+ma=pt*At*Vt;
+disp(ma,'the mass flow rate through the nozzle when the back pressure is 0.7 MPa in kg/s');
+
+//Part b
+Pb=0.4;
+Pca=Pb/Po;
+// Pca < 0.5283
+//sonic conditions exists at the exit
+Ma=1;
+mb=At*(Po*1000)*(sqrt(k*1000/(R*To)))*(2/(k+1))^((k+1)/(2*(k-1)));//factor of 1000 to convert MPa to kPa and kJ to J
+disp(mb,'the mass flow rate through the nozzle when the back pressure is 0.4 MPa in kg/s');